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Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_6 | Pages 39 - 39
1 Jul 2020
Mohamed N Castrodad I Etcheson J Gwam C George N Delanois R Jetty A Roadcloud E Elmallah R
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Revision total knee arthroplasty (TKA) procedures performed secondary to periprosthetic joint infection (PJI) are associated with significant morbidity and mortality. These poor outcomes may be further complicated by the development of postoperative infection requiring aggressive antibiotic treatment. However, this antibiotic overuse may suppress patients' native bacterial flora, leading to Clostridium difficile infection (CDI). With the increased demand for primary TKAs and expected rise in revision TKA due to PJI, it is important to identify factors contributing to CDI. Therefore, we aimed to study the: 1) incidence, 2) demographics, length of stay (LOS), and total costs, and 3) risk factors and mortality associated with CDI in revision TKA patients.

The National Inpatient Sample database was queried for all individuals diagnosed with PJI and who underwent revision TKA between 2009 and 2013. Patients who developed CDI during their in-patient hospital stay were identified, yielding 83,806 patients (799 with CDI) with a mean age of 65 (S.D.=11.2). Logistic regression analysis was conducted to assess the association between hospital- and patient-specific characteristics and the development of CDI.

During the study period, the overall incidence of CDI after revision TKA was 1%. These patients were significantly older (mean age 69.05 vs. 65.52 yrs), had greater LOS (median 11 vs. 5 days), had greater costs ($30,612.93 vs. 18,873.75), and had higher in-hospital mortality (3.6 vs. 0.5%, p < 0 .001 for all) compared to those without infection. Patients with CDI were more likely to be treated in urban, not-for-profit, medium or large bed-sized hospitals located in the Northeast or Midwest (p < 0 .05 for all). Patients with underlying depression (OR 4.267, p=0.007) or fluid/electrolyte disorders (OR 3.48, p=0.001) were more likely to develop infection.

Although CDI is a rare event following revision TKA, it can have detrimental consequences. Our report demonstrates that CDI is associated with longer LOS, higher costs, and greater in-hospital mortality. With increased legislative pressure to lower healthcare expenditures, it is crucial to identify means of preventing costly complications.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_5 | Pages 124 - 124
1 Mar 2017
Roche M Law T Chughtai M Elmallah R Hubbard Z Mont M
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Introduction

There is a paucity of studies analyzing the rates of revision total knee arthroplasty in diabetic patients stratified by glycated hemoglobin levels. The purpose of this study was to: 1) determine the incidence of revision TKA; 2) correlate the percent of glycated hemoglobin with incidence of revision; and 3) determine the cause of revision in diabetic patients stratified by glycated hemoglobin level.

Methods

We utilized a national private payer dataset within the PearlDiver database from 2007 to 2015 quarter 1 to determine who had diabetes and underwent TKA. There were 424,107 patients who were included in the analysis. We determined the incidence of revision TKA in the overall cohort, in addition to stratifying the incidence by glycated hemoglobin levels. To determine the effect of glycated hemoglobin levels on revision TKA rate, we performed a correlation analysis between the level of glycated hemoglobin and the incidence of revision TKA. We performed descriptive statistics of the underlying cause of revision TKA in both the overall and stratified cohorts


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_3 | Pages 105 - 105
1 Feb 2017
Bhowmik-Stoker M Martinez N Bluemke V Elmallah R Mont M Dunbar M
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Background

Total knee arthroplasty (TKA) is a routine, cost-effective treatment for end-stage arthritis. While the evidence for good-to-excellent patient-reported outcomes and objective clinical data is present, approximately 20% of patients continue to be dissatisfied with results of their surgery. Dissatisfaction is strongly correlated with unmet patient expectations, and these patients may experience a higher cost of care due to recurring office and emergency visits. Therefore, this survey asked a large group of United States (U.S) and international surgeons to prioritize areas of opportunity in primary TKA. Specifically, we compared surgeon responses regarding: 1) the top 5 areas needing improvement; which were stratified by: 2) surgeons' years of experience; and 3) surgical case volume.

Methods

A total of 418 orthopaedic surgeons were surveyed. Two hundred U.S. surgeons and 218 international surgeons participated from 7 different countries including: The United Kingdom (40), France (40), Germany (43), Italy (40), Spain (38), and Australia (17). To participate, surgeons had to be board certified, in practice for 2 years, spend 60% of their time in clinical practice, and perform a minimum of 25 joint arthroplasties per year. Surgeons were asked to choose the top 5 areas of improvement for TKA from a list of 17 attributes including clinical and functional outcomes, procedural workflow and economic variables. Surgeons were able to specify additional options if needed. Results were stratified by annual case volume (25 to 50; 51 to 100; greater than 100 cases) and years of experience (1 to 10; 11 to 20; greater than 20). Single-tail proportion tests were used to compare results between cohorts, where an alpha of 0.05 was set as significant.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_4 | Pages 145 - 145
1 Feb 2017
McCarthy T Mont M Nevelos J Alipit V Elmallah R
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INTRODUCTION

Femoral stem impingement can damage an acetabular liner, create polyethylene wear, and potentially lead to dislocation. To avoid component-to-component impingement, many surgeons aim to align acetabular cups based on the “Safe Zone” proposed by Lewinnek. However, a recent study indicates that the historical target values for cup inclination and anteversion defined by Lewinnek et al. may be useful but should not be considered a safe zone. The purpose of this study was to determine the effect of altering femoral head size on hip range-of-motion (ROM) to impingement.

METHODS

Ten healthy subjects were instrumented and asked to perform six motions commonly associated with hip dislocation, including picking up an object, squatting, and low-chair rising. Femur-to-pelvis relative motions were recorded throughout for flexion/extension, abduction/adduction, and internal/external rotation.

A previously reported custom, validated hip ROM three-dimensional simulator was utilized. The user imports implant models, and sets parameters for pelvic tilt, stem version, and specific motions as defined by the subjects. Acetabular cup orientations for abduction and anteversion combinations were chosen. The software was then used to compute minimum clearances or impingement between the components for any hip position.

Graphs for acetabular cup abduction vs. anteversion were generated using a tapered wedge stem with a 132º neck angle, a stem version of 15°, and a pelvic tilt of 0°. The only variable changed was femoral head size. Head sizes reviewed were 32mm, 36mm, and a Dual-Mobility liner with an effective head size of 42mm. All femoral head sizes can be used with a 50mm acetabular cup.