Robert L Barrack

Barnes Jewish Hospital, San Luis, Missouri, United States

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Publications (288)701.41 Total impact

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    ABSTRACT: Custom cutting guides (CCGs; sometimes called patient-specific instrumentation [PSI]) in total knee arthroplasty (TKA) use preoperative three-dimensional imaging to fabricate cutting blocks specific to a patient's native anatomy. The purposes of this study were to determine if CCGs (1) improve clinical outcomes as measured by UCLA activity, SF-12, and Oxford knee scores; and (2) coronal mechanical alignment versus standard alignment guides. This was a retrospective cohort study of patients undergoing primary TKA using the same cruciate-retaining, cemented TKA system between January 2009 and April 2012. Patients were included if they were candidates for a unilateral, cruciate-retaining TKA and met other prespecified criteria; patients were allowed to self-select either an MRI-based CCG procedure or standard TKA. Ninety-seven of 120 (80.8%) patients in the standard and 104 of 124 (83.9%, p = 0.5) in the CCG cohort with a minimum of 1-year followup were available for analysis. The first 95 patients in the standard (mean followup, 3 years; range, 1-4 years) and CCG (mean followup, 2 years; range, 1-4 years) cohorts were compared. The alignment goal for all TKAs was a hip-knee-ankle (HKA) angle of 0°. UCLA, SF-12, and Oxford knee scores were collected preoperatively and at each patient's most recent followup visit. Postoperative, rotationally controlled coronal scout CT scans were used to measure HKA alignment. Independent-sample t-tests and chi-square tests were used for comparisons with a p value ≤ 0.05 considered significant. At the most recent followup, no differences were present between the two cohorts for range of motion (114° ± 14° in CCG versus 115° ± 15° in standard, p = 0.7), UCLA (6 ± 2 in CCG versus 6 ± 2 in standard, p = 0.7), SF-12 physical (44 ± 12 in CCG versus 41 ± 12 in standard, p = 0.07), or Oxford knee scores (39 ± 9 in CCG versus 37 ± 10 in standard, p = 0.1). No differences were present for the incremental improvement in the UCLA (1 ± 4 in CCG versus 1 ± 3 in standard, p = 0.5), SF-12 physical (12 ± 20 in CCG versus 11 ± 21, p = 0.8), or Oxford knee scores (16 ± 9 in CCG versus 19 ± 10 in standard, p = 0.1) from preoperatively to postoperatively. There was no difference in the percentage of outliers for alignment (23% in standard versus 31% in CCG with HKA outside of 0° ± 3°; p = 0.2) between the two cohorts. At a mean followup of greater than 2 years, CCGs fail to demonstrate any advantages in validated knee outcome measure scores or coronal alignment as measured by CT scan versus the use of standard instrumentation in TKA. The clinical benefit of CCGs must be proven before continued implementation of this technology. Level III, retrospective controlled study.
    Clinical Orthopaedics and Related Research 02/2015; DOI:10.1007/s11999-015-4216-y · 2.88 Impact Factor
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    ABSTRACT: We hypothesized that the time period studied would have a greater impact on perioperative outcomes than the hip arthroplasty procedure performed, demonstrating concerns with studies comparing new techniques to "historical" controls. One hundred total hip arthroplasty (THA) and 100 surface replacement arthroplasty (SRA) patients performed between 2004 and 2010 ("historical" period) were matched and compared to 50 THA and 50 SRA patients performed between 2010 and 2012 ("recent" period). Time to discharge was significantly improved for both the THA and SRA groups in the recent versus historical period by 16hours (P<0.001). At both periods, THA patients were discharged earlier by 9hours versus SRAs (P<0.0001). Study time frame had a greater impact than the operative procedure on perioperative metrics. Copyright © 2015 Elsevier Inc. All rights reserved.
    The Journal of Arthroplasty 02/2015; DOI:10.1016/j.arth.2015.02.002 · 2.37 Impact Factor
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    ABSTRACT: The aims of this retrospective study were to compare the mid-term outcomes following revision total knee replacement (TKR) in 76 patients (81 knees) < 55 years of age with those of a matched group of primary TKRs based on age, BMI, gender and comorbid conditions. We report the activity levels, functional scores, rates of revision and complications. Compared with patients undergoing primary TKR, those undergoing revision TKR had less improvement in the mean Knee Society function scores (8.14 (-55 to +60) vs 23.3 points (-40 to +80), p < 0.001), a similar improvement in UCLA activity level (p = 0.52), and similar minor complication rates (16% vs 13%, p = 0.83) at a mean follow-up of 4.6 years (2 to 13.4). Further revision surgery was more common among revised TKRs (17% vs 5%, p = 0.02), with deep infection and instability being the most common reasons for failure. As many as one-third of patients aged < 55 years in the revision group had a complication or failure requiring further surgery. Young patients undergoing revision TKR should be counselled that they can expect somewhat less improvement and a higher risk of complications than occur after primary TKR.
    The Bone & Joint Journal 12/2014; 96-B(12):1657-1662. DOI:10.1302/0301-620X.96B12.34486 · 2.80 Impact Factor
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    ABSTRACT: Potential sources of alignment variability not yet investigated with the use of custom cutting guides (CCG) in total knee arthroplasty (TKA) are weight-bearing and lower extremity rotation. This study compared the preoperative planned bone resections created using an MRI-based CCG system to those from 3-dimensional, weight-bearing, full-length lower extremity images in 53 patients undergoing TKA. The angular difference between the proposed resections of the two systems was greater than 2° in 30.2% of patients for the distal femur, and 52.8% for the proximal tibia. An increased preoperative varus alignment had a slight association with an increased angular difference for the tibial resection (r=0.4). This study demonstrates weight-bearing and lower extremity rotation to be potential sources of alignment variability when using MRI-based CCGs. Copyright © 2014 Elsevier Inc. All rights reserved.
    The Journal of Arthroplasty 11/2014; 30(4). DOI:10.1016/j.arth.2014.11.009 · 2.37 Impact Factor
  • D Nam, R M Nunley, R L Barrack
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    ABSTRACT: A national, multi-centre study was designed in which a questionnaire quantifying the degree of patient satisfaction and residual symptoms in patients following total knee replacement (TKR) was administered by an independent, blinded third party survey centre. A total of 90% of patients reported satisfaction with the overall functioning of their knee, but 66% felt their knee to be 'normal', with the reported incidence of residual symptoms and functional problems ranging from 33% to 54%. Female patients and patients from low-income households had increased odds of reporting dissatisfaction. Neither the use of contemporary implant designs (gender-specific, high-flex, rotating platform) or custom cutting guides (CCG) with a neutral mechanical axis target improved patient-perceived outcomes. However, use of a CCG to perform a so-called kinematically aligned TKR showed a trend towards more patients reporting their knee to feel 'normal' when compared with a so called mechanically aligned TKR This data shows a degree of dissatisfaction and residual symptoms following TKR, and that several recent modifications in implant design and surgical technique have not improved the current situation. Cite this article: Bone Joint J 2014;96-B(11 Suppl A):96-100.
    11/2014; 96-B(11 Supple A):96-100. DOI:10.1302/0301-620X.96B11.34152
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    ABSTRACT: Recently, Levy et al questioned the effectiveness of mobile compression devices (MCDs) as the sole method of thromboprophylaxis following simultaneous bilateral total knee arthroplasty (TKA). This study's purpose was to assess if the addition of aspirin to MCDs improves venous thromboembolism (VTE) prevention following simultaneous bilateral TKA. Ninety-six patients (192 TKAs) were retrospectively reviewed: 47 patients received MCDs for 10days and aspirin for 6weeks postoperatively based on a risk stratification protocol, while 49 patients received warfarin for 4weeks postoperatively. One symptomatic VTE was noted in the warfarin cohort, while one patient in the MCD/aspirin cohort and three patients in the warfarin cohort were readmitted within 3months of surgery. In appropriately selected patients, MCDs with aspirin shows promise in VTE prevention following simultaneous bilateral TKA. Copyright © 2014 Elsevier Inc. All rights reserved.
    The Journal of Arthroplasty 10/2014; 30(3). DOI:10.1016/j.arth.2014.10.018 · 2.37 Impact Factor
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    ABSTRACT: Return to sexual activity is important to patients, but there is limited information regarding sexual function following total hip arthroplasty (THA) and total knee arthroplasty (TKA). A multicenter study of 806 THA, 542 TKA, and 181 control patients less than 60 years of age was conducted using an independent survey center to question subjects about their sexual function. Only 1.3% of THA and 1.6% of TKA patients stated they were not sexually active due to their operation. No statistically significant differences were noted in any sexual function outcome categories based on the bearing surface, femoral head size, or use of surface replacement arthroplasty in the hip cohort. Multivariate analysis revealed no difference in the percentage of patients sexually active following a THA or TKA (OR 1.19, p = 0.38). Most young active patients return to their baseline or higher level of sexual activity after hip and knee arthroplasty.
    The Journal of Arthroplasty 10/2014; 30(2). DOI:10.1016/j.arth.2014.09.029 · 2.37 Impact Factor
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    ABSTRACT: The purpose of this study was to determine the percentage of time that patients are subtherapeutic, therapeutic, and supratherapeutic based on the recommended INR for therapeutic efficacy when prescribed warfarin for chemical thromboprophylaxis following a hip or knee arthroplasty procedure. One hundred eighty-four patients receiving warfarin for 4 weeks postoperatively, dosed using a web-application accounting for patient demographics, INR levels, and concomitant medication use, were included for analysis. On average, patients with a target INR range between 1.7-2.7 were therapeutic for only 54.4% of the time (32.5% subtherapeutic, 13.0 supratherapeutic) while patients with a target INR range between 2.0 and 3.0 were therapeutic for only 45.9% of the time (39.2% subtherapeutic, 14.8% supratherapeutic) of their warfarin regimen. This study confirms that patients receiving warfarin for chemical thromboprophylaxis are within their targeted INR range for only a limited period of time during their postoperative course.
    The Journal of Arthroplasty 09/2014; 30(2). DOI:10.1016/j.arth.2014.08.032 · 2.37 Impact Factor
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    ABSTRACT: Preoperative planning for patient-specific guides (PSGs) in total knee arthroplasty (TKA) requires identification of anatomic landmarks on three-dimensional imaging studies. The aim of this study was to assess the accuracy and precision with which landmarks commonly used to determine rotational alignment in TKA can be identified on magnetic resonance imaging (MRI). Two orthopaedic surgeons and two musculoskeletal radiologists independently reviewed a sequential series of 114 MRIs of arthritic knees. The magnitude of interobserver variability was high, suggesting an inherent risk of inconsistency when these landmarks are used in PSG fabrication. Additionally, there was a high degree of physiologic variation among patients, indicating that assuming standard relationships among anatomic landmarks when placing TKA components may lead to rotational malalignment relative to each patient’s native anatomy.
    The Journal of Arthroplasty 09/2014; 30(2). DOI:10.1016/j.arth.2014.08.015 · 2.37 Impact Factor
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    ABSTRACT: Objectives Although vitamin D is recognized as an important factor in bone health, its role in osteoarticular infections is unclear. We hypothesized that low vitamin D (25-hydroxycholecalciferol) levels are associated with a lower likelihood of treatment success in osteoarticular infections. Methods This was a retrospective cohort study of patients with orthopedic infections who had a 25-hydroxycholecalciferol level drawn when their infection was diagnosed. Outcomes were determined at early (3–6 months) and late (≥6 months) follow-up after completing intravenous antibiotics. Results We included 223 patients seen during an 11-month period with osteoarticular infections and baseline 25-hydroxycholecalciferol levels. During the initial inpatient management of the infection, hypovitaminosis D was identified and treated. The mean 25-hydroxycholecalciferol level was 23 ± 14 ng/ml; 167 (75%) patients had levels <30 ng/ml. Overall, infection treatment success was 91% (159/174) at early follow-up and 88% (145/164) at late follow-up. 25-Hydroxycholecalciferol baseline levels were similar in those with and without successful clinical outcomes, both at early (25 ± 15 vs. 21 ± 9 ng/ml; p = 0.3) and late follow-up (25 ± 15 vs. 23 ± 16 ng/ml; p = 0.6). Conclusions To our knowledge this is the first report on hypovitaminosis D and its impact on outcomes of osteoarticular infections. Hypovitaminosis D was frequent in this cohort. With vitamin D repletion, there was no difference in treatment success whether patients had baseline hypovitaminosis or not.
    International Journal of Infectious Diseases 09/2014; 26. DOI:10.1016/j.ijid.2014.05.004 · 2.33 Impact Factor
  • Adam Sassoon, Denis Nam, Ryan Nunley, Robert Barrack
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    ABSTRACT: Patient-specific cutting blocks have been touted as a more efficient and reliable means of achieving neutral mechanical alignment during TKA with the proposed downstream effect of improved clinical outcomes. However, it is not clear to what degree published studies support these assumptions.
    Clinical Orthopaedics and Related Research 07/2014; 473(1). DOI:10.1007/s11999-014-3804-6 · 2.88 Impact Factor
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    ABSTRACT: Background A recent proposed modification in surgical technique in total knee arthroplasty (TKA) has been the introduction of the “kinematically aligned” TKA, in which the angle and level of the posterior joint line of the femoral component and joint line of the tibial component are aligned to those of the “normal,” pre-arthritic knee. The purpose of this study was to establish the relationship of the posterior femoral axis of the “kinematically aligned” total knee arthroplasty (TKA) to the traditional axes used to set femoral component rotation. Methods 114 consecutive, unselected patients with preoperative MRI images undergoing TKA were retrospectively reviewed. The transepicondylar axis (TEA), posterior condylar axis (PCA), antero-posterior axis (APA) of the trochlear groove, and posterior femoral axis of the kinematically aligned TKA (KAA) were templated on axial MRI images by two, independent observers. The relationships between the KAA, TEA, APA, and PCA were determined, with a negative value indicating relative internal rotation of the axis. Results On average, the KAA was 0.5° externally rotated relative to the PCA (minimum of − 3.6°, maximum of 5.8°), − 4.0° internally rotated relative to the TEA (minimum of − 10.5°, maximum of 2.3°), and − 96.4° internally rotated relative to the APA (minimum of − 104.5°, maximum of − 88.5°). Each of these relationships exhibited a wide range of potential values. Conclusions Using a kinematically aligned surgical technique internally rotates the posterior femoral axis relative to the transepicondylar axis, which significantly differs from current alignment instrument targets.
    The Knee 07/2014; 21(6). DOI:10.1016/j.knee.2014.07.025 · 1.70 Impact Factor
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    ABSTRACT: Aseptic loosening and osteolysis commonly limit the survivorship of total hip prostheses. Retention of a well-fixed acetabular component, rather than full acetabular revision, has multiple advantages, but questions have lingered regarding the clinical success and prosthetic survivorship following this procedure. We examined the impact of acetabular component position, polyethylene type, liner insertion technique, femoral head size, and simultaneous revision of the entire femoral component (as opposed to head and liner exchange) or bone-grafting on mid-term to long-term prosthetic survival following such limited revisions.METHODS: One hundred hips in 100 patients with osteolysis, polyethylene wear, or femoral component loosening underwent revision total hip arthroplasty with retention of the acetabular component. Acetabular component inclination and anteversion were measured on prerevision radiographs and were categorized according to predetermined positional safe zones (inclination of 35° to 55° and anteversion of 5° to 25°). Operative reports were reviewed for femoral head size, polyethylene liner type (conventional or highly cross-linked), liner insertion technique (use of the existing locking mechanism or cementation), whether the patient had revision of the entire femoral component, and use of bone graft. Outcomes of interest included the Harris hip score, University of California at Los Angeles (UCLA) activity score, episodes of instability, and need for repeat revision.RESULTS: At an average of 6.6 years (range, two to fourteen years) postoperatively, the Harris hip and UCLA activity scores were both significantly improved compared with the preoperative scores (p < 0.0001 and p < 0.01, respectively). Overall, the failure rate was 13%. In addition, 6% of the patients had postoperative instability. Hips in which the acetabular component was outside of the safe zone for inclination had a higher rate of failure (p = 0.048). Use of conventional, rather than highly cross-linked, polyethylene at the time of revision was also associated with an increased rate of repeat revision (p = 0.025).CONCLUSIONS: Revision total hip arthroplasty with retention of the acetabular component is associated with good outcomes in hips with an appropriately positioned, well-fixed acetabular component. Acetabular components outside the safe zone for inclination were at a higher risk for failure, as was use of conventional polyethylene.LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
    The Journal of Bone and Joint Surgery 06/2014; 96(12):1015-1020. DOI:10.2106/JBJS.L.01177 · 4.31 Impact Factor
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    ABSTRACT: Although the volume of total knee arthroplasties (TKAs) performed in the United States continues to increase, recent reports have shown the percentage of patients who remain "unsatisfied" is as high as 15% to 30%. Recently, several newer implant designs have been developed to potentially improve patient outcomes.
    Clinical Orthopaedics and Related Research 06/2014; DOI:10.1007/s11999-014-3713-8 · 2.88 Impact Factor
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    ABSTRACT: With more than 650,000 knee arthroscopies and 175,000 anterior cruciate ligament reconstructions performed annually in the United States, patients presenting for total knee arthroplasty are increasingly likely to have had previous knee surgery. The purpose of this study was to assess the prevalence of previous knee surgery in patients undergoing total knee arthroplasty and to test the hypothesis that patients with previous knee surgery undergo total knee arthroplasty at a younger age.
    The Journal of Bone and Joint Surgery 05/2014; 96(10):801-5. DOI:10.2106/JBJS.M.00105 · 4.31 Impact Factor
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    ABSTRACT: Haematomas, drainage, and other non-infectious wound complications following total knee replacement (TKR) have been associated with long-term sequelae, in particular, deep infection. However, the impact of these wound complications on clinical outcome is unknown. This study compares results in 15 patients re-admitted for wound complications within 90 days of TKR to 30 matched patients who underwent uncomplicated total knee replacements. Patients with wound complications had a mean age of 66 years (49 to 83) and mean body mass index (BMI) of 37 (21 to 54), both similar to that of patients without complications (mean age 65 years and mean BMI 35). Those with complications had lower mean Knee Society function scores (46 (0 to 100 vs 66 (20 to 100), p = 0.047) and a higher incidence of mild or greater pain (73% vs 33%, p = 0.01) after two years compared with the non re-admitted group. Expectations in patients with wound complications following TKR should be tempered, even in those who do not develop an infection. Cite this article: Bone Joint J 2014;96-B:619-21.
    05/2014; 96-B(5):619-621. DOI:10.1302/0301-620X.96B5.33479
  • Denis Nam, Robert L Barrack, Hollis G Potter
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    ABSTRACT: Adverse tissue reactions are known to occur after total hip arthroplasty using both conventional and metal-on-metal (MoM) bearings and after MoM hip resurfacing arthroplasty (SRA). A variety of imaging tools, including ultrasound (US), CT, and MRI, have been used to diagnose problems associated with wear after MoM hip arthroplasty and corrosion at the head-trunnion junction; however, the relative advantages and disadvantages of each remain a source of controversy. The purposes of this review were to evaluate the advantages and disadvantages of (1) US; (2) CT; and (3) MRI as diagnostic tools in the assessment of wear-related corrosion problems after hip arthroplasty. A systematic literature review was performed through Medline, EMBASE, Scopus CINAHL, and the Cochrane Library without time restriction using search terms related to THA, SRA, US, CT, MRI, adverse tissue reactions, and corrosion. Inclusion criteria were Level I through IV studies in the English language, whereas expert opinions and case reports were excluded. The quality of included studies was judged by their level of evidence, method of intervention allocation, outcome assessments, and followup of patients. Four hundred ninety unique results were returned and 40 articles were reviewed. The prevalence of adverse local tissue reactions in both asymptomatic and symptomatic patients varies based on the method of evaluation (US, CT, MRI) and imaging protocols. US is accessible and relatively inexpensive, yet has not been used to report synovial thicknesses in the setting of wear-related corrosion. CT scans are highly sensitive and provide information regarding component positioning but are limited in providing enhanced soft tissue contrast and require ionizing radiation. MRI has shown promise in predicting both the presence and severity of adverse local tissue reactions but is more expensive. All three imaging modalities have a role in the assessment of adverse local tissue reactions and tribocorrosion after total hip arthroplasty. Although US may serve as a screening technique for the detection of larger periprosthetic collections, only MRI has been shown to predict the severity of tissue destruction found at revision and correlate to the degree of tissue necrosis at histologic evaluation.
    Clinical Orthopaedics and Related Research 03/2014; 472(12). DOI:10.1007/s11999-014-3579-9 · 2.88 Impact Factor
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    ABSTRACT: Venous thromboembolic events, either deep venous thrombosis or pulmonary embolism, are important complications in patients undergoing knee or hip arthroplasty. The purpose of this study was to evaluate the effectiveness of a mobile compression device (ActiveCare+S.F.T.) with or without aspirin compared with current pharmacological protocols for prophylaxis against venous thromboembolism in patients undergoing elective primary unilateral arthroplasty of a lower-extremity joint. A multicenter registry was established to capture the rate of symptomatic venous thromboembolic events following primary knee arthroplasty (1551 patients) or hip arthroplasty (1509 patients) from ten sites. All patients were eighteen years of age or older with no known history of venous thromboembolism, coagulation disorder, or solid tumor. Use of the compression device began perioperatively and continued for a minimum of ten days. Patients with symptoms of deep venous thrombosis or pulmonary embolism underwent duplex ultrasonography and/or spiral computed tomography. All patients were evaluated at three months postoperatively to document any evidence of deep venous thrombosis or pulmonary embolism. Of 3060 patients, twenty-eight (0.92%) had venous thromboembolism (twenty distal deep venous thrombi, three proximal deep venous thrombi, and five pulmonary emboli). One death occurred, with no autopsy performed. Symptomatic venous thromboembolic rates observed in patients who had an arthroplasty of a lower-extremity joint using the mobile compression device were noninferior (not worse than), at a margin of 1.0%, to the rates reported for pharmacological prophylaxis, including warfarin, enoxaparin, rivaroxaban, and dabigatran, except in the knee arthroplasty group, in which the mobile compression device fell short of the rate reported for rivaroxaban by 0.06%. Use of the mobile compression device with or without aspirin for patients undergoing arthroplasty of a lower-extremity joint provides a noninferior risk for the development of venous thromboembolism compared with current pharmacological protocols. Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence. PEER REVIEW This article was reviewed by the Editor-in-Chief and one Deputy Editor, and it underwent blinded review by two or more outside experts. It was also reviewed by an expert in methodology and statistics. The Deputy Editor reviewed each revision of the article, and it underwent a final review by the Editor-in-Chief prior to publication. Final corrections and clarifications occurred during one or more exchanges between the author(s) and copyeditors.
    The Journal of Bone and Joint Surgery 02/2014; 96(3):177-83. DOI:10.2106/JBJS.L.01031 · 4.31 Impact Factor
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  • R L Barrack
    01/2014; 96(1):3-4. DOI:10.1302/0301-620X.96B1.33459

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7k Citations
701.41 Total Impact Points

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Institutions

  • 2006–2015
    • Barnes Jewish Hospital
      San Luis, Missouri, United States
  • 2004–2014
    • Washington University in St. Louis
      • Department of Orthopaedic Surgery
      San Luis, Missouri, United States
  • 2009–2011
    • Johns Hopkins University
      • Department of Orthopaedic Surgery
      Baltimore, MD, United States
    • Rothman Institute
      Philadelphia, Pennsylvania, United States
    • Rush University Medical Center
      • Department of Orthopaedic Surgery
      Chicago, IL, United States
  • 2008–2009
    • Thomas Jefferson University
      Filadelfia, Pennsylvania, United States
    • Thomas Jefferson University Hospitals
      Philadelphia, Pennsylvania, United States
  • 2007
    • Albert Einstein College of Medicine
      New York, New York, United States
  • 1997–2004
    • Louisiana State University Health Sciences Center New Orleans
      • Department of Orthopaedic Surgery
      Shreveport, LA, United States
  • 1983–2003
    • Tulane University
      • Department of Orthopaedics
      New Orleans, Louisiana, United States
  • 2001
    • University of Miami
      كورال غيبلز، فلوريدا, Florida, United States
  • 2000
    • The University of Western Ontario
      • Division of Orthopaedic Surgery
      London, Ontario, Canada
    • Anderson Orthopaedic Clinic
      Alexandria, Virginia, United States
  • 1995
    • Naval Medical Research Center
      Silver Spring, Maryland, United States
  • 1994
    • Harvard Medical School
      • Department of Orthopaedic Surgery
      Boston, Massachusetts, United States
  • 1992
    • Massachusetts General Hospital
      • Department of Orthopaedic Surgery
      Boston, MA, United States
  • 1991
    • Naval Hospital Bremerton
      Бремертон, Washington, United States