Evaluating Modern Spacer Options and Outcomes in Revision Hip Arthroplasty.

BACKGROUND: A 2-stage revision continues to be the standard treatment for periprosthetic joint infection (PJI) in hip arthroplasty. The use of "functional" spacers may allow patients to return to daily living while optimizing their health for revision surgery. We aimed to evaluate the clinical outcomes of different spacer types regarding infection eradication, mechanical complications, and functional outcomes. METHODS: Patients who have complete Musculoskeletal Infection Society criteria for diagnosis of PJI that underwent one-stage or 2-stage revision were queried in an institutional surgical database between 2002 and 2022. Out of 286 patients, 210 met our inclusion criteria and were retrospectively reviewed for demographics, laboratory values, functional and patient-reported outcomes, and subsequent revisions. The study population had 54.3% women, a mean age of 61 years old, and a mean follow-up of 3.7 ± 3.2 years. There was no difference between age, body mass index, or Charlson Comorbidity Index scores between each cohort. Spacers were categorized as nonfunctional static, nonfunctional articulating, or functional articulating. Functional spacers were defined as those that allowed full weight bearing with no restrictions. Delphi criteria were used to define revision success, and failure was defined as a recurrent or persistent infection following definitive surgery. RESULTS: There was a significantly lower reoperation rate after a definitive implant in the functional articulating cohort (P = .003), with a trending higher infection eradication rate and a lower rate of spacer failure compared to the nonfunctional spacer cohort. At 5 years, functional articulating spacers had a 94.1% survivorship rate, nonfunctional articulating spacers had an 81.2% survival rate, and nonfunctional static spacers had a 71.4% survival rate. In the functional articulating spacer cohort, 14.6% had yet to get reimplanted, with an average follow-up time of 1.4 years. CONCLUSIONS: Within this large cohort of similar demographics, functional articulating spacers may result in better clinical outcomes and infection eradication during 2-stage revision arthroplasty for PJI.

Validation of a Classification System for Optimal Application of Debridement, Antibiotics, and Implant Retention in Prosthetic Joint Infections following Total Knee Arthroplasty: A Retrospective Review.

INTRODUCTION: Periprosthetic joint infection (PJI) remains a serious complication after total knee arthroplasty (TKA). While debridement, antibiotics, and implant retention (DAIR) are considered for acute PJI, success rates vary. This study aims to assess a new scoring system's accuracy in predicting DAIR success. METHODS: 119 TKA patients (2008-2019) diagnosed with PJI who underwent DAIR were included for analysis. Data were collected on demographics, laboratory values, and clinical outcomes. This was used for validation of the novel classification system consisting of PJI acuteness, microorganism classification, and host health for DAIR indication. Statistical analysis was carried out using SPSS programming. RESULTS: Mean follow-up was 2.5 years with an average age of 65.5 ± 9.1 years, BMI of 31.9 ± 6.2 kg/m2, and CCI of 3.04 ± 1.8. Successful infection eradication occurred in 75.6% of patients. The classification system demonstrated 61.1% sensitivity, 72.4% specificity, and 87.3% positive predictive value (PPV) when the DAIR cutoff was a score less than 6. For a cutoff of less than 8, sensitivity was 100%, specificity was 37.9%, and PPV was 83.3%. CONCLUSIONS: To date, no consensus exists on a classification system predicting DAIR success. This novel scoring system, with high PPV, shows promise. Further refinement is essential for enhanced predictive accuracy.

Effect of Femoral Head Material, Surgeon Experience, and Assembly Technique on Simulated Head-Neck Total Hip Arthroplasty Impaction Forces.

BACKGROUND: There is no standard method for assembling the femoral head onto the femoral stem during total hip arthroplasty (THA). This study aimed to measure and record dynamic 3-dimensional (3D) THA head-neck assembly loads from residents, fellows, and attending surgeons, for metal and ceramic femoral heads. METHODS: An instrumented apparatus measured dynamic 3D forces applied through the femoral stem taper in vitro for 31 surgeons (11 attendings, 14 residents, 6 fellows) using their preferred technique (ie, number of hits or mallet strikes). Outcome variables included peak axial force, peak resultant force, impulse of the resultant force, loading rate of the resultant force, and off-axis angle. They were compared between femoral head material, surgeon experience level, and the number of hits per trial. RESULTS: Average peak axial force was 6.92 ± 2.11kN for all surgeons. No significant differences were found between femoral head material. Attendings applied forces more "on-axis" as compared to both residents and fellows. Nine surgeons assembled the head with 1 hit, 3 with 2 hits, 14 with 3 hits, 2 with 4 hits, and 3 with ≥5 hits. The first hit of multihit trials was significantly lower than single-hit trials for all outcome measures except the off-axis angle. The last hit of multihit trials had a significantly lower impulse of resultant force than single-hit trials. CONCLUSION: Differences in applied 3D force-time curve dynamic characteristics were found between surgeon experience level and single and multihit trials. No significant differences were found between femoral head material.

Salvage Options for the Failed Total Knee Arthroplasty.

Total knee arthroplasty (TKA) is one of the most popular and successful procedures of the past century. However, as the number of TKAs continues to increase, the volume of revision surgeries also will increase. Although revision TKAs are often successful, adult reconstruction surgeons will likely continue to see patients with limited arthroplasty options after multiple failed revision TKAs. This raises the question of limb salvage versus transfemoral amputation as the final procedure option. It is important to review modern techniques for the patient who has undergone multiple revision TKAs with significant bone loss or chronic infection. These techniques include distal femur replacement, total femur arthroplasty, knee arthrodesis, and transfemoral amputation.

Modern Total Knee Arthroplasty Bearing Designs and the Role of the Posterior Cruciate Ligament.

The role of the posterior cruciate ligament (PCL) in total knee arthroplasty (TKA) surgery continues to be a source of debate among the adult reconstruction community. In native knee flexion, the PCL is comprised of an anterolateral and posteromedial bundle that work together to limit posterior tibial translation and allow adequate femoral rollback for deep flexion. In the arthritic knee, the PCL can often become dysfunctional and attenuated, which led to the development of posterior stabilized (PS) TKA bearing options. PS TKAs implement a cam-post construct to functionally replace a resected PCL. While PS designs may facilitate balancing knees with significant deformity, they are associated with complications such as postfracture, increased wear, and patellar clunk/crepitus. In recent years, newer designs have been popularized with greater degrees of congruency and incorporation of medial and lateral pivoting to better recreate native knee kinematics. The American Joint Registry has confirmed the recent predilection for ultra-congruent and cruciate-retaining TKA inserts over PS TKAs during the last decade. Studies have failed to identify an overall clinical superiority between the cruciate substituting and sacrificing designs. The literature has also failed to identify clinical consequences from PCL resection with modern, more conforming TKA designs. In this article, we review modern PCL sacrificing designs and discuss the impact of each on the kinematics after TKA. We also will delineate the role of the PCL in modern TKA in the hopes to better understand the recent surge in sacrificing but not substituting knee implants.

Highlights of the 2022 American Joint Replacement Registry Annual Report.

The 2022 American Joint Replacement Registry Annual Report includes data from over 2.8 million hip and knee procedures from over 1,250 institutions that encompass all 50 states and the District of Columbia. This represents a cumulative registered procedural volume growth of 14% compared to the previous year, making the American Joint Replacement Registry the largest arthroplasty registry by volume in the world.

Has Wrought Cobalt-Chromium-Molybdenum Alloy Changed for the Worse Over Time?

BACKGROUND: Total hip arthroplasty (THA) failure due to tribocorrosion of modular junctions and resulting adverse local tissue reactions to corrosion debris have seemingly increased over the past few decades. Recent studies have found that chemically-induced column damage seen on the inner head taper is enabled by banding in the alloy microstructure of wrought cobalt-chromium-molybdenum alloy femoral heads, and is associated with more material loss than other tribocorrosion processes. It is unclear if alloy banding represents a recent phenomenon. The purpose of this study was to examine THAs implanted in the 1990s, 2000s, and 2010s to determine if alloy microstructure and implant susceptibility to severe damage has increased over time. METHODS: Five hundred and forty-five modular heads were assessed for damage severity and grouped based on decade of implantation to serve as a proxy measure for manufacturing date. A subset of heads (n = 120) was then processed for metallographic analysis to visualize alloy banding. RESULTS: We found that damage score distribution was consistent over the time periods, but the incidence of column damage significantly increased between the 1990s and 2000s. Banding also increased from the 1990s to 2000s, but both column damage and banding levels appear to recover slightly in the 2010s. CONCLUSION: Banding, which provides preferential corrosion sites enabling column damage, has increased over the last 3 decades. No difference between manufacturers was seen, which may be explained by shared suppliers of bar stock material. These findings are important as banding can be avoidable, reducing the risk of severe column damage to THA modular junctions and failure due to adverse local tissue reactions.

Modern Description of Antibiotic Spacer Options for PJI in Revision Total Knee Arthroplasty: Clinical Outcomes and Infection Eradication Rates.

BACKGROUND: As the burden of periprosthetic joint infections (PJIs) increases, there is growing interest in understanding the efficacy and morbidity reduction of 2-stage revision and various antibiotic spacer options. This study aimed to expand the description and evaluation of spacers from solely their articulation status to include their ability to support full (functional) or partial weight-bearing (nonfunctional). METHODS: Between 2002 and 2021, 391 patients who had Musculoskeletal Infection Society criteria for PJI with 1-stage or 2-stage revision were included. Demographics, functional outcomes, and subsequent revision data were collected. The study population had a mean follow-up of 2.9 years (range, 0.05-13.0) with an average age of 67 years (range, 34.7-93.4). Spacer failure was defined by surgical intervention following definitive surgery, and infection eradication was defined by the Delphi criteria. Spacers were classified as nonfunctional static, nonfunctional dynamic, functional static, or functional dynamic. Two tailed t-tests were performed. RESULTS: There were no significant differences in infection eradication or mechanical outcomes across spacer types; notably, 97.3% of functional dynamic spacers achieved infection eradication. Functional spacers had a longer time to the second stage procedure and a greater number of patients who had not been reimplanted. There was no difference in reoperation rates in nonfunctional versus functional spacers. CONCLUSION: Within this cohort, infection eradication and spacer exchange rates were noninferior among spacers. Functional spacers may allow for earlier return to daily living given the weight-bearing capability when compared to nonfunctional, without sacrificing clinical outcome.

Nationwide Results of Microorganism Antigen Testing as a Component of Preoperative Synovial Fluid Analysis.

BACKGROUND: Antigen immunoassays to detect synovial fluid (SF) microorganisms have recently been made available for clinical use. The purpose of this study was to determine the sensitivity and specificity of an SF microorganism antigen immunoassay detection (MID) panel, evaluate the panel's capability to detect microorganisms in the setting of culture-negative periprosthetic joint infection (PJI), and determine diagnostic predictive values of the MID panel for PJI. METHODS: This study included 67,441 SF samples obtained from a hip or knee arthroplasty, from 2,365 institutions across the United States, submitted to 1 laboratory for diagnostic testing. All data were prospectively compiled and then were analyzed retrospectively. Preoperative SF data were used to classify each specimen by the International Consensus Meeting (2018 ICM) definition of PJI: 49,991 were not infected, 5,071 were inconclusive, and 12,379 were infected. The MID panel, including immunoassay tests to detect Staphylococcus, Candida, and Enterococcus, was evaluated to determine its diagnostic performance. RESULTS: The MID panel demonstrated a sensitivity of 94.2% for infected samples that yielded positive cultures for target microorganisms (Staphylococcus, Candida, or Enterococcus). Among infected samples yielding positive cultures for their respective microorganism, individual immunoassay test sensitivity was 93.0% for Staphylococcus, 92.3% for Candida, and 97.2% for Enterococcus. The specificity of the MID panel for samples that were not infected was 98.4%, yielding a false-positive rate of 1.6%. The MID panel detected microorganisms among 49.3% of SF culture-negative infected samples. For PJI as a diagnosis, the positive predictive value of the MID panel was 91.7% and the negative predictive value was 93.8%. Among MID-positive PJIs, 16.2% yielded a discordant cultured organism instead of that detected by the antigen test. CONCLUSIONS: SF microorganism antigen testing provides a timely adjunct method to detect microorganisms in the preoperative SF aspirate, yielding a low false-positive rate and enabling the detection of a microorganism in nearly one-half of SF culture-negative PJIs. LEVEL OF EVIDENCE: Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Interaction of surface topography and taper mismatch on head-stem modular junction contact mechanics during assembly in modern total hip replacement.

Implant failure due to fretting corrosion at the head-stem modular junction is an increasing problem in modular total hip arthroplasty. The effect of varying microgroove topography on modular junction contact mechanics has not been well characterized. The aim of this study was to employ a novel, microgrooved finite element (FEA) model of the hip taper interface and assess the role of microgroove geometry and taper mismatch angle on the modular junction mechanics during assembly. A two-dimensional, axisymmetric FEA model was created using a modern 12/14 taper design of a CoCrMo femoral head taper and Ti6Al4V stem taper. Microgrooves were modeled at the contacting interface of the tapers and varied based on height and spacing measurements obtained from a repository of measured retrievals. Additionally, taper angular mismatch between the head and stem was varied to simulate proximal- and distal-locked engagement. Forty simulations were conducted to parametrically evaluate the effects of microgroove surface topography and angular mismatch on predicted contact area, contact pressure, and equivalent plastic strain. Multiple linear regression analysis was highly significant (p < 0.001; R2 > 0.74) for all outcome variables. The regression analysis identified microgroove geometry on the head taper to have the greatest influence on modular junction contact mechanics. Additionally, there was a significant second order relationship between both peak contact pressure (p < 0.001) and plastic strain (p < 0.001) with taper mismatch angle. These modeling techniques will be used to identify the implant parameters that maximize taper interference strength via large in-silico parametric studies.

Development and internal validation of machine learning algorithms for predicting complications after primary total hip arthroplasty.

INTRODUCTION: Complications after total hip arthroplasty (THA) may result in readmission or reoperation and impose a significant cost on the healthcare system. Understanding which patients are at-risk for complications can potentially allow for targeted interventions to decrease complication rates through pursuing preoperative health optimization. The purpose of the current was to develop and internally validate machine learning (ML) algorithms capable of performing patient-specific predictions of all-cause complications within two years of primary THA. METHODS: This was a retrospective case-control study of clinical registry data from 616 primary THA patients from one large academic and two community hospitals. The primary outcome was all-cause complications at a minimum of 2-years after primary THA. Recursive feature elimination was applied to identify preoperative variables with the greatest predictive value. Five ML algorithms were developed on the training set using tenfold cross-validation and internally validated on the independent testing set of patients. Algorithms were assessed by discrimination, calibration, Brier score, and decision curve analysis to quantify performance. RESULTS: The observed complication rate was 16.6%. The stochastic gradient boosting model achieved the best performance with an AUC = 0.88, calibration intercept = 0.1, calibration slope = 1.22, and Brier score = 0.09. The most important factors for predicting complications were age, drug allergies, prior hip surgery, smoking, and opioid use. Individual patient-level explanations were provided for the algorithm predictions and incorporated into an open access digital application: https://sorg-apps.shinyapps.io/tha_complication/ CONCLUSIONS: The stochastic boosting gradient algorithm demonstrated good discriminatory capacity for identifying patients at high-risk of experiencing a postoperative complication and proof-of-concept for creating office-based applications from ML that can perform real-time prediction. However, this clinical utility of the current algorithm is unknown and definitions of complications broad. Further investigation on larger data sets and rigorous external validation is necessary prior to the assessment of clinical utility with respect to risk-stratification of patients undergoing primary THA. LEVEL OF EVIDENCE: III, therapeutic study.

A Systematic Approach to Revision Total Knee Arthroplasty.

With the recent increase in primary total knee arthroplasties and the associated rise in failures of the index operation, there has been growing demand for orthopaedic surgeons to perform revision procedures. The orthopaedic surgeon performing revision total knee arthroplasty should be knowledgeable about the various etiologies of primary total knee arthroplasty failure, the steps for proper patient evaluation, and important factors in the preoperative planning process. A systematic methodology for obtaining surgical exposure, strategies for reconstruction, fundamentals of soft-tissue closure, and postoperative care also should be reviewed.

Physician Use of Multiple Criteria to Diagnose Periprosthetic Joint Infection May Be Less Accurate Than the Use of an Individual Test.

Introduction Multiple-criterion scoring systems for periprosthetic joint infection (PJI) can be algorithmically implemented in research, diagnostically outperforming individual tests. This improved performance may be lost in the practice setting, where clinicians rarely utilize strict algorithms. The ability of physicians to interpret multiple criteria for PJI and confront the complexity of combining them into a final diagnosis has never been studied. This study assessed the diagnostic characteristics of physicians using multiple criteria to diagnose PJI and compared the physicians' diagnostic accuracy to that of individual tests. Methods A total of 12 physicians, including academic arthroplasty surgeons (N=4), community arthroplasty surgeons (N=4), and infectious disease (ID) specialists (N=4) were asked to use their routine clinical diagnostic practice to assign a diagnosis to 277 clinical vignettes using multiple preoperative laboratory criteria for PJI. The undecided rate, interobserver agreement, and accuracy of physicians were characterized relative to the 2013 Musculoskeletal Infection Society (MSIS) gold standard and compared to the accuracy of each individual laboratory test for PJI. Results Physicians interpreting multiple criteria for PJI demonstrated high undecided diagnosis rates (mean=23.5%), poor interobserver agreement (kappa range=0.49-0.63), and mean accuracy of 90.8% (range:85.8%-97.4%) compared to the 2013 MSIS gold standard. The group of academic arthroplasty surgeons had a lower rate of undecided diagnoses than community arthroplasty surgeons (16.2% vs. 29.1%; p<0.0001) or ID specialists (16.2% vs. 25.1%; p<0.0001). Academic arthroplasty surgeons also exhibited a higher interobserver agreement than community arthroplasty surgeons (kappa = 0.63 (95%CI:0.59-0.68) vs. 0.49 (95%CI:0.44-0.54)). Mean physician accuracy (90.8%) was inferior to the alpha-defensin laboratory test (96.0%;p=0.0034) and the alpha-defensin lateral-flow test (94.6%;p=0.036), comparable to synovial fluid white blood cells (SF-WBC) (93.3%;p=0.17) and synovial fluid polymorphonuclear cell % (SF-PMN%) (94.0%;p=0.11), and superior to the erythrocyte sedimentation rate (ESR) (86.2%;p<0.0001) and C-reactive protein (CRP) (84.6%;p<0.0001). Only two academic arthroplasty surgeons in this study were able to outperform every individual test for PJI by combining multiple criteria to make a diagnosis. Conclusion Although multiple-criterion scoring systems may outperform individual tests for diagnosing PJI in the research setting, it appears that the complexity of using multiple tests to diagnose PJI causes indecision and variability among physicians. Physician use of multiple preoperative criteria to diagnose PJI is less accurate than the strict algorithmic calculation of the diagnosis as achieved in research. In fact, most physicians in this study would have improved their diagnostic accuracy for PJI by simply utilizing a single good test to make the diagnosis, instead of trying to combine multiple tests into a decision. We propose that less complex diagnostic criteria should be explored for routine clinical utilization.

Laboratory-Reported Normal Value Ranges Should Not Be Used to Diagnose Periprosthetic Joint Infection.

INTRODUCTION: Clinical laboratories offer several multipurpose tests, such as the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), which are not intended to diagnose any specific disease but are used by clinicians in multiple fields. The results and laboratory interpretation (normal/abnormal) of these multipurpose tests are based on laboratory-reported normal thresholds, which vary across clinical laboratories. In 2018, the International Consensus Meeting on Musculoskeletal Infection (2018 ICM) provided a gold-standard definition to diagnose periprosthetic joint infection (PJI) which included many multipurpose laboratory tests, along with thresholds optimized to diagnose PJI. The discrepancy between laboratory-reported normal thresholds and 2018 ICM-recommended PJI-optimized test thresholds has never been studied. The purpose of this study was to assess the existing variation in laboratory-reported normal thresholds for tests commonly used to diagnose PJI and evaluate the potential diagnostic impact of using laboratory-reported normal thresholds instead of 2018 ICM-recommended PJI-optimized thresholds. METHODS: Clinical laboratories (N=85) were surveyed to determine the laboratory-reported units of measure and normal thresholds for common multipurpose tests to diagnose PJI, including the ESR, CRP, D-dimer, synovial fluid white blood cells (SF-WBC), and polymorphonuclear cell percent (SF-PMN%). The variability of units of measure and normal thresholds for each test was then assessed among the 85 included clinical laboratories. A representative dataset from patients awaiting a revision arthroplasty was used to determine the clinical significance of the existing discrepancy between laboratory-reported normal test interpretations and 2018 ICM-recommended PJI-optimized test interpretations. RESULTS: Two units of measure for the CRP and six units of measure for the D-dimer were observed, with only 59% of laboratories reporting the CRP in terms of mg/L and only 16% reporting the D-dimer in ng/ml, as needed to utilize the 2018 ICM definition of PJI. Across clinical laboratories surveyed, the mean laboratory-reported normal thresholds for the ESR (20 mm/h), CRP (7.69 mg/L), D-dimer (500 ng/mL), SF-WBC (5 cells/uL), and SF-PMN% (25%) were substantially lower than the 2018 ICM-recommended PJI-optimized thresholds of 30 mm/h, 10 mg/L, 860 ng/mL, 3,000 cells/uL, and 70%, respectively. Interpretation of test results from a representative PJI dataset using each laboratory's normal test thresholds yielded mean false-positive rates of 14% (ESR), 18% (CRP), 42% (D-dimer), 93% (SF-WBC), and 36% (SF-PMN%) versus the ICM-recommended PJI-optimized thresholds. CONCLUSION: When reporting the results for multipurpose laboratory tests, such as the ESR, CRP, D-dimer, SF-WBC, and SF-PMN%, clinical laboratories utilize laboratory-reported units of measure and normal thresholds that are not intended to diagnose PJI, and therefore may not match the 2018 ICM recommendations. Our findings reveal that laboratory-reported normal thresholds for these multipurpose tests are well below the 2018 ICM recommendations to diagnose PJI. Clinical reliance on laboratory-reported results and interpretations, instead of strict use of the 2018 ICM-recommended units and PJI-optimized thresholds, may lead to false-positive interpretation of multipurpose laboratory tests.

An Atypical Adverse Local Tissue Reaction After Ceramic-on-Ceramic Primary Total Hip Arthroplasty.

Adverse local tissue reaction is an uncommon but frequently described complication after total hip arthroplasty (THA). It is most often associated with metal-on-metal hips and less frequently with metal-on-polyethylene implants as part of a mechanically assisted crevice corrosion process. In this report, we describe a rare case of an atypical adverse local tissue reaction in a patient with a ceramic-on-ceramic THA. Abrasive backside liner wear from a prominent screw head, failure of the liner locking mechanism, and liner fragmentation secondary to component-component impingement created an atypical mass and fluid collection leading to THA failure. This case demonstrates the importance of appropriate cup-liner positioning, thorough workup of pain after THA, and the ability of ceramic debris to cause an associated, atypical adverse local tissue reaction.

A Retrospective Review of Relative Value Units in Revision Total Knee Arthroplasty: A Dichotomy Between Surgical Complexity and Reimbursement.

BACKGROUND: Revision total knee arthroplasties (TKA) are costly, time-intensive, and technically demanding procedures. There are concerns regarding the valuation of Current Procedural Terminology (CPT) codes and the assigned relative value units (RVU) as a potential disincentive to perform revision TKAs. This study evaluated the labor and time investment for each component-specific revision and assessed the disparities between procedural value billed and reimbursement. METHODS: A retrospective review of 154 primary and revision TKA cases were thoroughly vetted using operative notes and internal billing data. Revision TKAs were stratified by single femoral component, single tibial component, polyethylene liner only, all-component, and spacer placement for prosthetic infection. Operative time, RVUs billed, total charges, deductions, and reimbursements were recorded. Mann-Whitney U tests compared final reimbursement per minute and per RVU between revision and primary TKAs. RESULTS: There were 28 primary TKAs, 11 femoral component revisions, 25 tibial component revisions, 25 liner exchanges, 37 all-component revisions, and 28 spacer placements. Revisions involving the tibial component, all-components, and placement of spacers were reimbursed less dollars per minute than primary TKAs (P < .05). Controlling for RVUs, liner exchanges and all-component revisions had fewer dollars per RVU than primary TKAs (P < .05). CONCLUSION: As revision complexity increases, physicians face less reimbursement per minute and per RVU. With reductions set by CMS and private insurers, revisions may be financially unfavorable and lead to restrictions and access to care problems. Our data supports the need for reevaluating RVU allocation amongst revision procedures with potential updates to the CPT coding system.

A Retrospective Review of Reimbursement in Revision Total Hip Arthroplasty: A Disparity Between Case Complexity and RVU Compensation.

BACKGROUND: Revision total hip arthroplasties (THA) are time-consuming, expensive, and technically challenging. Today's Current Procedural Terminology (CPT) codes and relative value units (RVU) may in fact disincentivize surgeons to perform revision THAs. Our study reviewed labor and time investments for each component-specific revision THA and analyzed the gap between procedural value billed and final reimbursement. METHODS: A retrospective review of 165 primary and revision THAs were validated using operative notes and billing records. We stratified revision THAs by standard CPT coding (with modifiers) as single acetabular component, single femoral component, femoral head plus polyethylene liner (head/liner) exchange, all-components, and spacer placement for infection. Operative time, RVUs, total charges, deductions, and final reimbursement data was collected. Mann-Whitney U tests studied final reimbursement per minute vs per RVU in revision and primary THAs. RESULTS: Our cohort consisted of 27 primary THAs, 26 acetabular component revisions, 32 head/liner exchanges, 26 femoral component revisions, 27 all-component revisions, and 27 spacer placements. Compared to primary THAs, every revision subgroup except for head/liner exchanges were found to reimburse less per minute and all revision subgroups reimbursed less per RVU (P < .05). CONCLUSION: Physicians face less reimbursement per minute and per RVU for revision THAs. With cuts in reimbursement set forth by Centers for Medicare and Medicaid Services (CMS) and insurers, revisions may be financially unfavorable. This ultimately will lead to an impending access to care problem in the future. Our study supports the need to re-examine the RVU allocation amongst revision THAs and evaluate changes to the Current Procedural Terminology (CPT) coding system.