Derek F. Amanatullah, MD, PhD

All Publications

• Surgery Before Subspecialty Referral for Periprosthetic Knee Infection Reduces the Likelihood of Infection Control. Clinical orthopaedics and related research Song, S. Y., Goodman, S. B., Suh, G., Finlay, A. K., Huddleston, J. I., Maloney, W. J., Amanatullah, D. F. 2018

  Abstract

  BACKGROUND: Failure to control a periprosthetic joint infection (PJI) often leads to referral of the patient to a tertiary care institution. However, there are no data regarding the effect of prior surgical intervention for PJI on subsequent infection control.QUESTIONS/PURPOSES: (1) Is the likelihood of 2-year infection-free survival worse if an initial surgery for PJI was performed before referral to a tertiary care center when compared with after referral for definitive treatment? (2) Is the likelihood of identifying a causal organism during PJI worse if the initial surgery for PJI was performed before referral to a tertiary care center when compared with after referral for definitive treatment? (3) We calculated how many patients are harmed by the practice of surgically attempting to treat PJI before referral to a tertiary care center when compared with treatment after referral to a tertiary care center for definitive treatment.METHODS: Among 179 patients (182 TKAs) who were referred for PJI between 2004 and 2014, we retrospectively studied 160 patients (163 TKAs) who had a minimum of 2 years of followup after surgical treatment or had failure of treatment within 2 years. Nineteen TKAs (19 patients) were excluded from the study; 13 patients (7%) had < 2-year followup, three patients had infected periprosthetic fractures, and three patients had infected extensor mechanism reconstruction. Eighty-six patients (88 TKAs, two bilateral [54%]) had no surgical treatment before referral to our institution for PJI management, and 75 patients (75 TKAs [46%]) had PJI surgery before referral. The mean followup was 2.4 ± 1.2 years for patients with PJI surgery before referral and 2.8 ± 1.3 years for patients with no surgery before referral (p = 0.065). Infection-free survival was defined as prosthesis retention without further surgical intervention or antibiotic suppression. During the period, further surgical intervention generally was performed after failure of irrigation and debridement, a one- or two-stage procedure, or between stages of a two-stage reimplantation without documentation of an eradiated infection, and antibiotic suppression generally was used when patients were not medically sound for surgical intervention or definitive implants were placed after the second of a two-stage procedure with positive cultures; these criteria were applied similarly to all patients during this time period in both study groups. Endpoints were assessed using a longitudinally maintained institutional database, and the treating surgeons were not involved in data abstraction. Relative and absolute risk reductions with 95% confidence intervals (CIs) as well as a Kaplan-Meier survival curve with a Cox proportional hazard model were used to evaluate survival adjusting for significant covariates. The number needed to harm is calculated as the number needed to treat. It is the reciprocal of the absolute risk reduction or production by an intervention.RESULTS: The cumulative infection-free survival rate of TKAs at 2 years or longer was worse when PJI surgery was performed before referral to a tertiary center (80%; 95% CI, 69%-87%) compared with when no PJI surgery was performed before referral (94%; 95% CI, 87%-98%; log-rank test p = 0.006). Additionally, PJI surgery before referral resulted in a lower likelihood of causative microorganism identification (52 of 75 [69%]) compared with patients having surgery at the tertiary center (77 of 88 [88%]; odds ratio, 2.71; 95% CI, 1.28-4.70; p = 0.006). With regard to the infection-free survival rate of TKAs, the number needed to harm was 7.0 (95% CI, 4.1-22.5), meaning the referral of less than seven patients to a tertiary care center for definitive surgical management of PJI before intervention at the referring hospital prevents one infection-related failure. With regard to the culture negativity in PJI, the number needed to harm was 5.5 (95% CI, 3.3-16.7), meaning the referral of less than six patients to a tertiary care institution for PJI before surgery at the outside hospital prevents the diagnosis of one culture-negative infection.CONCLUSIONS: Surgical treatment of a PJI before referral for subspecialty surgical management increases the risk of failure of subsequent surgical management. The prevalence of culture-negative PJI was much higher if surgery was attempted before referral to a tertiary care center when compared with referral before treatment. This suggests that surgical treatment of PJI before referral to a treating center with specialized expertise in PJI compromises the infection-free survival and impacts infecting organism isolation.LEVEL OF EVIDENCE: Level III, therapeutic study.

  View details for DOI 10.1097/CORR.0000000000000423

  View details for PubMedID 30179927

• Headless Compression Screw Fixation of Vertical Medial Malleolus Fractures is Superior to Unicortical Screw Fixation. American journal of orthopedics (Belle Mead, N.J.) Wegner, A. M., Wolinsky, P. R., Robbins, M. A., Garcia, T. C., Maitra, S., Amanatullah, D. F. 2018; 47 (8)

  Abstract

  This study is the first biomechanical research of headless compression screws for fixation of vertical shear fractures of the medial malleolus, a promising alternative that potentially offers several advantages for fixation. Vertical shear fractures were simulated by osteotomies in 20 synthetic distal tibiae. Models were randomly assigned to fixation with either 2 parallel cancellous screws or 2 parallel Acutrak 2 headless compression screws (Acumed). Specimens were subjected to offset axial loading to simulate supination-adduction loading and tracked using high-resolution video. The headless compression screw construct was significantly stiffer (P < .0001) (360 ± 131 N/mm) than the partially threaded cancellous screws (180 ± 48 N/mm) and demonstrated a significantly increased (P < .0001) mean load to clinical failure (719 ± 91 N vs 343 ± 83 N). When specimens were displaced to 6 mm and allowed to relax, the headless compression screw constructs demonstrated an elastic recoil and were reduced to the pretesting fragment alignment, whereas the parallel cancellous screw constructs remained displaced. Along with the headless design that may decrease soft tissue irritation, the increased stiffness and elastic recoil of the headless compression screw construct offers improved fixation of medial malleolus vertical shear fractures over the traditional methods.

  View details for DOI 10.12788/ajo.2018.0066

  View details for PubMedID 30180221

• Financial Distress and Discussing the Cost of Total Joint Arthroplasty. The Journal of arthroplasty Amanatullah, D. F., Murasko, M. J., Chona, D. V., Crijns, T. J., Ring, D., Kamal, R. N. 2018

  Abstract

  BACKGROUND: Total joint arthroplasty is expensive. Out-of-pocket cost to patients undergoing elective total joint arthroplasty varies considerably depending on their insurance coverage but can range into the tens of thousands of dollars. The goal of this study is to evaluate the association between patient financial stress and interest in discussing costs associated with surgery.METHODS: One hundred forty-one patients undergoing elective total hip and knee arthroplasty at a suburban academic medical center were enrolled and completed questionnaires about cost prior to surgery. Questions regarding if and when doctors should discuss the cost of healthcare with patients, evaluating if patients were affected by the cost of healthcare and to what extent, and financial security scores to assess current financial situation were included. The primary outcome was the answer to the question of whether a doctor should discuss cost with patients.RESULTS: Financial stress was found to be associated with patient experience of hardship due to cost of care [P= .004], likelihood to turn down a test or treatment due to copayment [P= .029], to decline a test or treatment due to other costs [P= .003], to experience difficulty affording basic necessities [P= .008], and to have used up all or most of their savings to pay for surgery [P= .011]. In total, 84% of patients reported that they wanted to discuss surgical costs with their doctors, but 90% did not want to do so at every visit.CONCLUSION: Total joint arthroplasty creates considerable out-of-pocket costs that may affect patient decisions. These findings help elucidate important patient concerns that orthopedic surgeons should account for when discussing elective arthroplasty with patients.

  View details for DOI 10.1016/j.arth.2018.07.010

  View details for PubMedID 30057266

• Effect of Computer Navigation on Complication Rates Following Unicompartmental Knee Arthroplasty. The Journal of arthroplasty Chona, D., Bala, A., Huddleston, J. I., Goodman, S. B., Maloney, W. J., Amanatullah, D. F. 2018

  Abstract

  BACKGROUND: We evaluated whether the complication and revision rates of unicompartmental knee arthroplasty (UKA) performed with intraoperative computer-based navigation differ from standard UKAs performed without intraoperative computer-based navigation.METHODS: A Medicare database containing administrative claims data from 2005 to 2014 was queried. Patients who underwent a single UKA and had a minimum of 2 years of follow-up were included in the study. Data from 1025 UKAs performed with navigation were compared against 9228 age and gender-matched UKAs performed without it. Postoperative complications were identified using International Classification of Diseases, Ninth Revision, codes and evaluated at 30 days, 90 days, and 2 years.RESULTS: Orthopedic complications after UKA are rare, and the use of navigation did not affect the rate of conversion to total knee arthroplasty at 2-year follow-up (3.8% in navigated UKAs vs 4.7% in standard UKAs, P= .218). There were also no significant differences in the rates of knee arthrotomy at 2-year follow-up (1.3% in navigated UKAs vs 1.6% in standard UKAs, P= .379). The rates of deep vein thrombosis at 90-day follow-up did not significantly differ between the 2 groups (1.4% in navigated UKAs vs 2.0% in standard UKAs, P= .157).CONCLUSION: This is one of the first studies to use a large cohort to compare outcomes in computer-assisted surgery-UKA against standard UKAs without navigation. The results, particularly that there was not a difference in the rate of conversion to total knee arthroplasty, are directly relevant to clinical decision-making when surgeons are considering employing navigation during UKA.

  View details for DOI 10.1016/j.arth.2018.06.030

  View details for PubMedID 30033063

• Patient Perceptions Correlate Weakly With Observed Patient Involvement in Decision-making in Orthopaedic Surgery. Clinical orthopaedics and related research Mertz, K., Eppler, S., Yao, J., Amanatullah, D. F., Chou, L., Wood, K. B., Safran, M., Steffner, R., Gardner, M., Kamal, R. 2018

  Abstract

  BACKGROUND: Shared decision-making between patients and physicians involves educating the patient, providing options, eliciting patient preferences, and reaching agreement on a decision. There are different ways to measure shared decision-making, including patient involvement, but there is no consensus on the best approach. In other fields, there have been varying relationships between patient-perceived involvement and observed patient involvement in shared decision-making. The relationship between observed and patient-perceived patient involvement in decision-making has not been studied in orthopaedic surgery.QUESTIONS/PURPOSES: (1) Does patient-perceived involvement correlate with observed measurements of patient involvement in decision-making in orthopaedic surgery? (2) Are patient demographics associated with perceived and observed measurements of patient involvement in decision-making?METHODS: We performed a prospective, observational study to compare observed and perceived patient involvement in new patient consultations for eight orthopaedic surgeons in subspecialties including hand/upper extremity, total joint arthroplasty, spine, sports, trauma, foot and ankle, and tumor. We enrolled 117 English-literate patients 18 years or older over an enrollment period of 2 months. A member of the research team assessed observed patient involvement during a consultation with the Observing Patient Involvement in Decision-Making (OPTION) instrument (scaled 1-100 with higher scores representing greater involvement). After the consultation, we asked patients to complete a questionnaire with demographic information including age, sex, race, education, income, marital status, employment status, and injury type. Patients also completed the Perceived Involvement in Care Scale (PICS), which measures patient-perceived involvement (scaled 1-13 with higher scores representing greater involvement). Both instruments are validated in multiple studies in various specialties and the physicians were blinded to the instruments used. We assessed the correlation between observed and patient-perceived involvement as well as tested the association between patient demographics and patient involvement scores.RESULTS: There was weak correlation between observed involvement (OPTION) and patient-perceived involvement (PICS) (r = 0.37, p < 0.01) in decision-making (mean OPTION, 28.7, SD 7.7; mean PICS, 8.43, SD 2.3). We found a low degree of observed patient involvement despite a moderate to high degree of perceived involvement. No patient demographic factor had a significant association with patient involvement.CONCLUSIONS: Further work is needed to identify the best method for evaluating patient involvement in decision-making in the setting of discordance between observed and patient-perceived measurements. Knowing whether it is necessary for (1) actual observable patient involvement to occur; or (2) a patient to simply believe they are involved in their care can inform physicians on the best way to improve shared decision-making in their practice.LEVEL OF EVIDENCE: Level II, therapeutic study.

  View details for DOI 10.1097/CORR.0000000000000365

  View details for PubMedID 29965894

• Headless compression screw for horizontal medial malleolus fractures. Clinical biomechanics (Bristol, Avon) Cheng, R. Z., Wegner, A. M., Behn, A. W., Amanatullah, D. F. 2018; 55: 1–6

  Abstract

  BACKGROUND: Horizontal medial malleolus fractures are caused by the application of rotational force through the ankle joint in several orientations. Multiple techniques are available for the fixation of medial malleolar fractures.METHODS: Horizontal medial malleolus osteotomies were performed in eighteen synthetic distal tibiae and randomized into two fixation groups: 1) two parallel unicortical cancellous screws or 2) two Acutrak 2 headless compression screws. Specimens were subjected to offset axial tension loading. Frontal plane interfragmentary motion was monitored.FINDINGS: The headless compression group (1699 (SD 947) N/mm) had significantly greater proximal-distal stiffness than the unicortical group (668 (SD 298) N/mm), (P = 0.012). Similarly, the headless compression group (604 (SD 148) N/mm) had significantly greater medial-lateral stiffness than the unicortical group (281 (SD 152) N/mm), (P < 0.001). The force at 2 mm of lateral displacement was significantly greater in the headless compression group (955 (SD 79) N) compared to the unicortical group (679 (SD 198) N), (P = 0.003). At 2 mm of distal displacement, the mean force was higher in the headless compression group (1037 (SD 122) N) compared to the unicortical group (729 (SD 229) N), but the difference was not significant (P = 0.131).INTERPRETATION: A headless compression screw construct was significantly stiffer in both the proximal-distal and medial-lateral directions, indicating greater resistance to both axial and shear loading. Additionally, they had significantly greater load at clinical failure based on lateral displacement. The low-profile design of the headless compression screw minimizes soft tissue irritation and reduces need for implant removal.

  View details for DOI 10.1016/j.clinbiomech.2018.03.023

  View details for PubMedID 29604557

• Protocol-Driven Revision for Stiffness After Total Knee Arthroplasty Improves Motion and Clinical Outcomes. The Journal of arthroplasty Hug, K. T., Amanatullah, D. F., Huddleston, J. I., Maloney, W. J., Goodman, S. B. 2018

  Abstract

  BACKGROUND: Stiffness after revision total knee arthroplasty (TKA) is a difficult problem without a well-defined treatment algorithm. The purpose of this study was to evaluate the results of revision TKA for stiffness within the context of differential component replacement.METHODS: Consecutive patients who underwent revision TKA were retrospectively identified and included those who received debridement and polyethylene liner exchange alone, revision of only one of the femoral or tibial fixed components, or revision of all components. Preoperative and postoperative range of motion and Knee Society score (KSS) were collected.RESULTS: Sixty-nine knees were included in the study group with a mean follow-up of 43 months (range, 12-205 months). The mean prerevision flexion contracture of 17° improved to 5° after surgical intervention (P < .001). Similarly, mean flexion and motion arc improved from 70° to 92° and from 53° to 87°, respectively (P < .001). Mean KSS knee scores improved from 42 to 70 and KSS function scores improved from 41 to 68 (P < .001). Mean arc of motion improved by 45° in patients who underwent complete component revision, 32° with component retention, and 29° with single component revision (P= .046). KSS knee scores improved by 34, 25, and 28 points in these respective groups (P= .049). KSS function scores improved by 33, 27, and 25 points (P= .077).CONCLUSION: Revision surgery with or without component revision can improve motion and function in patients with stiffness after TKA. Complete component revision may offer the largest improvements in these outcome measures in properly selected patients.

  View details for DOI 10.1016/j.arth.2018.05.013

  View details for PubMedID 29859726

• Mini-Fragment Fixation Is Equivalent to Bicortical Screw Fixation for Horizontal Medial Malleolus Fractures ORTHOPEDICS Wegner, A. M., Wolinsky, P. R., Robbins, M. A., Garcia, T. C., Amanatullah, D. F. 2018; 41 (3): E395–E399

  Abstract

  Horizontal fractures of the medial malleolus occur through application of valgus or abduction force through the ankle that creates a tension failure of the medial malleolus. The authors hypothesize that mini-fragment T-plates may offer improved fixation, but the optimal fixation construct for these fractures remains unclear. Forty synthetic distal tibiae with identical osteotomies were randomized into 4 fixation constructs: (1) two parallel unicortical cancellous screws; (2) two parallel bicortical cortical screws; (3) a contoured mini-fragment T-plate with 2 unicortical screws in the fragment and 2 bicortical screws in the shaft; and (4) a contoured mini-fragment T-plate with 2 bicortical screws in the fragment and 2 unicortical screws in the shaft. Specimens were subjected to offset axial tension loading on a servohydraulic testing system and tracked using high-resolution video. Failure was defined as 2 mm of articular displacement. Analysis of variance followed by a Tukey-Kramer post hoc test was used to assess for differences between groups, with significance defined as P<.05. The mean stiffness (±SD) values of both mini-fragment T-plate constructs (239±83 N/mm and 190±37 N/mm) and the bicortical screw construct (240±17 N/mm) were not statistically different. The mean stiffness values of both mini-fragment T-plate constructs and the bicortical screw construct were higher than that of a parallel unicortical screw construct (102±20 N/mm). Contoured T-plate constructs provide stiffer initial fixation than a unicortical cancellous screw construct. The T-plate is biomechanically equivalent to a bicortical screw construct, but may be superior in capturing small fragments of bone. [Orthopedics. 2018; 41(3):e395-e399.].

  View details for DOI 10.3928/01477447-20180409-03

  View details for Web of Science ID 000432834800016

  View details for PubMedID 29658979

• Risk Reduction Compared with Access to Care: Quantifying the Trade-Off of Enforcing a Body Mass Index Eligibility Criterion for Joint Replacement JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME Giori, N. J., Amanatullah, D. F., Gupta, S., Bowe, T., Harris, A. 2018; 100 (7): 539–45

  Abstract

  Morbidly obese patients with severe osteoarthritis benefit from successful total joint arthroplasty. However, morbid obesity increases the risk of complications. Because of this, some surgeons enforce a body mass index (BMI) eligibility criterion above which total joint arthroplasty is denied. In this study, we investigate the trade-off between avoiding complications and restricting access to care when enforcing BMI-based eligibility criteria for total joint arthroplasty.In this retrospective cohort study, the Veterans Health Administration (VHA) Corporate Data Warehouse (CDW) and Veterans Affairs Surgical Quality Improvement Program (VASQIP) databases were reviewed for patients undergoing total joint arthroplasty from October 2011 through September 2014. We determined, if various BMI eligibility criteria had been enforced over that period of time, how many short-term complications would have been avoided, how many complication-free surgical procedures would have been denied, and the positive predictive value of BMI eligibility criteria as tests for major complications. To provide a frame of reference, we also determined what would have happened if eligibility for total joint arthroplasty were arbitrarily determined by flipping a coin.In this study, 27,671 total joint arthroplasties were reviewed. With a BMI criterion of ≥40 kg/m, 1,148 patients would have been denied a surgical procedure free of major complications, and 83 patients would have avoided a major complication. The positive predictive value of a complication using a BMI of ≥40 kg/m as a test for major complications was 6.74% (95% confidence interval [CI], 5.44% to 8.33%). The positive predictive value of a complication using a BMI criterion of 30 kg/m was 5.33% (95% CI, 4.99% to 5.71%). Flipping a coin had a positive predictive value of 5.05%.A 30 kg/m criterion for total joint arthroplasty eligibility is marginally better than flipping a coin and should not determine surgical eligibility. With a BMI criterion of ≥40 kg/m, the number of patients denied a complication-free surgical procedure is about 14 times larger than those spared a complication. Although the acceptable balance between avoiding complications and providing access to care can be debated, such a quantitative assessment helps to inform decisions regarding the advisability of enforcing a BMI criterion for total joint arthroplasty.Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

  View details for DOI 10.2106/JBJS.17.00120

  View details for Web of Science ID 000437284600008

  View details for PubMedID 29613922

  View details for PubMedCentralID PMC5895162

• Obesity Is Independently Associated With Early Aseptic Loosening in Primary Total Hip Arthroplasty JOURNAL OF ARTHROPLASTY Goodnough, L. H., Finlay, A. K., Huddleston, J. I., Goodman, S. B., Maloney, W. J., Amanatullah, D. F. 2018; 33 (3): 882–86

  Abstract

  Obesity affects millions of patients in the United States and is associated with several complications after total hip arthroplasty (THA). The effect of obesity on the rate and mode of primary THA failure remains poorly understood, especially given other potentially confounding patient characteristics. We hypothesized that, among patients with a failed primary THA, obesity is independently associated with aseptic loosening and a higher rate of early revision.Six hundred eighty-four consecutive cases with failed THA referred to a single academic center for revision during a 10-year period were retrospectively reviewed. Multivariate logistic regression analysis was used to test the independent association between obesity and the timing as well as cause of THA failure.The rate of primary THA failure before 5 years was 48.8% in obese and 37.1% in nonobese patients (odds ratio [OR] = 1.57, P = .010). Primary THA failure before 5 years was more likely with increasing body mass index (BMI) (BMI: 35-40 kg/m2, OR = 2.31, P = .008; BMI >40 kg/m2, OR = 2.51, P = .049). The rate of primary THA failure for aseptic loosening before 5 years was 30% in obese and 18% in nonobese patients (OR = 1.88, P = .023). Obesity was not a risk for revision for infection, whereas an American Society of Anesthesiologists class ≥3 was independently associated with primary THA failure for infection (OR = 2.33, P < .001).Among patients with a failed THA, comorbidities may account for the risk of revision due to infection in obese patients. Obesity is independently associated with early primary THA failure for aseptic loosening.

  View details for DOI 10.1016/j.arth.2017.09.069

  View details for Web of Science ID 000425893000046

  View details for PubMedID 29089226

• Implant-Associated Bacterial Biofilm and Quorum Sensing in Periprosthetic Joint Infections. Journal of orthopaedic research : official publication of the Orthopaedic Research Society Mooney, J. A., Pridgen, E. M., Manasherob, R., Suh, G., Blackwell, H. E., Barron, A. E., Bollyky, P. L., Goodman, S. B., Amanatullah, D. F. 2018

  Abstract

  Periprosthetic joint infection (PJI) continues to be a common complication after total knee arthroplasty and total hip arthroplasty leading to severe morbidity and mortality. With an aging population and increasing prevalence of total joint replacement procedures, the burden of PJI will be felt not only by individual patients, but in increased healthcare costs. Current treatment of PJI is inadequate resulting in incredibly high failure rates. This is believed to be largely mediated by the presence of bacterial biofilms. These polymicrobial bacterial colonies form within secreted extracellular matrices, adhering to the implant surface and local tissue. The biofilm architecture is believed to play a complex and critical role in a variety of bacterial processes including nutrient supplementation, metabolism, waste management, and antibiotic and immune resistance. The establishment of these biofilms relies heavily on the quorum sensing communication systems utilized by bacteria. Early stage research into disrupting bacterial communication by targeting quorum sensing show promise for future clinical applications. However, prevention of the biofilm formation via early forced induction of the biofilm forming process remains yet unexplored. This article is protected by copyright. All rights reserved.

  View details for DOI 10.1002/jor.24019

  View details for PubMedID 29663554

• Outcome of 4 Surgical Treatments for Wear and Osteolysis of Cementless Acetabular Components (vol 32, pg 2799, 2017) JOURNAL OF ARTHROPLASTY Narkbunnam, R., Amanatullah, D. F., Electricwala, A. J., Huddleston, J. I., Maloney, W. J., Goodman, S. B. 2018; 33 (1): 308

  View details for DOI 10.1016/j.arth.2017.10.001

  View details for Web of Science ID 000418761100061

• Continuous Femoral Nerve Catheters Decrease Opioid-Related Side Effects and Increase Home Disposition Rates Among Geriatric Hip Fracture Patients. Journal of orthopaedic trauma Arsoy, D., Gardner, M. J., Amanatullah, D. F., Huddleston, J. I., Goodman, S. B., Maloney, W. J., Bishop, J. A. 2017; 31 (6): e186-e189

  Abstract

  To evaluate the effect of continuous femoral nerve catheter (CFNC) for postoperative pain control in geriatric proximal femur fractures compared with standard analgesia (SA) treatment.Retrospective comparative study.Academic Level 1 trauma center.We retrospectively identified 265 consecutive geriatric hip fracture patients who underwent surgical treatment.One hundred forty-nine patients were treated with standard analgesia without nerve catheter whereas 116 patients received an indwelling CFNC.Daily average preoperative and postoperative pain scores, daily morphine equivalent consumption, opioid-related side effects and discharge disposition.Patients with CFNC patients reported lower average pain scores preoperatively (1.9 ± 1.7 for CFNC vs. 4.7 ± 2 for SA; P < 0.0001), on postoperative day 1 (1.5 ± 1.6 for CFNC vs. 3 ± 1.7 for SA; P < 0.0001) and postoperative day 2 (1.2 ± 1.5 for CFNC vs. 2.6 ± 2.1 for SA; P < 0.0001). CFNC group consumed 39% less morphine equivalents on postoperative day 1 (4.4 ± 5.8 mg for CFNC vs. 7.2 ± 10.8 mg for SA; P = 0.005) and 50% less morphine equivalent on postoperative day 2 (3.4 ± 4.4 mg for CFNC vs. 6.8 ± 13 mg for SA; P = 0.105). Patients with CFNC had a lower rate of opioid-related side effects compared with patients with SA (27.5% for CFNC vs. 47% for SA; P = 0.001). More patients with CFNC were discharged to home with or without health services than patients with SA (15% for CFNC vs. 6% for SA; P = 0.023).Continuous femoral nerve catheter decreased daily average patient-reported pain scores, narcotic consumption while decreasing the rate of opioid-related side effects. Patients with CFNC were discharged to home more frequently.Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

  View details for DOI 10.1097/BOT.0000000000000854

  View details for PubMedID 28538458

• Venous Thromboembolism Prophylaxis After TKA: Aspirin, Warfarin, Enoxaparin, or Factor Xa Inhibitors? Clinical orthopaedics and related research Bala, A., Huddleston, J. I., Goodman, S. B., Maloney, W. J., Amanatullah, D. F. 2017

  Abstract

  There is considerable debate regarding the ideal agent for venous thromboembolism (VTE) prophylaxis after TKA. Numerous studies and meta-analyses have yet to provide a clear answer and often omit one or more of the commonly used agents such as aspirin, warfarin, enoxaparin, and factor Xa inhibitors.Using a large database analysis, we asked: (1) What are the differences in VTE incidence in primary TKA after administration of aspirin, warfarin, enoxaparin, or factor Xa inhibitors? (2) What are the differences in bleeding risk among these four agents? (3) How has use of these agents changed with time?We queried a combined Humana and Medicare database between 2007 and Quarter 1 of 2016, and identified all primary TKAs performed using ICD-9 and Current Procedural Terminology codes. All patients who had any form of antiplatelet or anticoagulation prescribed within 1 year before TKA were excluded from our study cohort. We then identified patients who had either aspirin, warfarin, enoxaparin, or factor Xa inhibitors prescribed within 2 weeks of primary TKA. Each cohort was matched by age and sex. Elixhauser comorbidities and Charlson Comorbidity Index for each group were calculated. We identified 1016 patients with aspirin, and age- and sex-matched 6096 patients with enoxaparin, 6096 patients with warfarin, and 5080 patients with factor Xa inhibitors. Using ICD-9 codes, with the understanding that patients at greater risk may have had more-attentive surveillance, the incidence of postoperative deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding-related complications (bleeding requiring surgical intervention, hemorrhage, hematoma, hemarthrosis), postoperative anemia, and transfusion were identified at 2 weeks, 30 days, 6 weeks, and 90 days postoperatively. A four-way chi-squared test was used to determine statistical significance. Utilization was calculated using compound annual growth rate.There was a difference in the incidence of DVT at 90 days (p < 0.01). Factor Xa inhibitors (2.9%) had the lowest incidence of DVT followed by aspirin (3.0%) and enoxaparin (3.5%), and warfarin (4.8%). There was a difference in the incidence of PE at 90 days (p < 0.01). Factor Xa inhibitors (0.9%) had the lowest incidence of PE followed by enoxaparin (1.1%), aspirin (1.2%), and warfarin (1.6%). There was a difference in the incidence of postoperative anemia at 90 days (p < 0.01). Aspirin (19%) had the lowest incidence of postoperative anemia followed by warfarin (22%), enoxaparin (23%), and factor Xa inhibitors (23%). There was a difference in the incidence of a blood transfusion at 90 days (p < 0.01). Aspirin (7%) had the lowest incidence of a blood transfusion followed by factor Xa inhibitors (9%), warfarin (12%), and enoxaparin (13%). There were no differences in bleeding-related complications (p = 0.81) between the groups. Aspirin use increased at a compound annual growth rate of 30%, enoxaparin at 3%, and factor Xa inhibitors at 43%, while warfarin use decreased at a compound annual growth rate of -3%.Factor Xa inhibitors had the highest growth in utilization during our study period, followed by aspirin, when compared with enoxaparin and warfarin. When selected for the right patient, factor Xa inhibitors provided improved VTE prophylaxis compared with enoxaparin and warfarin, with a lower rate of blood transfusion. Aspirin provided comparable VTE prophylaxis compared with factor Xa inhibitors with improved VTE prophylaxis compared with enoxaparin and warfarin with the lowest risk of bleeding.Level III, therapeutic study.

  View details for DOI 10.1007/s11999-017-5394-6

  View details for PubMedID 28569372

• Radiographic scoring system for the evaluation of stability of cementless acetabular components in the presence of osteolysis BONE & JOINT JOURNAL Narkbunnam, R., Amanatullah, D. F., Electricwala, A. J., Huddleston, J. I., Maloney, W. J., Goodman, S. B. 2017; 99-B (5): 601-606

  Abstract

  The stability of cementless acetabular components is an important factor for surgical planning in the treatment of patients with pelvic osteolysis after total hip arthroplasty (THA). However, the methods for determining the stability of the acetabular component from pre-operative radiographs remain controversial. Our aim was to develop a scoring system to help in the assessment of the stability of the acetabular component under these circumstances.The new scoring system is based on the mechanism of failure of these components and the location of the osteolytic lesion, according to the DeLee and Charnley classification. Each zone is evaluated and scored separately. The sum of the individual scores from the three zones is reported as a total score with a maximum of 10 points. The study involved 96 revision procedures which were undertaken for wear or osteolysis in 91 patients between July 2002 and December 2012. Pre-operative anteroposterior pelvic radiographs and Judet views were reviewed. The stability of the acetabular component was confirmed intra-operatively.Intra-operatively, it was found that 64 components were well-fixed and 32 were loose. Mean total scores in the well-fixed and loose components were 2.9 (0 to 7) and 7.2 (1 to 10), respectively (p < 0.001). In hips with a low score (0 to 2), the component was only loose in one of 33 hips (3%). The incidence of loosening increased with increasing scores: in those with scores of 3 and 4, two of 19 components (10.5%) were loose; in hips with scores of 5 and 6, eight of 19 components (44.5%) were loose; in hips with scores of 7 or 8, 13 of 17 components (70.6%) were loose; and for hips with scores of 9 and 10, nine of nine components (100%) were loose. Receiver-operating-characteristic curve analysis demonstrated very good accuracy (area under the curve = 0.90, p < 0.001). The optimal cutoff point was a score of ≥ 5 with a sensitivity of 0.79, and a specificity of 0.87.There was a strong correlation between the scoring system and the probability of loosening of a cementless acetabular component. This scoring system provides a clinically useful tool for pre-operative planning, and the evaluation of the outcome of revision surgery for patients with loosening of a cementless acetabular component in the presence of osteolysis. Cite this article: Bone Joint J 2017;99-B:601-6.

  View details for DOI 10.1302/0301-620X.99B5.BJJ-2016-0968.R1

  View details for Web of Science ID 000400306700007

  View details for PubMedID 28455468

• Cortical Strut Allograft Support of Modular Femoral Junctions During Revision Total Hip Arthroplasty JOURNAL OF ARTHROPLASTY Lim, C. T., Amanatullah, D. F., Huddleston, J. I., Hwang, K. L., Maloney, W. J., Goodman, S. B. 2017; 32 (5): 1586-1592

  Abstract

  There is risk of junction failure when using modular femoral stems for revision total hip arthroplasty (THA), especially with loss of bone stock in the proximal femur. Using a cortical strut allograft may provide additional support of a modular femoral construct in revision THA.We reviewed prospectively gathered clinical and radiographic data for 28 revision THAs performed from 2004 to 2014 using cementless modular femoral components with cortical strut allograft applied to supplement proximal femoral bone loss: 5 (18%) were fluted taper designs and 23 (82%) were porous cylindrical designs All the patients had a Paprosky grade IIIA or greater femoral defect. The mean follow-up was 5.4 ± 3.9 years.The Harris Hip Scores improved from 26 ± 10 points preoperatively to 71 ± 10 points at final follow-up (P < .001). The Western Ontario McMaster Universities Osteoarthritis Index scores improved from 45 ± 12 points preoperatively to 76 ± 12 points at final follow-up (P < .001). Eighty-nine percent (25 hips) of all revision or conversion THAs were in place at final follow-up. Three (11%) patients underwent reoperations, 2 for infection and 1 for periprosthetic fracture. There was no statistical significant change in femoral component alignment (P = .161) at final follow-up. Mean subsidence was 1.8 ± 1.3 mm at final follow-up. Femoral diameter increased from initial postoperative imaging to final follow-up imaging by a mean of 9.1 ± 5.1 mm (P < .001) and cortical width increased by a mean of 4.5 ± 2.2 mm (P < .001). Twenty-seven hips (96%) achieved union between the cortical strut allograft and the host femur.The use of a modular femoral stem in a compromised femur with a supplementary cortical strut allgraft is safe and provides satisfactory clinical and radiological outcomes.

  View details for DOI 10.1016/j.arth.2016.12.011

  View details for Web of Science ID 000401132100033

• Use of Cortical Strut Allograft After Extended Trochanteric Osteotomy in Revision Total Hip Arthroplasty JOURNAL OF ARTHROPLASTY Lim, C. T., Amanatullah, D. F., Huddleston, J. I., Hwang, K. L., Maloney, W. J., Goodman, S. B. 2017; 32 (5): 1599-1605

  Abstract

  Cortical strut allografts restore bone stock and improve postoperative clinical scores after revision total hip arthroplasty (THA). However, use of a cortical strut allograft is implicated in delayed healing of an extended trochanteric osteotomy (ETO). To date, there are no reports directly comparing ETO with or without cortical strut allografts.We reviewed prospectively gathered data on 50 revision THAs performed from 2004-2014 using an ETO. We compared the demographic, radiological, and clinical outcome of patients with (16 hips) and without (34 hips) cortical strut allograft after an ETO.There were no significant differences in Western Ontario McMaster Universities Osteoarthritis Index or Harris Hip Score between the ETOs with and without a cortical strut allograft. Fifteen of the ETOs (94%) with a cortical strut allograft and 31 of the ETOs (91%) without a cortical strut allograft were in situ at final follow-up (P = 1.000). A higher proportion hips with cortical strut allograft (100%, 16 patients) had preoperative Paprosky grade bone loss more than IIIA compared to those without allograft (29%, 10 patients) (P < .001). There were no differences in femoral stem subsidence (P = .207), alignment (P = .934), or migration of the osteotomized fragment (P = .171). Fourteen of the ETOs (88%) in patients with cortical strut allograft united compared to 34 ETOs (100%) in patients without allograft (P = .095).Our study shows that the use of cortical strut allograft during revision THA with ETO does not reduce the rate of union, radiological or clinical outcomes.

  View details for DOI 10.1016/j.arth.2016.12.002

  View details for Web of Science ID 000401132100035

• Outcome of 4 Surgical Treatments for Wear and Osteolysis of Cementless Acetabular Components. journal of arthroplasty Narkbunnam, R., Amanatullah, D. F., Electriwala, A. J., Huddleston, J. I., Maloney, W. J., Goodman, S. B. 2017

  Abstract

  Loosening and periprosthetic osteolysis are some of the most common long-term complications after hip arthroplasty. The decision-making process and surgical treatment options are controversial.We retrospectively reviewed 96 acetabular revisions (91 patients) performed between 2002 and 2012, with a minimum of 2 years of follow-up and a mean of 5.7 years of follow-up. Clinical outcome was assessed using the Harris Hip Score. The size and location of osteolytic lesions were evaluated using the preoperative radiographs; healing of the defects was categorized using a standardized protocol.Thirty-three (34.4%) hips had isolated liner exchanges (ILEs), 10 (10.4%) hips had cemented liners into well-fixed shells (CLS), 45 (46.9%) hips had full acetabular revisions (FARs), and 8 (8.3%) hips had revision with a roof ring/antiprotrusio cage (RWC). All procedures showed significant improvement in Harris Hip Score after revision (P ≤ .001). Fifteen patients had moderate residual pain (pain score ≤20): 8 (24%) ILE, 3 (30%) CLS, and 4 (9%) FAR. Complete bone defect healing after grafting was lower with acetabular component retention procedures (ILE and CLS; 27%) compared with full acetabular component revision procedures (FAR and RWC; 57%). Fifteen patients underwent reoperation: 3 ILE, 1 CLS, 8 FAR, and 3 RWC.Acetabular component retention demonstrates a low risk of reoperation; however, residual pain and limited potential for bone graft incorporation are a concern. FAR is technically challenging and may have an elevated risk of reoperation; however, higher degrees of bone graft incorporation and satisfactory clinical outcome can be expected.

  View details for DOI 10.1016/j.arth.2017.04.028

  View details for PubMedID 28587888

• The Direct Anterior Approach is Associated With Early Revision Total Hip Arthroplasty. journal of arthroplasty Eto, S., Hwang, K., Huddleston, J. I., Amanatullah, D. F., Maloney, W. J., Goodman, S. B. 2017; 32 (3): 1001-1005

  Abstract

  The direct anterior approach for total hip arthroplasty (THA) has generated increased interest recently. The purpose of this study was to compare the duration to failure and reasons for revision of primary THA performed elsewhere and subsequently revised at our institution after the direct anterior vs other nonanterior surgical approaches to the hip.All primary THAs performed elsewhere and referred to our institution for revision were divided into the direct anterior approach (30 cases) or nonanterior approach groups (100 cases, randomly selected from 453 cases) based on the original surgical approach. Because all primary direct anterior THAs were originally performed after 2004 to eliminate temporal bias, we identified a subset of the nonanterior group in which the primary THA was performed after 2004 (known as the recent nonanterior group, 100 cases, randomly selected from 169 available cases).The mean duration from primary to revision THA was 3.0 ± 2.7 years (direct anterior approach), 12.0 ± 8.8 years (nonanterior approach), and 3.6 ± 2.8 years (recent nonanterior), respectively. There was a significant difference in time to revision between the direct anterior and nonanterior approach groups (P < .001). Aseptic loosening of the stem was significantly more frequent with the direct anterior approach group (9/30, 30.0%) when compared with the nonanterior group (8/100, 8.0%, P = .007) and the recent nonanterior group (7/100, 7.0%, P = .002).Revision of the femoral component for aseptic loosening is more commonly associated with the direct anterior approach in our referral practice.

  View details for DOI 10.1016/j.arth.2016.09.012

  View details for PubMedID 27843039

• Revision Total Hip Arthroplasty Using the Cement-in-Cement Technique ORTHOPEDICS Amanatullah, D. F., Pallante, G. D., Floccari, L. V., Vasileiadis, G. I., Trousdadale, R. T. 2017; 40 (2): E348-E351

  View details for DOI 10.3928/01477447-20161213-05

  View details for Web of Science ID 000397587200023

• Revision Total Hip Arthroplasty Using the Cement-in-Cement Technique. Orthopedics Amanatullah, D. F., Pallante, G. D., Floccari, L. V., Vasileiadis, G. I., Trousdale, R. T. 2017; 40 (2): e348-e351

  Abstract

  The cement-in-cement technique is useful in the setting of revision total hip arthroplasty (THA), especially to gain acetabular exposure, change a damaged or loose femoral component, or change the version, offset, or length of a fixed femoral component. The goal of this retrospective study was to assess the clinical and radiographic characteristics of revision THA using the cement-in- cement technique. Between 1971 and 2013, a total of 63 revision THAs used an Omnifit (Osteonics, Mahwah, New Jersey) or Exeter (Howmedica, Mahwah, New Jersey) stem and the cement-in-cement technique at the senior author's institution. Aseptic loosening (74%) was the predominant preoperative diagnosis followed by periprosthetic fracture (14%), instability (8%), and implant fracture (6%). Mean clinical follow-up was 5.5±3.8 years. The Harris Hip Score had a statistically significant increase of 18.5 points (P<.001) after revision THA using the cement-in-cement technique. There were 13 returns to the operating room, resulting in an overall failure rate of 21%. Eleven (18%) cases required revision THA, but only 1 (2%) revision THA was for aseptic removal of the femoral component. All other femoral implants had no evidence of component migration, cement mantel fracture, or circumferential lucent lines at final follow-up. The patients who underwent cement-in-cement revision THA at the senior author's institution had good restoration of function but a high complication rate. [Orthopedics. 2017; 40(2):e348-e351.].

  View details for DOI 10.3928/01477447-20161213-05

  View details for PubMedID 27992642

• Weight Gain After Primary Total Knee Arthroplasty Is Associated With Accelerated Time to Revision for Aseptic Loosening. journal of arthroplasty Lim, C. T., Goodman, S. B., Huddleston, J. I., Harris, A. H., Bhowmick, S., Maloney, W. J., Amanatullah, D. F. 2017

  Abstract

  Obesity is a major health problem worldwide and is associated with complications after total knee arthroplasty (TKA). It remains unknown whether a change in body mass index (BMI) after primary TKA affects the reasons for revision TKA or the time to revision TKA.A total of 160 primary TKAs referred to an academic tertiary center for revision TKA were retrospectively stratified according to change in BMI from the time of their primary TKA to revision TKA. The association between change in BMI and time to revision was also analyzed according to indication for revision of TKA using Pearson's chi-square test.The mean change in BMI from primary to revision TKA was 0.82 ± 3.5 kg/m(2). Maintaining a stable weight after primary TKA was protective against late revision TKA for any reason (P = .004). Patients who failed to reduce their BMI were revised for aseptic loosening earlier, at less than 5 years (P = .020), whereas those who reduced their BMI were revised later, at over 10 years (P = .004).Maintaining weight after primary TKA is protective against later revision TKA for any reason but failure to reduce weight after primary TKA is a risk factor for early revision TKA for aseptic loosening and osteolysis. Orthopedic surgeons should recommend against weight gain after primary TKA to reduce the risk of an earlier revision TKA in the event that a revision TKA is indicated.

  View details for DOI 10.1016/j.arth.2017.02.026

  View details for PubMedID 28318864

• Reproducibility and Precision of CT Scans to Evaluate Tibial Component Rotation. journal of arthroplasty Amanatullah, D. F., Ollivier, M. P., Pallante, G. D., Abdel, M. P., Clarke, H. D., Mabry, T. M., Taunton, M. J. 2017

  Abstract

  Component rotation likely plays a greater role on the survivorship and outcomes of total knee arthroplasties than is currently known. Our goal was to evaluate the precision, interobserver reliability, and intrarater reliability of tibial component rotation as measured by computed tomography (CT) scan, regardless of measurement technique.Three fellowship-trained, academic arthroplasty surgeons independently measured tibial component rotation on CT scans of 62 total knee arthroplasties using their methods of choice. Measurements were repeated at least 2 weeks after the initial measurement. The precision of the measurements was assessed using a formal 8-step protocol as the gold standard. Intraclass correlation coefficients (ICCs) were calculated to evaluate precision, interobserver agreement, and intrarater reliability RESULTS: The interobserver agreement between the 3 surgeons for tibial component rotation was also moderate (ICC = 0.52). The intrarater reliability of tibial rotation was excellent (ICC = 0.81). Comparison of surgeons' measurement to a validated gold standard revealed only moderate precision for tibial component rotation (ICC = 0.64).Practicing surgeons measuring tibial rotation were internally consistent, but failed to demonstrate satisfactory precision and interobserver agreement. We support the adoption of standardized criteria for the measurement of tibial component rotation on CT scans.

  View details for DOI 10.1016/j.arth.2017.01.040

  View details for PubMedID 28434699

• Sled fixation for horizontal medial malleolus fractures. Clinical biomechanics Wegner, A. M., Wolinsky, P. R., Cheng, R. Z., Robbins, M. A., Garcia, T. C., Amanatullah, D. F. 2017; 42: 92-96

  Abstract

  Horizontal fractures of the medial malleolus occur through exertion of various rotational forces on the ankle, including supination--external rotation, pronation--external rotation, and pronation-abduction. Many methods of fixation are employed for these fractures, but the optimal fixation construct remains unclear.Horizontal medial malleolus osteotomies were performed in synthetic distal tibiae and randomized into two fixation groups: 1) two parallel unicortical cancellous screws or 2) medial malleolar sled fixation. Specimens were subjected to offset axial tension loading and tracked using high-resolution video. Clinical failure was defined as 2mm of articular displacement.There were statistically significant increases in mean stiffness (127% higher, P=0.0007) and mean force to clinical failure (52% higher, P=0.0002) with the medial malleolar sled. The mean stiffness in offset tension loading was 232 (SD 83) N/mm for medial malleolar sled and 102 (SD 20) N/mm for parallel unicortical cancellous screws. The mean force to clinical failure was 595 (SD 112) N for medial malleolar sled and 392 (SD 34) N for unicortical screws. In addition, the medial malleolar sled demonstrated elastic recoil to pre-testing alignment while the unicortical screws did not.Medial malleolar sled fixation was significantly stiffer and required more force to clinical failure than parallel unicortical cancellous screws. A medial malleolar sled requires more dissection to apply surgically, but provides significantly more initial fixation strength. Additionally, a medial malleolar sled acts like a tension band in its ability to capture comminuted fragments while being low profile enough to minimize soft tissue irritation.

  View details for DOI 10.1016/j.clinbiomech.2017.01.011

  View details for PubMedID 28119205

• Response to Letter to the Editor on 'Tibiofemoral Dislocation After Total Knee Arthroplasty' JOURNAL OF ARTHROPLASTY Jethanandani, R. G., Maloney, W. J., Huddleston, J. I., Goodman, S. B., Amanatullah, D. F. 2017; 32 (2): 700-700

  View details for DOI 10.1016/j.arth.2016.10.021

  View details for Web of Science ID 000392623800062

  View details for PubMedID 27865569

• Elevated Body Mass Index Is Associated With Early Total Knee Revision for Infection JOURNAL OF ARTHROPLASTY Electricwala, A. J., Jethanandani, R. G., Narkbunnam, R., Huddleston, J. I., Maloney, W. J., Goodman, S. B., Amanatullah, D. F. 2017; 32 (1): 252-255

  Abstract

  Obesity affects over half a billion people worldwide, including one-third of men and women in the United States. Obesity is associated with higher postoperative complication rates after total knee arthroplasty (TKA). It remains unknown whether obese patients progress to revision TKA faster than nonobese patients.A total of 666 consecutive primary TKAs referred to an academic tertiary care center for revision TKA were retrospectively stratified according to body mass index (BMI), reason for revision TKA, and time from primary to revision TKA.When examining primary TKAs referred for revision TKA, increasing BMI adversely affected the mean time to revision TKA. The percent of referred TKAs revised by 5 years was 54% for a normal BMI, 64% for an overweight patient, 71% for an obese class I patient, 68% for an obese class II patient, and 73% for a morbidly obese patient. There was a significant difference in time to revision TKA between patients with normal BMI and elevated BMI (P = .005). There was a significant increase in early revision TKA for infection in patients with an elevated BMI (54%, 74/138) when compared with the normal BMI patients (24%, 8/33, P < .003, relative risk ratio = 2.3, absolute risk = 30%, number needed to treat = 3.3). There was no significant increase in acute, early, midterm, or late revision TKA for aseptic loosening and/or osteolysis, instability, stiffness, or other causes between patients with normal BMI and elevated BMI.An elevated BMI is a risk factor for early referral to a tertiary care center for revision TKA. Specifically, orthopedic surgeons should convey to overweight and obese patients that they have at least a 130% increased relative risk and a 30% absolute risk of revision TKA for an early infection if referred for revision TKA. Patient expectations and counseling as well as reimbursement should account for the greater risks when performing a TKA on patients with an elevated BMI.

  View details for DOI 10.1016/j.arth.2016.05.071

  View details for Web of Science ID 000392623000047

  View details for PubMedID 27421585

• Local estrogen axis in the human bone microenvironment regulates estrogen receptor-positive breast cancer cells. Breast cancer research : BCR Amanatullah, D. F., Tamaresis, J. S., Chu, P., Bachmann, M. H., Hoang, N. M., Collyar, D., Mayer, A. T., West, R. B., Maloney, W. J., Contag, C. H., King, B. L. 2017; 19 (1): 121

  Abstract

  Approximately 70% of all breast cancers express the estrogen receptor, and are regulated by estrogen. While the ovaries are the primary source of estrogen in premenopausal women, most breast cancer is diagnosed following menopause, when systemic levels of this hormone decline. Estrogen production from androgen precursors is catalyzed by the aromatase enzyme. Although aromatase expression and local estrogen production in breast adipose tissue have been implicated in the development of primary breast cancer, the source of estrogen involved in the regulation of estrogen receptor-positive (ER+) metastatic breast cancer progression is less clear.Bone is the most common distant site of breast cancer metastasis, particularly for ER+ breast cancers. We employed a co-culture model using trabecular  bone tissues obtained from total hip replacement (THR) surgery specimens to study ER+ and estrogen receptor-negative (ER-) breast cancer cells within the human bone microenvironment. Luciferase-expressing ER+ (MCF-7, T-47D, ZR-75) and ER- (SK-BR-3, MDA-MB-231, MCF-10A) breast cancer cells were cultured directly on bone tissue fragments or in bone tissue-conditioned media, and monitored over time with bioluminescence imaging (BLI). Bone tissue-conditioned media were generated in the presence vs. absence of aromatase inhibitors, and testosterone. Bone tissue fragments were analyzed for aromatase expression by immunohistochemistry.ER+ breast cancer cells were preferentially sustained in co-cultures with bone tissues and bone tissue-conditioned media relative to ER- cells. Bone fragments analyzed by immunohistochemistry revealed expression of the aromatase enzyme. Bone tissue-conditioned media generated in the presence of testosterone had increased estrogen levels and heightened capacity to stimulate ER+ breast cancer cell proliferation. Pretreatment of cultured bone tissues with aromatase inhibitors, which inhibited estrogen production, reduced the capacity of conditioned media to stimulate ER+ cell proliferation.These results suggest that a local estrogen signaling axis regulates ER+ breast cancer cell viability and proliferation within the bone metastatic niche, and that aromatase inhibitors modulate this axis. Although endocrine therapies are highly effective in the treatment of ER+ breast cancer, resistance to these treatments reduces their efficacy. Characterization of estrogen signaling networks within the bone microenvironment will identify new strategies for combating metastatic progression and endocrine resistance.

  View details for DOI 10.1186/s13058-017-0910-x

  View details for PubMedID 29141657

  View details for PubMedCentralID PMC5688761

• Headless Compression Screw Fixation of Vertical Medial Malleolus Fractures is Superior to Unicortical Screw Fixation American Journal of Orthopedics Wegner, A. M., Robbins, M. A., Garcia, T. C., Wolinsky, P. R., Amanatullah, D. F. 2017; accepted
• Modularity in Total Hip Arthroplasty: Benefits, Risks, Mechanisms, Diagnosis, and Management. Orthopedics Vierra, B. M., Blumenthal, S. R., Amanatullah, D. F. 2017: 1–12

  Abstract

  Modular implants are currently widely used in total hip arthroplasty because they give surgeons versatility during the operation, allow for easier revision surgery, and can be adjusted to better fit the anatomy of the specific patient. However, modular implants, specifically those that have metal-on-metal junctions, are susceptible to crevice and fretting corrosion. This can ultimately cause implant failure, inflammation, and adverse local tissue reaction, among other possible side effects. Surgeons should be aware of the possibility of implant corrosion and should follow a set of recommended guidelines to systematically diagnose and treat patients with corroded implants. Ultimately, surgeons will continue to use modular implants because of their widespread benefits. However, more research is needed to determine how to minimize corrosion and the negative side effects that have been associated with modular junctions in total hip arthroplasty. [Orthopedics. 201x; xx(x):xx-xx.].

  View details for DOI 10.3928/01477447-20170606-01

  View details for PubMedID 28598491

• Use of Cortical Strut Allograft after Extended Trochanteric Osteotomy in Revision Total Hip Arthroplasty Journal of Arthroplasty, Lim, C. T., Amanatullah, D. F., Huddleston III, J. I., Hwang, K. L., Maloney, W. J., Goodman, S. B. 2017 ; 32(5): 1599-1605.
• Taper Corrosion after Total Hip Arthroplasty: Evaluation and Management Advanced Reconstruction of the Hip, 2nd Edition. Amanatullah, D. F., Taunton, M. J. edited by Lieberman, J. A., Berry, D. J. American Academy of Orthopaedic Surgeons, Rosemont, IL. Chapter 45. 2017: 437–448
• Smoking is associated with earlier time to revision of total knee arthroplasty. The Knee Lim, C. T., Goodman, S. B., Huddleston, J. I., Harris, A. H., Bhowmick, S., Maloney, W. J., Amanatullah, D. F. 2017

  Abstract

  Smoking is associated with early postoperative complications, increased length of hospital stay, and an increased risk of revision after total knee arthroplasty (TKA). However, the effect of smoking on time to revision TKA is unknown.A total of 619 primary TKAs referred to an academic tertiary center for revision TKA were retrospectively stratified according to the patient smoking status. Smoking status was then analyzed for associations with time to revision TKA using a Chi square test. The association was also analyzed according to the indication for revision TKA.Smokers (37/41, 90%) have an increased risk of earlier revision for any reason compared to non-smokers (274/357, 77%, p=0.031). Smokers (37/41, 90%) have an increased risk of earlier revision for any reason compared to ex-smokers (168/221, 76%, p=0.028). Subgroup analysis did not reveal a difference in indication for revision TKA (p>0.05).Smokers are at increased risk of earlier revision TKA when compared to non-smokers and ex-smokers. The risk for ex-smokers was similar to that of non-smokers. Smoking appears to have an all-or-none effect on earlier revision TKA as patients who smoked more did not have higher risk of early revision TKA. These results highlight the need for clinicians to urge patients not to begin smoking and encourage smokers to quit smoking prior to primary TKA.

  View details for DOI 10.1016/j.knee.2017.05.014

  View details for PubMedID 28797880

• Femoral Nerve Catheters Improve Home Disposition and Pain in Hip Fracture Patients Treated With Total Hip Arthroplasty. The Journal of arthroplasty Arsoy, D., Huddleston, J. I., Amanatullah, D. F., Giori, N. J., Maloney, W. J., Goodman, S. B. 2017

  Abstract

  Opioids have been the mainstay of treatment in the physiologically young geriatric hip fracture patient undergoing total hip arthroplasty (THA). However opioid-related side effects increase morbidity. Regional anesthesia may provide better analgesia, while decreasing opioid-related side effects. The goal of this study was to examine the effect of perioperative continuous femoral nerve blockade with regards to pain scores, opioid-related side effects and posthospital disposition in hip fracture patients undergoing THA.Twenty-nine consecutive geriatric hip fracture patients (22 women/7 men) underwent THA. Average follow-up was 8.3 months (6 weeks-39 months). Fifteen patients were treated with standard analgesia (SA). Fourteen patients received an ultrasound-guided insertion of a femoral nerve catheter after radiographic confirmation of a hip fracture. All complications and readmissions that occurred within 6 weeks of surgery were noted.Continuous femoral nerve catheter (CFNC) patients were discharged home more frequently than SA patients (43% for CFNC vs 7% for SA; P = .023). CFNC patients reported lower average pain scores preoperatively (P < .0001), on postoperative day 1 (P = .005) and postoperative day 2 (P = .037). Preoperatively, CFNC patients required 61% less morphine equivalent (P = .007). CFNC patients had a lower rate of opioid-related side effects compared with SA patients (7% vs 47%; P = .035).CFNC patients were discharged to home more frequently. Use of a CFNC decreased daily average patient-reported pain scores, preoperative opioid usage, and opioid-related side effects after THA for hip fracture. Based on these data, we recommend routine use of perioperative CFNC in hip fracture patients undergoing THA.

  View details for DOI 10.1016/j.arth.2017.05.047

  View details for PubMedID 28641968

• Intraobserver Reliability and Interobserver Agreement in Radiographic Classification of Heterotopic Ossification. Orthopedics Vasileiadis, G. I., Itoigawa, Y., Amanatullah, D. F., Pulido-Sierra, L., Crenshaw, J. R., Huyber, C., Taunton, M. J., Kaufman, K. R. 2017; 40 (1): e54-e58

  Abstract

  The most widely used radiologic classification system for heterotopic ossification after total hip arthroplasty (THA) is the Brooker scale. In 2002, Della Valle et al proposed a modified rating system for heterotopic ossification to increase intraobserver reliability and interobserver agreement. To date, no study comparing these 2 classification systems has been conducted. Moreover, these studies were grossly underpowered. In the current study, 3 clinicians reviewed the charts of 236 patients with documented radiographic heterotopic ossification at least 2 months after THA and independently graded the amount of heterotopic ossification according to the Brooker and Della Valle classification systems. Then the intraobserver reliability and the interobserver agreement of each classification system were calculated with Cohen's kappa (κ) coefficient of agreement. The Brooker scale showed moderate to substantial intraobserver reliability (0.43≤κ<0.71), and the Della Valle classification system showed substantial intraobserver reliability (0.65≤κ<0.77). Both classification systems showed moderate interobserver agreement (0.40≤κ<0.60). Della Valle grade C (ie, presence of bone spurs from the pelvis or femur leaving less than 1 cm between opposing surfaces and apparent bone ankylosis) and Brooker grade IV had the best interobserver agreement. The best interobserver agreement for any grade was seen with grade C of the Della Valle classification system, which showed substantial interobserver reliability (0.60≤κ<0.80). The Della Valle classification system may be slightly better in patients with large amounts of heterotopic ossification, but both classification systems lack sufficient clarity and are open to significant subjective interpretation. [Orthopedics. 2017; 40(1):e54-e58.].

  View details for DOI 10.3928/01477447-20160926-05

  View details for PubMedID 27684082

• Cortical Strut Allograft Support of Modular Femoral Junctions during Revision Total Hip Arthroplasty. Journal of Arthroplasty Journal of Arthroplasty Lim, C. T., Amanatullah, D. F., Huddleston III, J. I., Hwang, K. L., Maloney, W. J., Goodman, S. B. 2017; 32(5): 1586-1592.
• Perioperative Physiotherapy in Total Knee Arthroplasty. Amanatullah, D. F., Joice, M. G., Bhowmick, S. Orthopedics, 20: 1-9.. 2017
• Reconstruction of Disrupted Extensor Mechanism After Total Knee Arthroplasty. The Journal of arthroplasty Lim, C. T., Amanatullah, D. F., Huddleston, J. I., Harris, A. H., Hwang, K. L., Maloney, W. J., Goodman, S. B. 2017

  Abstract

  Disruption of the extensor mechanism after total knee arthroplasty (TKA) is a debilitating complication that results in extension lag, limited range of motion, difficulty in walking, frequent falls, and chronic pain. This study presents the clinical and radiographic results of reconstruction after extensor mechanism disruption in TKA patients.Consecutive patients with allograft reconstruction of extensor mechanism after TKA were identified retrospectively from an academic tertiary center for revision TKA.Sixteen patients with a mean age of 61 ± 14 years at extensor mechanism reconstruction with a minimum of 2-year follow-up were included. The mean follow-up was 3.3 ± 2.2 years. Knee Society score (KSS), before and at final follow-up extension lag, range of motion, and radiographic change in patellar height were reviewed. There were statistically significant improvements between preoperative and final follow-up KSS (P < .001; KSS for pain, preoperative 40 ± 14 points to final follow-up 67 ± 15 points [P < .001]; KSS for function, preoperative 26 ± 21 points to final follow-up 48 ± 25 points [P < .001]). The extension lag was also reduced from 35° ± 16° preoperatively to 14° ± 18° (P < .001) at final follow-up. There was an average proximal patellar migration of 8 ± 10 mm. Five (31%) cases had an extensor lag of >30° or revision surgery for repeat extensor mechanism reconstruction, infection, or arthrodesis.Our 10-year experience using allografts during extensor mechanism reconstruction demonstrates reasonable outcomes, but failures are to be anticipated in approximately one-third of patients.

  View details for DOI 10.1016/j.arth.2017.05.005

  View details for PubMedID 28634096

• Intraobserver Reliability and Interobserver Agreement in Radiographic Classification of Heterotopic Ossification ORTHOPEDICS Vasileiadis, G. I., Itoigawa, Y., Amanatullah, D. F., Pulido-Sierra, L., Crenshaw, J. R., Huyber, C., Taunton, M. J., Kaufman, K. R. 2017; 40 (1): E54-E58

  View details for DOI 10.3928/01477447-20160926-05

  View details for Web of Science ID 000397082400008

• Cortical Strut Allograft Support of Modular Femoral Junctions During Revision Total Hip Arthroplasty. journal of arthroplasty Lim, C. T., Amanatullah, D. F., Huddleston, J. I., Hwang, K. L., Maloney, W. J., Goodman, S. B. 2016

  Abstract

  There is risk of junction failure when using modular femoral stems for revision total hip arthroplasty (THA), especially with loss of bone stock in the proximal femur. Using a cortical strut allograft may provide additional support of a modular femoral construct in revision THA.We reviewed prospectively gathered clinical and radiographic data for 28 revision THAs performed from 2004 to 2014 using cementless modular femoral components with cortical strut allograft applied to supplement proximal femoral bone loss: 5 (18%) were fluted taper designs and 23 (82%) were porous cylindrical designs All the patients had a Paprosky grade IIIA or greater femoral defect. The mean follow-up was 5.4 ± 3.9 years.The Harris Hip Scores improved from 26 ± 10 points preoperatively to 71 ± 10 points at final follow-up (P < .001). The Western Ontario McMaster Universities Osteoarthritis Index scores improved from 45 ± 12 points preoperatively to 76 ± 12 points at final follow-up (P < .001). Eighty-nine percent (25 hips) of all revision or conversion THAs were in place at final follow-up. Three (11%) patients underwent reoperations, 2 for infection and 1 for periprosthetic fracture. There was no statistical significant change in femoral component alignment (P = .161) at final follow-up. Mean subsidence was 1.8 ± 1.3 mm at final follow-up. Femoral diameter increased from initial postoperative imaging to final follow-up imaging by a mean of 9.1 ± 5.1 mm (P < .001) and cortical width increased by a mean of 4.5 ± 2.2 mm (P < .001). Twenty-seven hips (96%) achieved union between the cortical strut allograft and the host femur.The use of a modular femoral stem in a compromised femur with a supplementary cortical strut allgraft is safe and provides satisfactory clinical and radiological outcomes.

  View details for DOI 10.1016/j.arth.2016.12.011

  View details for PubMedID 28130016

• Use of Cortical Strut Allograft After Extended Trochanteric Osteotomy in Revision Total Hip Arthroplasty. journal of arthroplasty Lim, C. T., Amanatullah, D. F., Huddleston, J. I., Hwang, K. L., Maloney, W. J., Goodman, S. B. 2016

  Abstract

  Cortical strut allografts restore bone stock and improve postoperative clinical scores after revision total hip arthroplasty (THA). However, use of a cortical strut allograft is implicated in delayed healing of an extended trochanteric osteotomy (ETO). To date, there are no reports directly comparing ETO with or without cortical strut allografts.We reviewed prospectively gathered data on 50 revision THAs performed from 2004-2014 using an ETO. We compared the demographic, radiological, and clinical outcome of patients with (16 hips) and without (34 hips) cortical strut allograft after an ETO.There were no significant differences in Western Ontario McMaster Universities Osteoarthritis Index or Harris Hip Score between the ETOs with and without a cortical strut allograft. Fifteen of the ETOs (94%) with a cortical strut allograft and 31 of the ETOs (91%) without a cortical strut allograft were in situ at final follow-up (P = 1.000). A higher proportion hips with cortical strut allograft (100%, 16 patients) had preoperative Paprosky grade bone loss more than IIIA compared to those without allograft (29%, 10 patients) (P < .001). There were no differences in femoral stem subsidence (P = .207), alignment (P = .934), or migration of the osteotomized fragment (P = .171). Fourteen of the ETOs (88%) in patients with cortical strut allograft united compared to 34 ETOs (100%) in patients without allograft (P = .095).Our study shows that the use of cortical strut allograft during revision THA with ETO does not reduce the rate of union, radiological or clinical outcomes.

  View details for DOI 10.1016/j.arth.2016.12.002

  View details for PubMedID 28110850

• Proximal femoral reconstruction for failed internal fixation of a bisphosphonate-related femur fracture. Arthroplasty today Jethanandani, R. G., Nwankwo, C., Wolinsky, P. R., Giordani, M., Amanatullah, D. F. 2016; 2 (4): 153-156

  Abstract

  We present a case of a bisphosphonate-related femur fracture in an elderly woman, who failed treatment with both cephalomedullary nail and proximal femoral locking plate, leading to successful treatment with total hip arthroplasty. Hardware failure should be included in the differential of patients with previous internal fixation of bisphosphonate-related femur fracture that present with hip or groin pain. Arthroplasty can be an acceptable salvage option in an active elderly patient with a bisphosphonate-related femur fracture.

  View details for DOI 10.1016/j.artd.2016.04.001

  View details for PubMedID 28326420

• Metal in Total Hip Arthroplasty: Wear Particles, Biology, and Diagnosis ORTHOPEDICS Amanatullah, D. F., Sucher, M. G., Bonadurer, G. F., Pereira, G. C., Taunton, M. J. 2016; 39 (6): 371-379

  Abstract

  Total hip arthroplasty (THA) has been performed for nearly 50 years. Between 2006 and 2012, more than 600,000 metal-on-metal THA procedures were performed in the United States. This article reviews the production of metal wear debris in a metal-on-metal articulation and the interaction of cobalt and chromium ions that ultimately led to a dramatic decline in the use of metal-on-metal THA articulations. Additionally, the article reviews mechanisms of metal wear, the biologic reaction to cobalt and chromium ions, the clinical presentation of failing metal-on-metal articulations, and current diagnostic strategies. Further, the article discusses the use of inflammatory markers, metal ion levels, radiographs, metal artifact reduction sequence magnetic resonance imaging, and ultrasound for failed metal-on-metal THA procedures. When adopting new technologies, orthopedic surgeons must weigh the potential increased benefits against the possibility of new mechanisms of failure. Metal-on-metal bearings are a prime example of the give and take between innovation and clinical results, especially in the setting of an already successful procedure such as THA. [Orthopedics. 2016; 39(6):371-379.].

  View details for DOI 10.3928/01477447-20160719-06

  View details for Web of Science ID 000393108800042

  View details for PubMedID 27459144

• Calculating the Position of the Joint Line of the Knee Using Anatomical Landmarks. Orthopedics Pereira, G. C., Von Kaeppler, E., Alaia, M. J., Montini, K., Lopez, M. J., Di Cesare, P. E., Amanatullah, D. F. 2016; 39 (6): 381-386

  Abstract

  Restoration of the joint line of the knee during primary and revision total knee arthroplasty is a step that directly influences patient outcomes. In revision total knee arthroplasty, necessary bony landmarks may be missing or obscured, so there remains a lack of consensus on how to accurately identify and restore the joint line of the knee. In this study, 50 magnetic resonance images of normal knees were analyzed to determine a quantitative relationship between the joint line of the knee and 6 bony landmarks: medial and lateral femoral epicondyles, medial and lateral femoral metaphyseal flares, tibial tubercle, and proximal tibio-fibular joint. Wide variability was found in the absolute distance from each landmark to the joint line of the knee, including significant differences between the sexes. Normalization of the absolute distances to femoral or tibial diameters revealed reliable spatial relationships to the joint line of the knee. The joint line was found to be equidistant from the lateral femoral epicondyle and the proximal tibio-fibular joint, representing a reproducible point of reference for joint line restoration. The authors propose a simple 3-step algorithm that can be used with magnetic resonance imaging, computed tomography, or radiography to reliably determine the anatomical location of the joint line of the knee relative to the surrounding bony anatomy. [Orthopedics. 2016; 39(6):381-386.].

  View details for DOI 10.3928/01477447-20160729-01

  View details for PubMedID 27482732

• Calculating the Position of the Joint Line of the Knee Using Anatomical Landmarks ORTHOPEDICS Pereira, G. C., Von Kaeppler, E., Alaia, M. J., Montini, K., Lopopez, M. J., Di Cesare, P. E., Amanatullah, D. F. 2016; 39 (6): 381-386

  View details for DOI 10.3928/01477447-20160729-01

  View details for Web of Science ID 000393108800043

• Tibiofemoral Dislocation After Total Knee Arthroplasty. journal of arthroplasty Jethanandani, R. G., Maloney, W. J., Huddleston, J. I., Goodman, S. B., Amanatullah, D. F. 2016; 31 (10): 2282-2285

  Abstract

  Tibiofemoral dislocation after total knee arthroplasty (TKA) is a rare complication. Published case reports describe fewer than 6 patients, making conclusions about the etiology, epidemiology, complications, and treatment of tibiofemoral dislocation difficult. This case series highlights common demographic features, potential causes, and difficulties during the management of tibiofemoral dislocations after TKA.Between 2005 and 2014, 14 patients presented to our institution with a tibiofemoral dislocation. Patients were excluded if they had patellofemoral dislocation or subluxation without a tibiofemoral dislocation. We retrospectively reviewed patient demographics, time to first dislocation, number of dislocations, time to surgical intervention, complications, and potential etiologies of tibiofemoral dislocation.Twelve of 14 patients were female. Their mean body mass index was 33 ± 10 kg/m(2). Thirteen of 14 patients had a mean of 2.0 ± 1.4 dislocations. Four patients dislocated due to polyethylene damage and 5 due to ligamentous incompetence. Twelve of 14 patients required open surgical intervention. Complications in this patient population were common with 3 cases of infection, 7 cases of multiple dislocation, 2 cases of popliteal artery laceration, 1 case receiving a fusion, and 1 case receiving an amputation.Patients with tibiofemoral dislocation after TKA are predominantly obese, female, and have a high risk for complications. They dislocate predominantly because of polyethylene damage or ligamentous incompetence. Re-dislocation is common if treated with closed reduction alone.

  View details for DOI 10.1016/j.arth.2016.03.010

  View details for PubMedID 27084503

• Obesity is Associated With Early Total Hip Revision for Aseptic Loosening. journal of arthroplasty Electricwala, A. J., Narkbunnam, R., Huddleston, J. I., Maloney, W. J., Goodman, S. B., Amanatullah, D. F. 2016; 31 (9): 217-220

  Abstract

  Obesity affects more than half a billion people worldwide, including one-third of men and women in the United States. Obesity is associated with higher postoperative complication rates after total hip arthroplasty (THA). It remains unknown whether obese patients progress to revision THA faster than nonobese patients.A total of 257 consecutive primary THAs referred to an academic tertiary care center for revision THA were retrospectively stratified according to preoperative body mass index (BMI), reason for revision THA, and time from primary to revision THA.When examining primary THAs referred for revision THA, increasing BMI adversely affected the mean time to revision THA. The percentage of primary THAs revised at 5 years was 25% for a BMI of 18-25, 38% for a BMI of 25-30, 56% for a BMI of 30-35, 73% for a BMI of 35-40, and 75% for a BMI of greater than 40 (P < .001). The percentage of primary THAs revised at 15 years was 70%, 82%, 87%, 94%, and 100%, respectively (P < .001). A significant increase in early revision THA for aseptic loosening/osteolysis in obese patients (56%, 23/41) when compared with the nonobese patients (12%, 10/83, P < .001, relative risk ratio = 4.7).Preoperative BMI influences the time of failure of primary THAs referred to an academic tertiary care for revision THA as well as the mechanism of failure. Specifically, obesity increased in the relative risk of early revision THA due to aseptic loosening/osteolysis by 4.7 fold.

  View details for DOI 10.1016/j.arth.2016.02.073

  View details for PubMedID 27108056

• Obesity is Associated With Early Total Hip Revision for Aseptic Loosening JOURNAL OF ARTHROPLASTY Electricwala, A. J., Narkbunnam, R., Huddleston, J. I., Maloney, W. J., Goodman, S. B., Amanatullah, D. F. 2016; 31 (9): S217-S220

  Abstract

  Obesity affects more than half a billion people worldwide, including one-third of men and women in the United States. Obesity is associated with higher postoperative complication rates after total hip arthroplasty (THA). It remains unknown whether obese patients progress to revision THA faster than nonobese patients.A total of 257 consecutive primary THAs referred to an academic tertiary care center for revision THA were retrospectively stratified according to preoperative body mass index (BMI), reason for revision THA, and time from primary to revision THA.When examining primary THAs referred for revision THA, increasing BMI adversely affected the mean time to revision THA. The percentage of primary THAs revised at 5 years was 25% for a BMI of 18-25, 38% for a BMI of 25-30, 56% for a BMI of 30-35, 73% for a BMI of 35-40, and 75% for a BMI of greater than 40 (P < .001). The percentage of primary THAs revised at 15 years was 70%, 82%, 87%, 94%, and 100%, respectively (P < .001). A significant increase in early revision THA for aseptic loosening/osteolysis in obese patients (56%, 23/41) when compared with the nonobese patients (12%, 10/83, P < .001, relative risk ratio = 4.7).Preoperative BMI influences the time of failure of primary THAs referred to an academic tertiary care for revision THA as well as the mechanism of failure. Specifically, obesity increased in the relative risk of early revision THA due to aseptic loosening/osteolysis by 4.7 fold.

  View details for DOI 10.1016/j.arth.2016.02.073

  View details for Web of Science ID 000382208900046

• Greater inadvertent muscle damage in direct anterior approach when compared with the direct superior approach for total hip arthroplasty. The bone & joint journal Amanatullah, D. F., Masini, M. A., ROGER, D. J., Pagnano, M. W. 2016; 98-B (8): 1036-1042

  Abstract

  We wished to quantify the extent of soft-tissue damage sustained during minimally invasive total hip arthroplasty through the direct anterior (DA) and direct superior (DS) approaches.In eight cadavers, the DA approach was performed on one side, and the DS approach on the other, a single brand of uncemented hip prosthesis was implanted by two surgeons, considered expert in their surgical approaches. Subsequent reflection of the gluteus maximus allowed the extent of muscle and tendon damage to be measured and the percentage damage to each anatomical structure to be calculated.The DA approach caused substantially greater damage to the gluteus minimus muscle and tendon when compared with the DS approach (t-test, p = 0.049 and 0.003, respectively). The tensor fascia lata and rectus femoris muscles were damaged only in the DA approach. There was no difference in the amount of damage to the gluteus medius muscle and tendon, piriformis tendon, obturator internus tendon, obturator externus tendon or quadratus femoris muscle between approaches. The posterior soft-tissue releases of the DA approach damaged the gluteus minimus muscle and tendon, piriformis tendon and obturator internus tendon.The DS approach caused less soft-tissue damage than the DA approach. However the clinical relevance is unknown. Further clinical outcome studies, radiographic evaluation of component position, gait analyses and serum biomarker levels are necessary to evaluate and corroborate the safety and efficacy of the DS approach. Cite this article: Bone Joint J 2016;98-B1036-42.

  View details for DOI 10.1302/0301-620X.98B8.37178

  View details for PubMedID 27482014

• Greater inadvertent muscle damage in direct anterior approach when compared with the direct superior approach for total hip arthroplasty BONE & JOINT JOURNAL Amanatullah, D. F., Masini, M. A., ROGER, D. J., Pagnano, M. W. 2016; 98B (8): 1036-1042

  View details for DOI 10.1302/0301-620X.98B8.37178

  View details for Web of Science ID 000380953100006

• Biomechanical Consequences of Anterior Femoral Notching in Cruciate-Retaining Versus Posterior-Stabilized Total Knee Arthroplasty. American journal of orthopedics (Belle Mead, N.J.) Jethanandani, R., Patwary, M. B., Shellito, A. D., Meehan, J. P., Amanatullah, D. F. 2016; 45 (5): E268-72

  Abstract

  Anterior femoral notching during total knee arthroplasty is a potential risk factor for periprosthetic supracondylar femur fracture. We conducted a study to determine if the design of the femoral implant changes the risk for periprosthetic supracondylar femur fractures after anterior cortical notching. An anterior cortical defect was created in 12 femoral polyurethane models. Six femora were instrumented with cruciate-retaining implants and 6 with posterior-stabilized implants. Each femur was loaded in external rotation along the anatomical axis. Notch depth and distance from anterior cortical notch to implant were recorded before loading, and fracture pattern was recorded after failure. There were no statistically significant differences in notch depth, distance from notch to implant, torsional stiffness, torque at failure, final torque, or fracture pattern between cruciate-retaining and posterior-stabilized femoral component designs. Periprosthetic fracture after anterior femoral notching is independent of the bone removed from the intercondylar notch. After notching, there likely is no significant difference in femoral strength in torsion between cruciate-retaining and posterior-stabilized designs.

  View details for PubMedID 27552464

• The biological response to orthopaedic implants for joint replacement: Part I: Metals. Journal of biomedical materials research. Part B, Applied biomaterials Gibon, E., Amanatullah, D. F., Loi, F., Pajarinen, J., Nabeshima, A., Yao, Z., Hamadouche, M., Goodman, S. B. 2016

  Abstract

  Joint replacement is a commonly performed, highly successful orthopaedic procedure, for which surgeons have a large choice of different materials and implant designs. The materials used for joint replacement must be both biologically acceptable to minimize adverse local tissue reactions, and robust enough to support weight bearing during common activities of daily living. Modern joint replacements are made from metals and their alloys, polymers, ceramics, and composites. This review focuses on the biological response to the different biomaterials used for joint replacement. In general, modern materials for joint replacement are well tolerated by the body as long as they are in bulk (rather than in particulate or ionic) form, are mechanically stable and noninfected. If the latter conditions are not met, the prosthesis will be associated with an acute/chronic inflammatory reaction, peri-prosthetic osteolysis, loosening and failure. This article (Part 1 of 2) is dedicated to the use of metallic devices in orthopaedic surgery including the associated biological response to metallic byproducts is a review of the basic science literature regarding this topic. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.

  View details for DOI 10.1002/jbm.b.33734

  View details for PubMedID 27328111

• Phlpp1 facilitates post-traumatic osteoarthritis and is induced by inflammation and promoter demethylation in human osteoarthritis OSTEOARTHRITIS AND CARTILAGE Bradley, E. W., Carpio, L. R., McGee-Lawrence, M. E., Becerra, C. C., Amanatullah, D. F., Ta, L. E., OTERO, M., GOLDRING, M. B., Kakar, S., Westendorf, J. J. 2016; 24 (6): 1021-1028

  Abstract

  Osteoarthritis (OA) is the most common form of arthritis and a leading cause of disability. OA is characterized by articular chondrocyte deterioration, subchondral bone changes and debilitating pain. One strategy to promote cartilage regeneration and repair is to accelerate proliferation and matrix production of articular chondrocytes. We previously reported that the protein phosphatase Phlpp1 controls chondrocyte differentiation by regulating the activities of anabolic kinases. Here we examined the role of Phlpp1 in OA progression in a murine model. We also assessed PHLPP1 expression and promoter methylation.Knee joints of WT and Phlpp1(-/-) mice were surgically destabilized by transection of the medial meniscal ligament (DMM). Mice were assessed for signs of OA progression via radiographic and histological analyses, and pain assessment for mechanical hypersensitivity using the von Frey assay. Methylation of the PHLPP1 promoter and PHLPP1 expression were evaluated in human articular cartilage and chondrocyte cell lines.Following DMM surgeries, Phlpp1 deficient mice showed fewer signs of OA and cartilage degeneration. Mechanical allodynia associated with DMM surgeries was also attenuated in Phlpp1(-/-) mice. PHLPP1 was highly expressed in human articular cartilage from OA patients, but was undetectable in cartilage specimens from femoral neck fractures (FNFxs). Higher PHLPP1 levels correlated with less PHLPP1 promoter CpG methylation in cartilage from OA patients. Blocking cytosine methylation or treatment with inflammatory mediators enhanced PHLPP1 expression in human chondrocyte cell lines.Phlpp1 deficiency protects against OA progression while CpG demethylation and inflammatory cytokines promote PHLPP1 expression.

  View details for DOI 10.1016/j.joca.2015.12.014

  View details for Web of Science ID 000376040400010

  View details for PubMedID 26746148

  View details for PubMedCentralID PMC4875839

• Antiglide plating of vertical medial malleolus fractures provides stiffer initial fixation than bicortical or unicortical screw fixation. Clinical biomechanics Wegner, A. M., Wolinsky, P. R., Robbins, M. A., Garcia, T. C., Maitra, S., Amanatullah, D. F. 2016; 31: 29-32

  Abstract

  Vertical shear fractures of the medial malleolus (44-A2 ankle fractures) occur through a supination-adduction mechanism. There are numerous methods of internal fixation for this fracture pattern.Vertical medial malleolus osteotomies were created in synthetic distal tibiae. The models were divided into four fixation groups: two parallel unicortical cancellous screws, two divergent unicortical cancellous screws, two parallel bicortical cortical screws, or an antiglide plate construct. Specimens were subjected to offset axial loading and tracked using high-resolution video.The antiglide plate construct was stiffer (P<0.05) than each of the other three constructs, and the bicortical screw construct was stiffer (P<0.05) than both unicortical screw constructs. The mean stiffness (standard deviation) was 111 (SD 35) N/mm for the parallel unicortical screw construct, 173 (SD 57) N/mm for the divergent unicortical screw construct, 279 (SD 30) N/mm for the bicortical screw construct, and 463 (SD 91) N/mm for the antiglide plate construct. The antiglide plate construct resisted displacement better (P<0.05) than each of the other three constructs. The mean force for 2mm of articular displacement was 284 (SD 51) N for the parallel unicortical screw construct, 339 (SD 46) N for the divergent unicortical screw construct, 429 (SD 112) N for the bicortical construct, and 922 (SD 297) N for the antiglide plate construct.An antiglide plate construct provides the stiffest initial fixation while withstanding higher load to failure for vertical medial malleolus fractures when compared to unicortical and bicortical screw fixation.

  View details for DOI 10.1016/j.clinbiomech.2015.10.005

  View details for PubMedID 26482240

• Minimally Invasive Total Hip Arthroplasty Medscape Drugs and Disease, http://emedicine.medscape.com/article/2000333-overview Amanatullah, D. F., Joice, M., Di Cesare, P. E. 2016
• Techniques to Manage Osteolysis around Well-fixed Acetabular Components Master Techniques in Orthopaedic Surgery: The Hip, 3rd Edition. Amanatullah, D. F., Maloney, W. J. edited by Berry, D. J., Maloney, W. J. Chapter 31. 2016: 411–419
• Taking the Big Bite: Rothman-Ranawat Traveling Fellows Chew on Their Lessons AAOS Now Wilson, M., Loganathan, B., Kamath, A., Amanatullah, D. 2016
• Pre-operative Planning The Adult Hip, Hip arthroplasty Surgery, 3rd Edition Pereira, G. C., Amanatullah, D. F., Di Ceasare, P. E. edited by Calaghan, J. J., Rosenberg, A. G., Rubash, H. E., Clohisy, J. C., Beaule, P. E., Della Valle, C. J. 2016 ; Chapter 50: 672–683
• Comprehensive Operative Note Templates for Primary and Revision Total Hip and Knee Arthroplasty. The open orthopaedics journal Electricwala, A. J., Amanatullah, D. F., Narkbunnam, R. I., Huddleston, J. I., Maloney, W. J., Goodman, S. B. 2016; 10: 725-731

  Abstract

  Adequate preoperative planning is the first and most crucial step in the successful completion of a revision total joint arthroplasty. The purpose of this study was to evaluate the availability, adequacy and accuracy of operative notes of primary surgeries in patients requiring subsequent revision and to construct comprehensive templates of minimum necessary information required in the operative notes to further simplify re-operations, if they should become necessary.The operative notes of 144 patients (80 revision THA's and 64 revision TKA's) who underwent revision total joint arthroplasty at Stanford Hospital and Clinics in the year 2013 were reviewed. We assessed the availability of operative notes and implant stickers prior to revision total joint arthroplasty. The availability of implant details within the operative notes was assessed against the available surgical stickers for adequacy and accuracy. Statistical comparisons were made using the Fischer-exact test and a P-value of less than 0.05 was considered statistically significant.The primary operative note was available in 68 of 144 revisions (47%), 39 of 80 revision THAs (49%) and 29 of 66 revision TKAs (44%, p = 0.619). Primary implant stickers were available in 46 of 144 revisions (32%), 26 of 80 revision THAs (32%) and 20 of 66 revision TKAs (30%, p = 0.859). Utilizing the operative notes and implant stickers combined identified accurate primary implant details in only 40 of the 80 revision THAs (50%) and 34 of all 66 revision TKAs (52%, p = 0.870).Operative notes are often unavailable or fail to provide the necessary information required which makes planning and execution of revision hip and knee athroplasty difficult. This emphasizes the need for enhancing the quality of operative notes and records of patient information. Based on this information, we provide comprehensive operative note templates for primary and revision total hip and knee arthroplasty.

  View details for DOI 10.2174/1874325001610010725

  View details for PubMedID 28144382

  View details for PubMedCentralID PMC5220177

• Revision total hip arthroplasty after removal of a fractured well-fixed extensively porous-coated femoral component using a trephine. The bone & joint journal Amanatullah, D. F., Siman, H., Pallante, G. D., Haber, D. B., Sierra, R. J., Trousdale, R. T. 2015; 97-B (9): 1192-1196

  Abstract

  When fracture of an extensively porous-coated femoral component occurs, its removal at revision total hip arthroplasty (THA) may require a femoral osteotomy and the use of a trephine. The remaining cortical bone after using the trephine may develop thermally induced necrosis. A retrospective review identified 11 fractured, well-fixed, uncemented, extensively porous-coated femoral components requiring removal using a trephine with a minimum of two years of follow-up. The mean time to failure was 4.6 years (1.7 to 9.1, standard deviation (sd) 2.3). These were revised using a larger extensively porous coated component, fluted tapered modular component, a proximally coated modular component, or a proximal femoral replacement. The mean clinical follow-up after revision THA was 4.9 years (2 to 22, sd 3.1). The mean diameter of the femoral component increased from 12.7 mm (sd 1.9) to 16.2 mm (sd 3.4; p > 0.001). Two revision components had radiographic evidence of subsidence that remained radiographically stable at final follow-up. The most common post-operative complication was instability affecting six patients (54.5%) on at least one occasion. A total of four patients (36.4%) required further revision: three for instability and one for fracture of the revision component. There was no statistically significant difference in the mean Harris hip score before implant fracture (82.4; sd 18.3) and after trephine removal and revision THA (81.2; sd 14.8, p = 0.918). These findings suggest that removal of a fractured, well-fixed, uncemented, extensively porous-coated femoral component using a trephine does not compromise subsequent fixation at revision THA and the patient's pre-operative level of function can be restored. However, the loss of proximal bone stock before revision may be associated with a high rate of dislocation post-operatively. Cite this article: Bone Joint J 2015;97-B:1192-6.

  View details for DOI 10.1302/0301-620X.97B9.35037

  View details for PubMedID 26330584

• Revision total hip arthroplasty after removal of a fractured well-fixed extensively porous-coated femoral component using a trephine BONE & JOINT JOURNAL Amanatullah, D. F., Siman, H., Pallante, G. D., Haber, D. B., Sierra, R. J., Trousdale, R. T. 2015; 97B (9): 1192-1196

  View details for DOI 10.1302/0301-620X.97B9.35037

  View details for Web of Science ID 000360770000007

• Total Hip Arthroplasty After Lower Extremity Amputation ORTHOPEDICS Amanatullah, D. F., Trousdale, R. T., Sierra, R. J. 2015; 38 (5): E394-E400

  Abstract

  There are approximately 1.6 million lower extremity amputees in the United States. Lower extremity amputees are subject to increased physical demands proportional to their level of amputation. Lower extremity amputees have a 6-fold higher risk of developing radiographic osteoarthritis in the ipsilateral hip and a 2-fold risk of developing radiographic osteoarthritis in contralateral hip when compared with the non-amputee population. Additionally, there is a 3-fold increased risk of developing radiographic osteoarthritis in the ipsilateral hip after an above knee amputation when compared with a below knee amputation. The authors retrospectively reviewed 35 total hip arthroplasties after lower extremity amputation. The mean clinical follow-up was 5.3±4.0 years. The mean time from lower extremity amputation to total hip arthroplasty was 12.2±12.8 years after a contralateral amputation and 5.4±6.0 years after an ipsilateral amputation (P=.050). The mean time to total hip arthroplasty was 15.6±15.4 years after an above knee amputation and 6.4±6.1 years after a below knee amputation (P=.021). There was a statistically significant improvement in the mean Harris Hip Score from 35.9±21.8 to 76.8±12.8 with total hip arthroplasty after a contralateral amputation (P<.001). There also was a statistically significant improvement in the mean Harris Hip Score from 25.4±21.7 to 78.6±17.1 with total hip arthroplasty after an ispilateral amputation (P<.001). Three (17.7%) total hip arthroplasties after a contralateral amputation and 2 (11.1%) total hip arthroplasties after an ipsilateral amputation required revision total hip arthroplasty. Patients with an ipsilateral amputation or a below knee amputation progress to total hip arthroplasty faster than those with a contralateral amputation or an above knee amputation, respectively. Lower extremity amputees experience clinically significant improvements with total hip arthroplasty after lower extremity amputation.

  View details for DOI 10.3928/01477447-20150504-56

  View details for Web of Science ID 000356148900007

  View details for PubMedID 25970366

• Revision total hip arthroplasty in patients with extensive proximal femoral bone loss using a fluted tapered modular femoral component. The bone & joint journal Amanatullah, D. F., Howard, J. L., Siman, H., Trousdale, R. T., Mabry, T. M., Berry, D. J. 2015; 97-B (3): 312-317

  Abstract

  Revision total hip arthroplasty (THA) is challenging when there is severe loss of bone in the proximal femur. The purpose of this study was to evaluate the clinical and radiographic outcomes of revision THA in patients with severe proximal femoral bone loss treated with a fluted, tapered, modular femoral component. Between January 1998 and December 2004, 92 revision THAs were performed in 92 patients using a single fluted, tapered, modular femoral stem design. Pre-operative diagnoses included aseptic loosening, infection and peri-prosthetic fracture. Bone loss was categorised pre-operatively as Paprosky types III-IV, or Vancouver B3 in patients with a peri-prosthetic fracture. The mean clinical follow-up was 6.4 years (2 to 12). A total of 47 patients had peri-operative complications, 27 of whom required further surgery. However, most of these further operations involved retention of a well-fixed femoral stem, and 88/92 femoral components (97%) remained in situ. Of the four components requiring revision, three were revised for infection and were well fixed at the time of revision; only one (1%) was revised for aseptic loosening. The most common complications were post-operative instability (17 hips, 19%) and intra-operative femoral fracture during insertion of the stem (11 hips, 12%). Diaphyseal stress shielding was noted in 20 hips (22%). There were no fractures of the femoral component. At the final follow-up 78% of patients had minimal or no pain. Revision THA in patients with extensive proximal femoral bone loss using the Link MP fluted, tapered, modular stem led to a high rate of osseointegration of the stem at mid-term follow-up. Cite this article: Bone Joint J 2015; 97-B:312-17.

  View details for DOI 10.1302/0301-620X.97B3.34684

  View details for PubMedID 25737513

• Effect of Heterotopic Ossification on Hip Range of Motion and Clinical Outcome JOURNAL OF ARTHROPLASTY Vasileiadis, G. I., Amanatullah, D. F., Crenshaw, J. R., Taunton, M. J., Kaufman, K. R. 2015; 30 (3): 461-464

  Abstract

  The utility of heterotopic ossification (HO) classification systems is debatable. The range of motion and Harris hip score (HHS) were calculated in 104 patients with known HO after total hip arthroplasty and 208 matched controls without HO. The patients with HO were radiographically divided into high and low grade HO groups. There was no statistically significant association of HHS with high or low grade HO. High grade HO had a statistically significant 6° loss of terminal hip flexion, 4° loss of abduction, and 6° loss of internal rotation at the hip. The small changes in terminal hip range of motion and lack of association with HHS may be the result of false radiographic continuity resulting in an overestimation of the disability in high grade HO.

  View details for DOI 10.1016/j.arth.2014.09.019

  View details for Web of Science ID 000353503500028

  View details for PubMedID 25449585

• Femoroacetabular Impingement: Current Concepts in Diagnosis and Treatment ORTHOPEDICS Amanatullah, D. F., Antkowiak, T., Pillay, K., Patel, J., Refaat, M., Toupadakis, C. A., Jamali, A. A. 2015; 38 (3): 185-199

  Abstract

  As a result of reading this article, physicians should be able to: 1. Identify the etiology of femoroacetabular impingement. 2. Assess femoroacetabular impingement on physical examination. 3. Recognize femoroacetabular impingement on imaging studies. 4. Discuss modern techniques to effectively treat femoroacetabular impingement, both open and arthroscopic. Femoroacetabular impingement (FAI) is a recently proposed concept describing abnormal anatomic relationships within the hip joint that may lead to articular damage. Impingement is caused by bony deformities or spatial malorientation of the femoral head-neck junction and/or the acetabulum. These abnormalities lead to pathologic contact and shearing forces at the acetabular labrum and cartilage during physiological hip motion. There is an increasing body of evidence that these forces lead to cartilage wear and eventual osteoarthritis. Treatment options for FAI are evolving rapidly. Although the gold standard remains open hip dislocation, arthroscopic techniques have shown significant promise. It is possible that early recognition and treatment of subtle deformity about the hip may reduce the rate of hip osteoarthritis in the future.

  View details for DOI 10.3928/01477447-20150305-07

  View details for Web of Science ID 000352155600024

  View details for PubMedID 25760499

• Revision total hip arthroplasty in patients with extensive proximal femoral bone loss using a fluted tapered modular femoral component BONE & JOINT JOURNAL Amanatullah, D. F., Howard, J. L., Siman, H., Trousdale, R. T., Mabry, T. M., Berry, D. J. 2015; 97B (3): 312-317

  View details for DOI 10.1302/0301-620X.97B3.34684

  View details for Web of Science ID 000351190500006

• Acetabular Fractures: What Radiologists Should Know and How 3D CT Can Aid Classification RADIOGRAPHICS Scheinfeld, M. H., Dym, A. A., Spektor, M., Avery, L. L., Dym, R. J., Amanatullah, D. F. 2015; 35 (2): 555-577

  Abstract

  Correct recognition, description, and classification of acetabular fractures is essential for efficient patient triage and treatment. Acetabular fractures may result from high-energy trauma or low-energy trauma in the elderly. The most widely used acetabular fracture classification system among radiologists and orthopedic surgeons is the system of Judet and Letournel, which includes five elementary (or elemental) and five associated fractures. The elementary fractures are anterior wall, posterior wall, anterior column, posterior column, and transverse. The associated fractures are all combinations or partial combinations of the elementary fractures and include transverse with posterior wall, T-shaped, associated both column, anterior column or wall with posterior hemitransverse, and posterior column with posterior wall. The most unique fracture is the associated both column fracture, which completely dissociates the acetabular articular surface from the sciatic buttress. Accurate categorization of acetabular fractures is challenging because of the complex three-dimensional (3D) anatomy of the pelvis, the rarity of certain acetabular fracture variants, and confusing nomenclature. Comparing a 3D image of the fractured acetabulum with a standard diagram containing the 10 Judet and Letournel categories of acetabular fracture and using a flowchart algorithm are effective ways of arriving at the correct fracture classification. Online supplemental material is available for this article.

  View details for DOI 10.1148/rg.352140098

  View details for Web of Science ID 000352561000021

  View details for PubMedID 25763739

• Similar Clinical Outcomes for THAs With and Without Prior Periacetabular Osteotomy. Clinical orthopaedics and related research Amanatullah, D. F., Stryker, L., Schoenecker, P., Taunton, M. J., Clohisy, J. C., Trousdale, R. T., Sierra, R. J. 2015; 473 (2): 685-691

  Abstract

  Some patients opt to undergo conversion to a THA for continued pain or progression of hip arthritis after periacetabular osteotomy. Whether patients are at greater risk for postoperative complications, revision THA, poor clinical outcomes, or compromised radiographic results after periacetabular osteotomy is debatable.When compared with a matched cohort of patients who underwent THAs for developmental dysplasia of the hip (DDH) without previous periacetabular osteotomy, we asked whether a THA after a periacetabular osteotomy has (1) a higher complication rate, (2) a higher likelihood of resulting in revision THA, (3) comparable improvements in Harris hip score, and (4) comparable radiographic results.A multicenter retrospective review of 562 patients undergoing 645 periacetabular osteotomies was performed. Twenty-three hips in 22 patients underwent a THA after periacetabular osteotomy. The patients were matched for age, sex, and BMI with 23 hips in 23 patients with DDH undergoing THA without a history of periacetabular osteotomy. Minimum followup for both groups of patients was 2 years (mean, 10 ± 4 years and 6 ± 4 years, respectively). Comparisons were made to answer the study questions based on a retrospective review from prospectively maintained registries of clinical and radiographic information at two participating centers.With the numbers available, there was no difference in complication or revision rates between the two groups (p = 0.489 and 1.000, respectively); however, a post hoc power analysis showed our study was underpowered to detect a difference in the rate of postoperative complications or revision THA. There was marked improvement in Harris hip score with THA after periacetabular osteotomy (p < 0.001) and THA for DDH (p < 0.001), but there was no difference (p = 0.265) in the Harris hip score at final followup between either group. The acetabular component was placed at a mean of 17° more retroversion during THA after periacetabular osteotomy compared with THA for DDH (p = 0.002).This study did not detect any differences in the clinical outcomes in patients undergoing THA after periacetabular osteotomy done with a modern abductor-sparing approach when compared with a matched cohort undergoing THA for DDH. However, even with patients tallied across two high-volume centers during nearly 15 years, our study was underpowered to detect potentially important differences between the THA after periacetabular osteotomy group and the THA for DDH group. The data in this report are suitable as pilot data for future studies and for systematic reviews. Larger multicenter studies are needed to understand how the technical challenges of THA after periacetabular osteotomy affect postoperative complications and revision THA.Level III, therapeutic study.

  View details for DOI 10.1007/s11999-014-4026-7

  View details for PubMedID 25359629

• Polyethylene Liner Exchange and Pelvic Osteolysis. Master Techniques in Orthpaedic Surgery. Amanatullah, D. F., Maloney, W. J. 2015
• Minimally Invasive Total Knee Arthroplasty Medscape http://emedicine.medscape.com/article/2000356-overview. Amanatullah, D. F., Di Cesare, P. E. 2015
• Osteonecrosis. Chapman's Comprehensive Orthopaedic Surgery. Arsoy, D., Amanatullah, D. F. 2015
• Total hip replacement in patients with Down syndrome and degenerative osteoarthritis of the hip. The bone & joint journal Amanatullah, D. F., Rachala, S. R., Trousdale, R. T., Sierra, R. J. 2014; 96-B (11): 1455-1458

  Abstract

  Dysplasia of the hip, hypotonia, osteopenia, ligamentous laxity, and mental retardation increase the complexity of performing and managing patients with Down syndrome who require total hip replacement (THR). We identified 14 patients (six males, eight females, 21 hips) with Down syndrome and degenerative disease of the hip who underwent THR, with a minimum follow-up of two years from 1969 to 2009. In seven patients, bilateral THRs were performed while the rest had unilateral THRs. The mean clinical follow-up was 5.8 years (standard deviation (sd) 4.7; 2 to 17). The mean Harris hip score was 37.9 points (sd 7.8) pre-operatively and increased to 89.2 (sd 12.3) at final follow-up (p = 1x10(-9)). No patient suffered a post-operative dislocation. In three patients, four hips had revision THR for aseptic loosening at a mean follow-up of 7.7 years (sd 6.3; 3 to 17). This rate of revision THR was higher than expected. Our patients with Down syndrome benefitted clinically from THR at mid-term follow-up.

  View details for DOI 10.1302/0301-620X.96B11.34089

  View details for PubMedID 25371456

• Total hip replacement in patients with Down syndrome and degenerative osteoarthritis of the hip BONE & JOINT JOURNAL Amanatullah, D. F., Rachala, S. R., Trousdale, R. T., Sierra, R. J. 2014; 96B (11): 1455-1458

  View details for DOI 10.1302/0301-620X.96B11.34089

  View details for Web of Science ID 000345026600006

• Non-Oncologic Total Femoral Arthroplasty: Retrospective Review JOURNAL OF ARTHROPLASTY Amanatullah, D. F., Trousdale, R. T., Hanssen, A. D., Lewallen, D. G., Taunton, M. J. 2014; 29 (10): 2013-2015

  Abstract

  Total femoral arthroplasty (TFA) is an option to amputation in the setting of excessive bones loss during revision total hip and knee arthroplasty. Twenty non-oncologic TFAs with a minimum of 2years follow-up were retrospectively reviewed. The average clinical follow-up was 73±49months. The incidence of new infection was 25% (5/20), while the overall infection rate was 35% (7/20). The incidence of primary hip instability was 10% (2/20), while the overall instability rate was 25% (5/20). Six patients (30%) required revision. The average pre-operative HHS was 30.2±13.1. The average post-operative HHS was 65.3±16.9. TFA is a viable alternative to amputation in non-oncologic patients with massive femoral bone deficiency. However, TFA performed poorly in the setting of infection and instability.

  View details for DOI 10.1016/j.arth.2014.05.012

  View details for Web of Science ID 000343159700024

  View details for PubMedID 25041874

• In Reply: Total Knee Arthroplasty After Lower Extremity Amputation: A Review of 13 Cases JOURNAL OF ARTHROPLASTY Amanatullah, D. F., Trousdale, R. T., Sierra, R. J. 2014; 29 (10): 2055-2055

  View details for DOI 10.1016/j.arth.2014.06.006

  View details for Web of Science ID 000343159700036

  View details for PubMedID 25070902

• Total knee arthroplasty after lower extremity amputation: a review of 13 cases. journal of arthroplasty Amanatullah, D. F., Trousdale, R. T., Sierra, R. J. 2014; 29 (8): 1590-1593

  Abstract

  Below knee amputation protects the ipsilateral knee from osteoarthritis and overloads the contralateral knee predisposing it to symptomatic osteoarthritis. We retrospectively reviewed 13 primary total knee arthroplasty (TKAs) in 12 patients with a prior lower extremity amputation. Twelve TKAs were performed on the contralateral side of the amputated limb while only one TKA was performed on the ipsilateral side. The average clinical follow-up was 6.8 ± 4.8 years. Knee Society Scores improved from 30.4 ± 11.8 to 88.5 ± 4.2 after TKA with a prior contralateral amputation. Three (23.1%) patients with TKA after contralateral amputation had aseptic loosening of the tibial component. Patients experience clinically significant improvement with TKA after lower extremity amputation. Augmentation of tibial fixation with a stem may be advisable during TKA after contralateral amputation.

  View details for DOI 10.1016/j.arth.2014.03.041

  View details for PubMedID 24836176

• Torsional Properties of Distal Femoral Cortical Defects ORTHOPEDICS Amanatullah, D. F., Williams, J. C., Fyhrie, D. P., Tamurian, R. M. 2014; 37 (3): 158-162

  Abstract

  The optimal management of pathologic long bone lesions remains a challenge in orthopedic surgery. The goal of the current study was to investigate the effect of defect depth on the torsional properties of the distal femur. A laterally placed distal metaphyseal cylindrical defect was milled in the cortex of the distal femur in 20 composite models. The proximal extent of the defects was constant. By decreasing the radius of the cylinder that intersected this predefined cord, 4 different radii defining 4 different depths of resection of the distal femur were created for testing: 17%, 33%, 50%, and 67% cortical defects, when normalized to the width of the femur at the level of resection. Each femur was mounted into a hydraulic axial/torsion materials testing machine and each specimen underwent torsional stiffness testing and torsional failure in external rotation. The specimens with less than a 33% cortical loss consistently demonstrated a superiorly oriented spiral fracture pattern, while the specimens with greater than a 50% cortical loss consistently demonstrated an inferiorly oriented transverse fracture pattern. The cortical defects were all statistically (P<.05) less stiff in torsion as the defect grew larger. There was a strong linear correlation between the mean torsional stiffness and cortical defect size (r(2)=0.977). This observation is supported by finite element analysis. The amount of femur remaining is crucial to stability. This biomechanical analysis predicts a critical loss of torsional integrity when a cortical defect approaches 50% of the width of the femur.

  View details for DOI 10.3928/01477447-20140225-51

  View details for Web of Science ID 000332601700025

  View details for PubMedID 24762144

• The financial impact of the loss of county indigent patient funding on a single orthopedic trauma surgery service JOURNAL OF TRAUMA AND ACUTE CARE SURGERY Forsh, D. A., Amanantullah, D. F., Coleman, S., Wolinsky, P. R. 2014; 76 (2): 529-533

  Abstract

  We examined the financial ramifications on the orthopedic trauma service after loss of payment to our institution for care of indigent patients. Our institution is the only Level I trauma center located within the county. Before mid-2009, county insurance-eligible patients treated at our institution had their health care paid for by the county. After mid-2009, the county no longer reimbursed our institution for care provided.A retrospective review was performed on 653 county patients treated by the four orthopedic trauma surgeons during a 4-year period including the 2 years before the loss of county payments as well as the 2-year period following the loss of payment. Data collected included demographics, admitting service, injuries treated, length of stay, surgeon billing, and reimbursement. We also classified the urgency of care that was rendered into one of three categories as follows: emergent, urgent, or elective.There was a higher frequency of emergent and urgent procedures and a lower frequency of elective cases performed in the noncontracted period versus the contracted period. During the contracted period, we billed and collected $1,161,036. After the loss of reimbursement from the county, we billed $870,590 and were paid $0. County reimbursements made up 33.5% of the total professional fees billed. There was a 20% net drop in total billing during the noncontracted period, of which the money not reimbursed by the county accounted for 31%.Despite the lack of county payment, our institution continues to provide care to the indigent population. This lack of payment may have significant long-term economic ramifications for the orthopedic trauma surgeons and for our institution. The financial burden preferentially falls on the "safety net" Level I trauma centers and the physicians who take care of patients with urgent and emergent injuries. This burden may be unsustainable in the future.Economic and value-based evaluation, level V.

  View details for DOI 10.1097/TA.0000000000000093

  View details for Web of Science ID 000336386100042

  View details for PubMedID 24458062

• Giant Cell Tumor of Bone ORTHOPEDICS Amanatullah, D. F., Clark, T. R., Lopez, M. J., Borys, D., Tamurian, R. M. 2014; 37 (2): 112-120

  Abstract

  EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Identify at-risk populations for giant cell tumor of bone. 2. Recognize the biology that drives giant cell tumor of bone. 3. Describe modern surgical and adjuvant techniques to effectively treat giant cell tumor of bone. 4. Recognize the complications associated with radiation therapy, poor resection, and adjuvant treatments. Giant cell tumor of bone (GCT) is a benign, locally aggressive bone tumor. Giant cell tumor of bone primarily affects the young adult patient population. The natural history of GCT is progressive bone destruction leading to joint deformity and disability. Surgery is the primary mode of treatment, but GCT has a tendency to recur locally despite a range of adjuvant surgical options. Pulmonary metastasis has been described. However, systemic spread of GCT rarely becomes progressive, leading to death. This review presents the clinicopathologic features of GCT and a historical perspective that highlights the current rationale and controversies regarding the treatment of GCT.

  View details for DOI 10.3928/01477447-20140124-08

  View details for Web of Science ID 000331879300031

  View details for PubMedID 24679193

• Non-oncologic Total Femoral Replacement: Retrospective Review Journal of Arthroplasty, epub ahead of print Amanatullah, D. F., Trousdale, R. T., Hanssen, A., Lewallen, D. G., Taunton, M. P. 2014
• Minimally Invasive Total Hip Arthroplasty Medscape http://emedicine.medscape.com/article/2000333-overview. Amanatullah, D. F., Di Cesare, P. E. 2014
• Total Hip Arthroplasty with and without Prior Periacetabular Osteotomy Clinical Orthopaedics and Related Research Amanatullah, D. F., Stryker, L., Schoenecker, P., Taunton, M. P., Clohish, J. C., Trousdale, R. T., Sierra, R. J. 2014
• Revision THA with Proximal Bone Deficiency using Fluted Tapered Modular Femoral Components. Bone and Joint Journal Amanatullah, D. F., Howard, J. L., Siman, H., Trousdale, R. T., Mabry, T. M., Berry, D. J. 2014
• Total Hip Arthroplasty after Lower Extremity Amputation Orthopedics Amanatullah, D. F., Trousdale, R. T., Sierra, R. J. 2014
• Peri-operative Management of the Total Knee: Patient Selection, Pain Management, Thromoprophylaxis, and Rehabilitation. Clinic Orthopaedic Practice. Amanatullah, D. F., Pallante, G., Paganano, M. W., Sierra, R. J. 2014
• Removal of Well-fixed Implants. Operative Techniques in Orthopaedic Surgery, 2nd Edition, awaiting publication Amanatullah, D. F., Pagnano, M. W. 2014
• Femoroacetabular Impingement: Current Concepts in Diagnosis and Treatment. Orthopedics, accepted, CME Amanatullah, D. F., Antkowiak, T., Pillay, K., Refaat, M., Jamali, A. A. 2014
• Effect of Heterotopic Ossification on Hip Range of Motion and Clinical Outcome Journal of Arthroplasty, accepted Vasileiadis, G. I., Amanatullah, D. F., Crenshaw, J., Pudillo, L., Taunton, M. P., Kaufman., K. 2014
• Distinct Patterns of Gene Expression in the Superficial, Middle and Deep Zones of Bovine Articular Cartilage Journal of Tissue Engineering and Regenerative Medicine Amanatullah, D. F., Yamane, S., Reddi , A. H. 2014; 8 (7)
• Total Hip Arthroplasty in Down Syndrome Bone and Joint Journal, accepted Amanatullah, D. F., Rachala, R., Sierra, R. J. 2014
• Minimally Invasive Total Hip Arthroplasty Medscape http://emedicine.medscape.com/article/2000333-overview. Amanatullah, D. F., Di Cesare, P. E. 2014
• Brachial Artery Avulsion Complicating a Supracondylar Humerus Fracture: A Case Report and Review Current Orthopaedic Practice Sheridan, K., Amanatullah, D. F., Voightlander, J. P., Ertl, J., Moehring, D. 2014; 25
• Giant Cell Tumor of Bone: Current Concepts in Diagnosis and Treatment. Orthopedics Amanatullah, D. F., Clark, T. R., Lopez, M. J., Borys, D., Tamurian, R. M. 2014; 37
• Recurrent Carpal Tunnel Syndrome Presenting with the Median Nerve Superficial to the Transverse Carpal Ligament Orthopedics, accepted Amanatullah, D. F., Gaskin, A., Allen, R. H. 2014
• Total Hip Arthroplasty after Lower Extremity Amputation Orthopedics Amanatullah, D. F. 2014
• Acetabular Fractures: What Radiologists Should Know and How 3D CT Images Can Aid Classification. RadioGraphics, accepted Scheinfeld , M., Amanatullah, D. F. 2014
• Similar Clinical Outcomes for Total Hip Arthroplasty with and without Prior Periacetabular Osteotomy Clinical Orthopaedics and Related Research, accpted Amanatullah, D. F., Stryker, L., Schoenecker, P., Taunton, M. P., Clohisy, J. C., Trousdale, R. T., Sierra, R. J. 2014
• Pre-operative Planning for the Adult Hip The Adult Hip, awaiting publication Pereira, G. C., Amanatullah, D. F., Di Ceasare, P. E. 2014
• Failure of a constrained acetabular liner without reinforcement ring disruption. American journal of orthopedics (Belle Mead, N.J.) Arthur, J. A., Amanatullah, D. F., Kennedy, G. D., Di Cesare, P. E. 2013; 42 (12): 566-568

  Abstract

  Several risk factors for dislocation after total hip arthroplasty (THA) have been identified including operative-, patient-, and implant-related factors. The following case report describes the dislocation of a revision THA without disruption of the constrained liner or containment ring. The possible mechanisms leading to this type of failure include lever-out impingement and poor abductor function, or tension secondary to prior surgery. Dislocation without disruption of containment ring has not been described for the Pinnacle Acetabular Cup with the Enhanced Stability Constrained Liner (DePuy Orthopaedics, Warsaw, Indiana).

  View details for PubMedID 24471147

• Identification of the Landmark Registration Safe Zones During Total Knee Arthroplasty Using an Imageless Navigation System JOURNAL OF ARTHROPLASTY Amanatullah, D. F., Di Cesare, P. E., Meere, P. A., Pereira, G. C. 2013; 28 (6): 938-942

  Abstract

  Incorrect registration during computer assisted total knee arthroplasty (CA-TKA) leads to malposition of implants. Our aim was to evaluate the tolerable error in anatomic landmark registration. We incorrectly registered the femoral epicondyles, femoral and tibial centers, as well as the malleoli and documented the change in angulation or rotation. We found that the distal femoral epicondyles were the most difficult anatomic landmarks to register. The other bony landmarks were more forgiving. Identification of the distal femoral epicondyles has a high inter-observer and intra-observer variability. Our observation that there is less than 2mm of safe zone in the anterior or posterior direction during registration of the medial and lateral epicondyles may explain the inability of CA-TKA to improve upon the outcomes of conventional TKA.

  View details for DOI 10.1016/j.arth.2012.12.013

  View details for Web of Science ID 000319846400013

  View details for PubMedID 23566700

• c-Maf Transcription Factor Regulates ADAMTS-12 Expression in Human Chondrogenic Cells CARTILAGE Hong, E., Yik, J., Amanatullah, D. F., Di Cesare, P. E., Haudenschild, D. R. 2013; 4 (2): 177-186

  Abstract

  ADAMTS (a disintegrin and metalloproteinase with thrombospondin type-1 motif) zinc metalloproteinases are important during the synthesis and breakdown of cartilage extracellular matrix. ADAMTS-12 is up-regulated during in vitro chondrogenesis and embryonic limb development; however, the regulation of ADAMTS-12 expression in cartilage remains unknown. The transcription factor c-Maf is a member of Maf family of basic ZIP (bZIP) transcription factors. Expression of c-Maf is highest in hypertrophic chondrocytes during embryonic development and postnatal growth. We hypothesize that c-Maf and ADAMTS-12 are co-expressed during chondrocyte differentiation and that c-Maf regulates ADAMTS-12 expression during chondrogenesis.Promoter analysis and species alignments identified potential c-Maf binding sites in the ADAMTS-12 promoter. c-Maf and ADAMTS-12 co-expression was monitored during chondrogenesis of stem cell pellet cultures. Luciferase expression driven by ADAMTS-12 promoter segments was measured in the presence and absence of c-Maf, and synthetic oligonucleotides were used to confirm specific binding of c-Maf to ADAMTS-12 promoter sequences.In vitro chondrogenesis from human mesenchymal stem cells revealed co-expression of ADAMTS-12 and c-Maf during differentiation. Truncation and point mutations of the ADAMTS-12 promoter evaluated in reporter assays localized the response to the proximal 315 bp of the ADAMTS-12 promoter, which contained a predicted c-Maf recognition element (MARE) at position -61. Electorphoretic mobility shift assay confirmed that c-Maf directly interacted with the MARE at position -61.These data suggest that c-Maf is involved in chondrocyte differentiation and hypertrophy, at least in part, through the regulation of ADAMTS-12 expression at a newly identified MARE in its proximal promoter.

  View details for DOI 10.1177/1947603512472697

  View details for Web of Science ID 000209218300008

  View details for PubMedID 26069660

• Subtrochanteric Fracture Following Removal of a Porous Tantalum Implant Case Reports in Orthopedics Amanatullah, D. F., Farac, R., McDonald, T. J., Moehring, H. D., Di Cesare, P. E. 2013
• Minimally Invasive Total Knee Arthroplasty Medscape http://emedicine.medscape.com/article/2000356-overview. Amanatullah, D. F., Di Cesare, P. E. 2013
• c-MAF Transcription Factor Regulates ADAMTS-12 Expression in Human Chondrocytes Cartilage Hong, E., Yik, J., Amanatullah, D. F., Di Cesare, P. E., Haudenschild, D. R. 2013; 4
• Minimally Invasive Total Knee Arthroplasty Medscape Amanatullah, D. F. 2013
• Wound Complications Surgery of the Hip Cheung, Y., Amanatullah, D. F., Di Cesare, P. E. 2013
• Case Report: Artificial Elevation of Prothrombin Time by Telavancin, Clinical Orthopaedics and Related Research Clinical Orthopaedics and Related Research Amanatullah, D. F., Lopez, M., Gosselin, R., Gupta, M. 2013; 471
• Free vascularized fibular transfer with langenskiöld procedure for the treatment of congenital pseudarthrosis of the forearm. Techniques in Hand and Upper Extremity Surgery Bauer, A. S., Singh, A. K., Amanatullah, D. F., Lerman, J. A., James, M. A. 2013; 17
• The application of minimally invasive surgical techniques. Part I: total hip arthroplasty. American journal of orthopedics (Belle Mead, N.J.) Amanatullah, D. F., Burrus, M. T., Sathappan, S. S., Levine, B., Di Cesare, P. E. 2012; 41 (10): E134-9

  Abstract

  Traditional surgical approaches often involve making large skin incisions and extensively dissecting healthy tissue to access diseased anatomy. Obviously more desirable is to make smaller incisions and more focused dissections and achieve the same postsurgical outcomes. Minimally invasive surgery (MIS) is gaining popularity in many orthopedic fields, but MIS techniques are not without risk. Continued use of these techniques is a topic of debate. If satisfactory alignment is satisfactory with MIS, and if the complication rates of MIS are similar to those of traditional approaches, it seems sensible to consider the less invasive approaches to enable earlier patient recovery and improve cosmesis. Skeptics claim that there is no advantage in using MIS over time-tested approaches and are concerned that MIS approaches are being implemented before being properly subjected to peer review.

  View details for PubMedID 23376994

• The application of minimally invasive surgical techniques. Part II: total knee arthroplasty. American journal of orthopedics (Belle Mead, N.J.) Amanatullah, D. F., Burrus, M. T., Sathappan, S. S., Levine, B., Di Cesare, P. E. 2012; 41 (10): E140-4

  Abstract

  Traditional surgical approaches often involve making large skin incisions and extensively dissecting healthy tissue to access diseased anatomy. Obviously more desirable is to make smaller incisions and more focused dissections and achieve the same postsurgical outcomes. Minimally invasive surgery (MIS) is gaining popularity in many orthopedic fields, but MIS techniques are not without risk. Continued use of these techniques is a topic of debate. If alignment is satisfactory with MIS, and if the complication rates of MIS are similar to those of traditional approaches, it seems sensible to consider the less invasive approaches to enable earlier patient recovery and improve cosmesis. Skeptics claim that there is no advantage in using MIS over time-tested approaches and are concerned that MIS approaches are being implemented before being properly subjected to peer review.

  View details for PubMedID 23376995

• Identification of a 3Kbp Mechanoresponsive Promoter Region in the Human Cartilage Oligomeric Matrix Protein Gene TISSUE ENGINEERING PART A Amanatullah, D. F., Lu, J., Hecht, J., Posey, K., Yik, J., Di Cesare, P. E., Haudenschild, D. R. 2012; 18 (17-18): 1882-1889

  Abstract

  Expression of chondrocyte-specific genes is regulated by mechanical force. However, despite the progress in identifying the signal transduction cascades that activate expression of mechanoresponsive genes, little is known about the transcription factors that activate transcription of mechanoresponsive genes. The DNA elements that confer mechanoresponsiveness within a cartilage gene promoter have yet to be identified. We have established an experimental system to identify the DNA elements and transcription factors that mediate the mechanoresponse of a promoter to nominal compressive stress in primary human chondrocytes and stem cells in a three-dimensional culture system. Our results demonstrate that the proximal 3 Kb of the human cartilage oligomeric matrix protein promoter is sufficient to mediate a mechanoresponse in human articular chondrocytes and stem cells, and that the magnitude of mechanoresponse correlates to the regulation of the endogenous gene at the RNA and protein level. This information is critical to understanding how mechanical force regulates the transcriptional activation of cartilage genes in three-dimensional culture.

  View details for DOI 10.1089/ten.tea.2011.0497

  View details for Web of Science ID 000308704600014

  View details for PubMedID 22764748

• Effect of mini-fragment fixation on the stabilization of medial malleolus fractures JOURNAL OF TRAUMA AND ACUTE CARE SURGERY Amanatullah, D. F., McDonald, E., Shellito, A., Lafazan, S., Cortes, A., Curtiss, S., Wolinsky, P. R. 2012; 72 (4): 948-953

  Abstract

  Oblique fractures of the medial malleolus can arise from the application of axial force at various anatomic positions of the ankle, including supination-external rotation, pronation-external rotation, or pronation abduction. Although a variety of techniques exist to provide fixation of horizontal medial malleolus fractures, the optimal technique and pattern for internal fixation remains unclear. The aim of this study was to evaluate the mechanical properties of four different fixation methods for fractures of the medial malleolus.Identical oblique osteotomies were created in synthetic distal tibiae using a jig. The specimens were divided into four fixation groups: contoured 2.0 mm mini-fragment T-plate, figure-of-eight tension band wire, construct two parallel 4.0 mm cancellous screws, and two divergent 4.0 mm cancellous screws. The specimens were tested using offset axial tension at 10 mm/min until 2 mm of joint line displacement.The average stiffness in tension and force at 2 mm of joint line displacement of the plate construct was significantly greater than any of the other constructs (p < 0.05), whereas the average stiffness in tension of the other three groups were not significantly different from each other (p > 0.05).Using a contoured 2.0 mm mini-fragment T-plate as the method of fixation resulted in an at least 25% stiffer construct during tension and required at least 24% more force for 2 mm of joint line displacement when compared with more traditional methods of fixation in an osteotomy model of an oblique medial malleolus fracture.

  View details for DOI 10.1097/TA.0b013e318249697d

  View details for Web of Science ID 000302784600033

  View details for PubMedID 22491610

• Effect of divergent screw fixation in vertical medial malleolus fractures JOURNAL OF TRAUMA AND ACUTE CARE SURGERY Amanatullah, D. F., Khan, S. N., Curtiss, S., Wolinsky, P. R. 2012; 72 (3): 751-754

  Abstract

  This study qualified and evaluated the mechanical properties of three different screw orientations used for fixation of vertical shear fractures of the medial malleolus.Identical vertical osteotomies were created in synthetic distal tibiae using a jig. The specimens were assigned to one of the three fixation groups (n = 8 per group): (1) parallel: two 40 mm length, 4.0 mm diameter screws placed parallel to each other in the transverse plane; (2) convergent: two 40 mm length, 4.0 mm diameter screws placed 25 degree convergent to each other in the transverse plane; and (3) divergent: two 40 mm length, 4.0 mm diameter screws placed 15 degree divergent to each other in the transverse plane. The specimens were tested using offset axial loading at 1 mm/s until 2 mm of displacement.The average stiffness was 102 N/mm ± 51 N/mm for the parallel group, 109 N/mm ± 37 N/mm for the convergent group, and 185 N/mm ± 73 N/mm for the divergent group. The average stiffness of the divergent group was significantly greater than either the parallel (p < 0.05) or convergent (p < 0.05) groups. The divergent group was 81.4% more stiff than the parallel group and 69.7% more stiff than the convergent group. The average load at 2 mm of displacement was 324 N ± 87 N for the parallel group, 373 N ± 95 N for the convergent group, and 512 N ± 170 N for the divergent group. The average load at failure of the divergent group was significantly (p < 0.05) greater than the parallel groups. The divergent group was required 58.0% more force at 2 mm of displacement than the parallel group and 37.3% more force at 2 mm of displacement than the convergent group.The use of a divergent screw pattern resulted in a stiffer fixation construct that requires more force for 2 mm of displacement when used to stabilize an osteotomy model of vertical shear medial malleolus fractures.

  View details for DOI 10.1097/TA.0b013e31823b8b9f

  View details for Web of Science ID 000301371100046

  View details for PubMedID 22491565

• Patellar Polyethylene Spinout After Low-contact Stress, High-congruity, Mobile-bearing Patellofemoral Arthroplasty ORTHOPEDICS Amanatullah, D. F., Jamali, A. A. 2012; 35 (2): E272-E276

  Abstract

  A low-contact stress, high-congruity, mobile-bearing patellofemoral joint arthroplasty decreases the contact force in the patellofemoral joint, theoretically reducing patellar polyethylene wear and increasing implant longevity. This article describes the case of a 47-year-old obese woman who presented with pain and loss of extension after a low-contact stress, high-congruity, mobile-bearing patellofemoral joint arthroplasty. Radiographs revealed dislocation (ie, spinout) of the patellar polyethylene. Patellar polyethylene spinout is a rare complication of metal-backed, mobile-bearing patellar resurfacing. Theoretically, patellar polyethylene spinout in low-contact stress, high-congruity, mobile-bearing patellofemoral arthroplasty is related to implant design and the placement of the metal base plate. Ultimately, the articulation of low-contact stress, high-congruity, mobile-bearing patellofemoral arthroplasty may be too congruent to resist the forces of the patellofemoral joint, particularly in patients who are obese, and the patellar rotation allowed by this articulation may not be sufficient for all patients. Should patellar spinout occur, replacement of the polyethylene is not sufficient to correct the problem; hence, revision of the patellar and trochlear components is required because it remains unclear whether failure is secondary to patellar or trochlear design deficiencies.

  View details for DOI 10.3928/01477447-20120123-27

  View details for Web of Science ID 000300057300025

  View details for PubMedID 22310419

• Right Elbow Pain in a 21-year-old Pregnant Female Shoulder and Elbow Amanatullah, D. F., Bozzio, A. E., Mallon, Z. O., Mak, W. H., Borys, D., Tamurian, R. M. 2012; 4
• Minimally Invasive Total Hip Arthroplasty Medscape Drugs and Disease, http://emedicine.medscape.com/article/2000333-overview. Amanatullah, D. F., Joice, M., Di Cesare, P. E. 2012
• Surgical Intern Survival Guide Einstein Journal of Biology and Medicine Amanatullah, D. F. 2012; 27: 34-37
• Identification of a Mechanoresponsive 3 Kb Promoter Region in the Human Cartilage Oligomeric Matrix Protein Gene. Tissue Engineering Part A Amanatullah, D. F., Lu, J., Hecht, J., Posey, K., Yik, J., Di Cesare, P. E., Haudenschild, D. R. 2012; 18
• Intermediate-Term Radiographic and Patient Outcomes in Revision Hip Arthroplasty With a Modular Calcar Design and Porous Plasma Coating JOURNAL OF ARTHROPLASTY Amanatullah, D. F., Meehan, J. P., Cullen, A. B., Kim, S. H., Jamali, A. A. 2011; 26 (8): 1451-1454

  Abstract

  This study is a retrospective evaluation of the intermediate-term results of 26 consecutive revision total hip arthroplasties performed with a modular titanium, uncemented femoral component. The average patient age at the time of revision total hip arthroplasty was 72 years, and there were an equal number of males and females. The mean follow-up was 5.7 years (ranging from 4 to 11 years). No re-revision was necessary during this follow-up time. The mean Harris hip score improved significantly (preoperative and postoperative score was 50.7 and 89.6, respectively; P < .001). Postoperatively, Short Form 36 functional scores averaged 67.7 across 9 functional parameters. Our observed low revision rate and favorable patient-reported outcome scores support the continuous use of modular titanium, uncemented femoral components in revision total hip arthroplasty.

  View details for DOI 10.1016/j.arth.2010.12.026

  View details for Web of Science ID 000297389100052

  View details for PubMedID 21497483

• Current management options for osteonecrosis of the femoral head: part II, operative management. American journal of orthopedics (Belle Mead, N.J.) Amanatullah, D. F., Strauss, E. J., Di Cesare, P. E. 2011; 40 (10): E216-25

  Abstract

  Osteonecrosis of the femoral head is a multifactorial disease that can result in significant clinical morbidity and affects patients of any age, including young and active patients. Late sequelae of femoral head osteonecrosis include femoral head collapse and subsequent degeneration of the hip joint. A high index of suspicion and improved radiographic evaluation allow orthopedic surgeons to identify this disease at an earlier stage. Current management options for hip osteonecrosis have results that vary according to patient population and disease stage. Modifications of older techniques, as well as emerging technologies, have led to the development of management strategies that may be able to alter the course of femoral head osteonecrosis.

  View details for PubMedID 22263205

• Comparison of Surgical Outcomes and Implant Wear Between Ceramic-Ceramic and Ceramic-Polyethylene Articulations in Total Hip Arthroplasty JOURNAL OF ARTHROPLASTY Amanatullah, D. F., Landa, J., Strauss, E. J., Garino, J. P., Kim, S. H., Di Cesare, P. E. 2011; 26 (6): 72-77

  Abstract

  The results of a prospective multicenter trial comparing 357 hips randomized to total hip arthroplasty with either ceramic-ceramic or ceramic-polyethylene couplings are presented. No statistically significant difference in clinical outcomes scores between the ceramic-ceramic and ceramic-polyethylene groups was observed at any time interval. The mean linear rate was statistically lower (P < .001) in the ceramic-ceramic group (30.5 μm/year) when compared with the ceramic-polyethylene group (218.2 μm/year). The rates of ceramic implant fracture (2.6%) and audible component-related noise (3.1%) were statistically higher in the ceramic-ceramic group when compared with the ceramic-polyethylene group (P < .05). Lastly, there was no statistically significant difference in the dislocation or revision rate between the groups at the time of last clinical follow-up.

  View details for DOI 10.1016/j.arth.2011.04.032

  View details for Web of Science ID 000294393000014

  View details for PubMedID 21680138

• Current management options for osteonecrosis of the femoral head: part 1, diagnosis and nonoperative management. American journal of orthopedics (Belle Mead, N.J.) Amanatullah, D. F., Strauss, E. J., Di Cesare, P. E. 2011; 40 (9): E186-92

  Abstract

  Osteonecrosis of the femoral head is a multifactorial disease that can result in significant clinical morbidity and affects patients of any age, including young and active patients. Late sequelae of femoral head osteonecrosis include femoral head collapse and subsequent degeneration of the hip joint. A high index of suspicion and improved radiographic evaluation allow orthopedic surgeons to identify this disease at an earlier stage. Current management options for hip osteonecrosis have results that vary according to patient population and disease stage. Modifications of older techniques, as well as emerging technologies, have led to the development of management strategies that may be able to alter the course of femoral head osteonecrosis.

  View details for PubMedID 22022684

• Pelvic osteoid osteoma in a skeletally mature female. American journal of orthopedics (Belle Mead, N.J.) Amanatullah, D. F., Mallon, Z. O., Mak, W. H., Borys, D., Tamurian, R. M. 2011; 40 (9): 476-478

  Abstract

  Osteoid osteoma is the most common bone-producing tumor that typically presents with "throbbing night pain" and that improves dramatically with use of low-dose salicylates. Few cases of pelvic osteoid osteoma have been reported, and most have involved patients younger than age 30. Surgical excision classically has been the treatment of choice, but, recently, less invasive modalities, including radiofrequency ablation, have begun to supplant surgical management of osteoid osteoma, resulting in a decrease in the need for definitive surgical diagnosis and treatment. We present a rare case of osteoid osteoma in the pelvis of a woman older than age 30.

  View details for PubMedID 22022677

• Applying computer-assisted navigation techniques to total hip and knee arthroplasty. American journal of orthopedics (Belle Mead, N.J.) Amanatullah, D. F., Burrus, M. T., Sathappan, S. S., Levine, B., Di Cesare, P. E. 2011; 40 (8): 419-426

  Abstract

  Appropriate implant alignment is a major goal of total joint arthroplasty. Obtaining appropriate alignment typically involves making intraoperative decisions in response to visual and tactile feedback. Integrated computer-based systems provide the option of continuous real-time feedback and offer the potential to decrease intraoperative errors while enhancing the surgical learning experience. Computer-assisted orthopedic surgery helps the surgeon perform both intraoperative and postoperative technical audits of implant alignment. Improving implant alignment can be correlated with improved long-term clinical outcomes. However, despite emerging data, many surgeons remain wary of computer-assisted orthopedic surgery.

  View details for PubMedID 22016871

• Biomechanical properties of volar hybrid and locked plate fixation in distal radius fractures. journal of hand surgery Sokol, S. C., Amanatullah, D. F., Curtiss, S., Szabo, R. M. 2011; 36 (4): 591-597

  Abstract

  We compare the biomechanical properties of a volar hybrid construct to an all-locking construct in an osteoporotic and normal comminuted distal radius fracture model.Groups of 28 normal, 28 osteoporotic, and 28 over-drilled osteoporotic left distal radius synthetic bones were used. The normal group consisted of synthetic bone with a standard foam core. The osteoporotic group consisted of synthetic bone with decreased foam core density. The over-drilled osteoporotic group consisted of synthetic bone with decreased foam core density and holes drilled with a 2.3 mm drill, instead of the standard 2.0 mm drill, to simulate the lack of purchase in osteoporotic bone. Within each group, 14 synthetic bones were plated with a volar locking plate using an all-locking screw construct, and 14 synthetic bones were plated with a volar locking plate using a hybrid screw construct (ie, both locking and nonlocking screws). A 1-cm dorsal wedge osteotomy was created with the apex 2 cm from the volar surface of the lunate facet. Each specimen was mounted to a materials testing machine, using a custom-built, standardized axial compression jig. Axial compression was delivered at 1 N/s over 3 cycles from 20 N to 100 N to establish stiffness. Each sample was stressed to failure at 1 mm/s until 5 mm of permanent deformation occurred.Our results show no difference in construct stiffness and load at failure between the all-locking and hybrid constructs in the normal, osteoporotic, or over-drilled osteoporotic synthetic bone models. All specimens failed by plate bending at the osteotomy site with loss of height.Although volar locking plates are commonly used for the treatment of distal radius fractures, the ideal screw configuration has not been determined. Hybrid fixation has comparable biomechanical properties to all locking constructs in the fixation of metaphyseal fractures about the knee and shoulder and might also have a role in the fixation of distal radius fractures.

  View details for DOI 10.1016/j.jhsa.2010.12.032

  View details for PubMedID 21463723

• Biomechanical Properties of Volar Hybrid and Locked Plate Fixation in Distal Radius Fractures JOURNAL OF HAND SURGERY-AMERICAN VOLUME Sokol, S. C., Amanatullah, D. F., Curtiss, S., Szabo, R. M. 2011; 36A (4): 591-597

  View details for DOI 10.1016/j.jhsa.2010.12.032

  View details for Web of Science ID 000289493300004

• Transverse Deficiency in the Upper Limb Orthopaedic Knowledge Update: Pediatrics James, M. A., Amanatullah, D. F. 2011
• Intermediate-term Radiographic Patient Outcomes in Revision Hip Arthroplasty with a Modular Calcar Design and Plasma Porous Coating Journal of Arthroplasty Amanatullah, D. F., Meehan, J. P., Cullen, A. B., Kim, S. H., Jamali, A. A. 2011; 26
• Current Treatment Options for Osteonecrosis of the Femoral Head: Part 1, Diagnosis and Nonoperative Management. American Journal of Orthopedics Amanatullah, D. F., Strauss, E. J., Di Cesare, P. E. 2011; 40
• Current Treatment Options for Osteonecrosis of the Femoral Head: Part II, Operative Management American Journal of Orthopedics Amanatullah, D. F., Strauss, E. J., Di Cesare, P. E. 2011; 40
• Progression of aggressive metastatic carcinosarcoma after treatment of epithelioid osteosarcoma. Orthopedics Amanatullah, D. F., Ngann, K. K., Borys, D., Tamurian, R. M. 2010; 33 (6): 445-?

  Abstract

  Osteosarcoma is the most common primary malignant osseous neoplasm, constituting approximately 35% of skeletal malignancies. The different subtypes of osteosarcoma are differentiated based on clinical, histologic, and radiographic data, as well as the variable amount of osteoid produced by malignant cells. The epithelioid osteosarcoma subtype accounts for only 5.7% of all osteosarcomas and portends an extremely poor prognosis. The 5-year survival rate for patients with epithelioid osteosarcoma treated with surgery (with or without chemotherapy) is 13.5%. This is in direct contrast to the >70% ten-year survival rate of conventional osteosarcoma treated with surgery and chemotherapy. This article presents a fatal case of epithelioid osteosarcoma in an 11-year-old girl with right knee pain of 6 months' duration. Biopsy demonstrated morphologic findings consistent with high-grade osteosarcoma with epithelioid features. The epithelioid component was positive for vimentin and CD99; however, fluorescent in situ hybridization for the (11;22) translocation was negative. In this case, the epithelioid cells failed to respond to conventional or subsequent experimental chemotherapy for osteosarcoma and eventual metastasized to the lymph nodes and lungs despite multiple ablative surgeries. This case report supports the concept of carcinosarcoma with malignant cells lines arising from 2 different cellular lineages or a common cellular precursor. The epithelial component was more aggressive than the cells of mesenchymal origin, highlighting the need for continued research and a more favorable outcome for this rare subset of osteosarcoma.

  View details for DOI 10.3928/01477447-20100429-26

  View details for PubMedID 20806764

• Hip Resurfacing Arthroplasty: A Review of the Evidence for Surgical Technique, Outcome, and Complications ORTHOPEDIC CLINICS OF NORTH AMERICA Amanatullah, D. F., Cheung, Y., Di Cesare, P. E. 2010; 41 (2): 263-?

  Abstract

  Hip resurfacing arthroplasty has reemerged as a valid reconstruction option for the osteoarthritic hip. Patient selection is critical for excellent surgical outcomes, especially when compared with total hip arthroplasty. However, concerns regarding surgical technique and postsurgical complications persist. The authors review the evidence for surgical technique, outcomes, and complications related to modern metal-on-metal hip resurfacing arthroplasty.

  View details for DOI 10.1016/j.ocl.2010.01.002

  View details for Web of Science ID 000277461800015

  View details for PubMedID 20399365

• Alternative Fixation for Small Medial Malleolus Fractures Orthopedics Amanatullah, D. F., Wolinsky, P. R. 2010; 33
• Selection of Aggressive Metastatic Carcinoma after Treatment of Epithelioid Osteosarcoma Orthopedics Amanatullah, D. F., Ngann, K. K., Borys, D., Tamurian, R. M. 2010; 33
• PU.1 inhibits the erythroid program by binding to GATA-1 on DNA and creating a repressive chromatin structure EMBO JOURNAL Stopka, T., Amanatullah, D. F., Papetti, M., Skoultchi, A. I. 2005; 24 (21): 3712-3723

  Abstract

  Transcriptional repression mechanisms are important during differentiation of multipotential hematopoietic progenitors, where they are thought to regulate lineage commitment and to extinguish alternative differentiation programs. PU.1 and GATA-1 are two critical hematopoietic transcription factors that physically interact and mutually antagonize each other's transcriptional activity and ability to promote myeloid and erythroid differentiation, respectively. We find that PU.1 inhibits the erythroid program by binding to GATA-1 on its target genes and organizing a complex of proteins that creates a repressive chromatin structure containing lysine-9 methylated H3 histones and heterochromatin protein 1. Although these features are thought to be stable aspects of repressed chromatin, we find that silencing of PU.1 expression leads to removal of the repression complex, loss of the repressive chromatin marks and reactivation of the erythroid program. This process involves incorporation of the replacement histone variant H3.3 into nucleosomes. Repression of one transcription factor bound to DNA by another transcription factor not on the DNA represents a new mechanism for downregulating an alternative gene expression program during lineage commitment of multipotential hematopoietic progenitors.

  View details for DOI 10.1038/sj.emboj.7600834

  View details for Web of Science ID 000233118500004

  View details for PubMedID 16222338

• Eat to Live: The Revolutionary Formula for Fast and Sustained Weight Loss Einstein Journal of Biology and Medicine Amanatullah, D. F. 2004; 21
• The cell cycle in steroid hormone regulated proliferation and differentiation. Minerva endocrinologica Amanatullah, D. F., Zafonte, B. T., Pestell, R. G. 2002; 27 (1): 7-20

  Abstract

  Steroid hormones mediate pleiotropic cellular processes involved in metabolism, cellular proliferation, and differentiation. The ability of the cell to respond to its hormonal environment is transduced by nuclear receptors (NRs) that bind both hormone and DNA. Hence, NRs represent a link between the external hormonal milieu and the genes that control cell physiology. Therefore, understanding the effects of steroid hormones on proliferation and differentiation requires a knowledge of the cell cycle, the interaction of NRs at the level of transcription, and the potential areas of cross-talk between these two.

  View details for PubMedID 11845110

• The Importance of a Physician's Wit: A Critical Analysis of Science in Medicine Einstein Quarterly Journal of Biology and Medicine Amanatullah, D. F. 2002; 19
• Translational Research: From the Bench to the Bedside and Back Einstein Quarterly Journal of Biology and Medicine Amanatullah, D. F. 2001; 18
• Ras Regulation of Cyclin D1 Promoter. Methods in Enzymology Amanatullah, D. F., Zafonte, B. T., Albanese, C., Fu, M., Messiers, C., Hassell, J., Pestell, R. G. 2001; 333
• Ras Regulation of Cyclin-dependent Immunoprecipitation Kinase Assays Methods in Enzymology Zafonte, B. T., Amanatullah, D. F., Sage, D., Augenlicht, L. H., Pestell, R. G. 2001; 333
• Cell-cycle dysregulation in breast cancer: Breast cancer therapies targeting the cell cycle FRONTIERS IN BIOSCIENCE Zafonte, B. T., Hulit, J., Amanatullah, D. F., Albanese, C., Wang, C. G., Rosen, E., Reutens, A., Sparano, J. A., Lisanti, M. P., Pestell, R. G. 2000; 5: D938-D961

  Abstract

  Breast cancer is the most commonly diagnosed cancer in American women. The underlying mechanisms that cause aberrant cell proliferation and tumor growth involve conserved pathways, which include components of the cell cycle machinery. Proto-oncogenes, growth factors, and steroids have been implicated in the pathogenesis of breast cancer. Surgery, local irradiation, and chemotherapy have been the mainstay of treatment for early and advanced stage disease. Potential targets for selective breast cancer therapy are herein reviewed. Improved understanding of the biology of breast cancer has led to more specific "targeted therapies" directed at biological processes that are selectively deregulated in the cancerous cells. Examples include tamoxifen for estrogen receptor positive tumors and imunoneutralizing antibodies such as trastuzumab for Her2/neu overexpressing tumors. Other novel anticancer agents such as paclitaxel, a microtubule binding molecule, and flavopiridol, a cyclin dependent kinase inhibitor, exert their anticancer effects by inhibiting cell cycle progression.

  View details for Web of Science ID 000166736900004

  View details for PubMedID 11102317

• The integrin-linked kinase regulates the cyclin D1 gene through glycogen synthase kinase 3 beta and cAMP-responsive element-binding protein-dependent pathways JOURNAL OF BIOLOGICAL CHEMISTRY D'Amico, M., Hulit, J., Amanatullah, D. F., Zafonte, B. T., Albanese, C., Bouzahzah, B., Fu, M. F., Augenlicht, L. H., Donehower, L. A., Takemaru, K. I., MOON, R. T., Davis, R., Lisanti, M. P., Shtutman, M., Zhurinsky, J., Ben-Ze'Ev, A., Troussard, A. A., Dedhar, S., Pestell, R. G. 2000; 275 (42): 32649-32657

  Abstract

  The cyclin D1 gene encodes the regulatory subunit of a holoenzyme that phosphorylates and inactivates the pRB tumor suppressor protein. Cyclin D1 is overexpressed in 20-30% of human breast tumors and is induced both by oncogenes including those for Ras, Neu, and Src, and by the beta-catenin/lymphoid enhancer factor (LEF)/T cell factor (TCF) pathway. The ankyrin repeat containing serine-threonine protein kinase, integrin-linked kinase (ILK), binds to the cytoplasmic domain of beta(1) and beta(3) integrin subunits and promotes anchorage-independent growth. We show here that ILK overexpression elevates cyclin D1 protein levels and directly induces the cyclin D1 gene in mammary epithelial cells. ILK activation of the cyclin D1 promoter was abolished by point mutation of a cAMP-responsive element-binding protein (CREB)/ATF-2 binding site at nucleotide -54 in the cyclin D1 promoter, and by overexpression of either glycogen synthase kinase-3beta (GSK-3beta) or dominant negative mutants of CREB or ATF-2. Inhibition of the PI 3-kinase and AKT/protein kinase B, but not of the p38, ERK, or JNK signaling pathways, reduced ILK induction of cyclin D1 expression. ILK induced CREB transactivation and CREB binding to the cyclin D1 promoter CRE. Wnt-1 overexpression in mammary epithelial cells induced cyclin D1 mRNA and targeted overexpression of Wnt-1 in the mammary gland of transgenic mice increased both ILK activity and cyclin D1 levels. We conclude that the cyclin D1 gene is regulated by the Wnt-1 and ILK signaling pathways and that ILK induction of cyclin D1 involves the CREB signaling pathway in mammary epithelial cells.

  View details for Web of Science ID 000090003800039

  View details for PubMedID 10915780

• Cell-cycle dysregulation and the molecular mechanisms of prostate cancer FRONTIERS IN BIOSCIENCE-LANDMARK Amanatullah, D. F., Reutens, A. T., Zafonte, B. T., Fu, M. F., Mani, S., Pestell, R. G. 2000; 5: D372-D390

  Abstract

  Prostate cancer is the most common cause of non-cutaneous cancer in men and although frequently latent is the second commonest cause of death. Screening for the disease was historically based on symptoms of urethral obstruction, clinical examination of the prostate gland and serum measurements of prostate specific antigen. As prostate cancer growth in the early stages is enhanced by androgens, the mainstay of therapy has been androgen ablation by pharmaco-therapeutic or surgical means. The subsequent development of androgen therapy resistant prostate cancer in many patients, for whom therapeutic options remain limited, has led researchers to focus attention on understanding the molecular genetics of prostate cancer. The array of genetic abnormalities observed in prostate tumors, which include changes in components of the cell cycle, suggest the disease is quite heterogeneous and may require further sub-classification based on genetic markers. Such analyses may lead to identification of relevant new prognostic and therapeutic indicators. The advent of transgenic mouse models of prostate cancer may provide a critical tool for the implementation of rational genetic based therapeutics and alternate drug design.

  View details for Web of Science ID 000089662900001

  View details for PubMedID 10762592

• Cell-cycle Dysregulation and Molecular Mechanisms of Prostate Cancer Frontiers in Bioscience Amanatullah, D. F. 2000
• The Integrin-linked Kinase Regulates the Cyclin D1 Gene through Glycogen Synthase Kinase 3 and cAMP-responsive Element-binding Protein-dependent Pathways Journal of Biological Chemistry D'Amico, M. J., Hulit, J., Amanatullah, D. F., Zafonte, B. T., Albanese, C., Bouzahzah, B., Fu, M., Augenlicht, L. H., Donehower, L. A., Takemaru, K. I., Moon, R. T., Davis, R., Lisanti, M., Shtutman, M., Zhurinsky, J., Ben-Ze'ev,, A., Troussard, A. A., Dedhar, S., Pestell, R. G. 2000; 275
• Adenosine receptor mediates motility in human melanoma cells BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS Woodhouse, E. C., Amanatullah, D. F., SCHETZ, J. A., Liotta, L. A., Stracke, M. L., Clair, T. 1998; 246 (3): 888-894

  Abstract

  Cell motility is an essential component of tumor progression and metastasis. A number of factors, both autocrine and paracrine, have been found to influence cell motility. In the present study, adenosine and adenine nucleotides directly stimulated chemotaxis of A2058 melanoma cells in the absence of exogenous factors. Three adenosine receptor agonists stimulated motility in the melanoma cells and two adenosine receptor antagonists strongly inhibited the chemotactic response to both adenosine and AMP. The chemotactic stimulation by adenosine and AMP was pertussis toxin sensitive. Otherwise unresponsive Chinese hamster ovary cells which were transfected with the adenosine A1 receptor cDNA acquired the direct, pertussis toxin sensitive, chemotactic response to adenosine, and this response was inhibited by adenosine receptor antagonists. These findings demonstrate that adenosine and adenine nucleotides are capable of stimulating chemotaxis of tumor cells mediated through an adenosine receptor, probably of the A1 subtype. The possibility of antimetastatic therapies based on inhibition of adenosine receptor activity is raised.

  View details for Web of Science ID 000074061900057

  View details for PubMedID 9618307

• Development of Metastases Cutaneous Oncology Woodhouse, E., Amanatullah, D. F., Duray, P., Liotta, L. 1998