BACKGROUND:The Centers for Medicare & Medicaid Services is requiring patient-reported outcome measures (PROMs) to demonstrate the value of total joint arthroplasty (TJA). While effective PROM utilization offers major benefits, capture rates and outcomes may vary across practice settings. This study aimed to (1) compare PROMs capture rates between ambulatory surgery centers (ASCs) and hospitals and (2) evaluate relationships between surgical setting, PROM capture rates, and clinical outcomes. METHODS:Using a large national database, we conducted a retrospective cohort study of patients who underwent primary TJA between January 2020 and September 2023. The PROM capture was defined as AJRR submission of linked baseline and 1-year PROMs for four validated instruments and then compared in patients who underwent surgery at an ASC versus a hospital setting as the primary study outcome. Analyses of factors predicting PROM capture, mean score, and the likelihood of achieving minimum clinically important difference (MCID) for at least one PROM were performed using clustered logistic regression with inverse probability weighting. Statistical analyses were conducted with significance set at P < 0.05. Among 1,264,863 outpatient primary TJAs, 70,677 had linked baseline and 1-year PROMS. RESULTS:Capture rates were higher in ASCs (30.6 to 56%) than hospitals (28.6 to 34%) for all instruments (P < 0.001). However, there was no difference in achievement of MCID between settings. Institutional characteristics, including smaller size, major teaching status, and location in Southern/Western regions, predicted lower PROM capture rates. CONCLUSIONS:Our findings suggest the surgical setting influences submission patterns to AJRR, which may reflect the PROMs capture rate, but did not correlate with patients achieving MCID on studied outcome measures. Efforts to improve both collection and submission workflows of PROMs are essential for compliance and quality improvement for ASCs, hospitals, and stakeholders to ensure compliance and optimize patient care. LEVEL OF EVIDENCE:Therapeutic level III.

BACKGROUND:Although it is well established that the type of organism can be a risk factor for failure in patients with periprosthetic joint infection (PJI), no study to date has examined the impact of the number of positive cultures on treatment outcomes in patients undergoing 2-stage exchange. The purpose of this multicenter study was to determine the prognostic utility of multiple positive cultures at resection as a predictor of failure following reimplantation. METHODS:This retrospective multicenter study identified 437 patients with chronic knee PJI who had undergone 2-stage exchange arthroplasty with a minimum of 1 year of follow-up following reimplantation. PJI was defined with use of the 2013 Musculoskeletal Infection Society (MSIS) criteria. Patients with culture-negative PJI were excluded (n = 138). Treatment failure was defined as either any reoperation for infection or PJI-related mortality. Multivariable regression controlling for risk factors for failure after a 2-stage arthroplasty was performed to determine whether ≥2 positive intraoperative cultures at resection can predict outcomes following reimplantation when compared with a single positive culture. RESULTS:Two hundred and ninety-nine patients were included. At a mean follow-up of 6.2 ± 2.6 years, 48 patients (16.1%) experienced failure. Patients who had a failure were more likely to have had a longer interstage interval (p = 0.038) and were also more likely to have had ≥2 positive cultures at the time of resection arthroplasty (95.8% versus 75.3%; p = 0.001). On regression analysis, ≥2 positive cultures at resection was the only variable that was identified as a risk factor for failure following reimplantation in both the univariate (odds ratio [OR], 7.55 [95% CI, 2.24 to 47.0]; p = 0.006) and multivariable models (OR, 8.12 [95% CI, 2.31 to 51.9]; p = 0.005). CONCLUSIONS:This is the first study to examine the impact of the number of positive cultures on outcomes in patients with PJI. We found that the presence of ≥2 positive cultures at resection was an indicator of a poor prognosis and resulted in a greater than eightfold increase in the risk of treatment failure in patients undergoing a 2-stage exchange. LEVEL OF EVIDENCE:Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

While two-stage exchange arthroplasty is the gold standard for treating periprosthetic joint infections (PJIs), it results in a prolonged treatment period with the potential for complications and non-planned additional procedures, limited joint function during the interstage period, and emotional stress for patients. The primary objective of this systematic literature review was to evaluate outcomes associated with two-stage exchange arthroplasty for treating total hip arthroplasty (THA) and total knee arthroplasty (TKA) PJIs. This literature review analyzed U.S. data on the timing and health consequences associated with the interstage period and outcomes following reimplantation in patients undergoing two-stage exchange arthroplasty. A search of U.S. studies published between January 2014 and January 2024 was conducted using PubMed and Embase databases. Sixty-five studies reporting data on 26,354 patients undergoing two-stage exchange arthroplasty were included. There were 29.0

Introduction: The current standard for treating chronic periprosthetic joint infection (PJI) in North America, a two-stage exchange arthroplasty, has success rates of 65–90% but involves prolonged interstage periods, increased morbidity, and a high 5-years mortality rate of up to 25%. These limitations have driven research into alternative approaches, such as intra-articular antibiotic (IAA) irrigation, which uses a specialized titanium spacer for localized antibiotic delivery over a 7-day period. Case Report: A 53-year-old male with chronic PJI of the left knee underwent a novel rapid two-stage exchange arthroplasty using an IAA irrigation system. The first stage involved implant removal and placement of a specialized antibiotic delivery IAA device. During the 7-day interstage period, high-concentration local antibiotics (tobramycin and vancomycin) were administered. The second stage, performed 1 week later, included reimplantation with a total stabilized revision knee system. At 1-year post-surgery, the patient demonstrated excellent functional recovery, pain-free mobility, and no signs of recurrent infection. Conclusion: This case illustrates the potential of IAA in managing chronic PJI, offering rapid reimplantation and effective infection control. While promising, larger studies are needed to establish long-term efficacy and cost-effectiveness of this innovative approach. Keywords: Chronic, periprosthetic joint infection, intra-articular antibiotic, two stage, revision, knee.

BACKGROUND:The number of hip fractures in the United States continues to increase each year. Current guidelines recommend cemented femoral fixation when performing hemiarthroplasty (HA) and total hip arthroplasty (THA). Yet, more than half of femoral neck fractures in older patients are treated with cementless femoral fixation in the United States. This study examined the costs and quality-adjusted life years of cemented and cementless femoral fixation for HA and THA procedures at the population level in the United States using data from the American Joint Replacement Registry. METHODS:A Markov model was created for 11,339 Medicare patients aged 65 to 74, 75 to 84, and 85-plus years in the American Joint Replacement Registry. We simulated the expected impact on costs and health outcomes over five years if all patients received the same femoral fixation method for both HA and THA based on age. Revision, dislocation, and mortality rates, costing data, and health utilities from registry data and published literature were used to populate the model. We simulated outcome uncertainty with probabilistic sensitivity analysis. RESULTS:By switching entirely to cemented fixation, Medicare can achieve annual cost savings for these patients of $5.0 million (95% uncertainty interval [UI]: -$0.6 to $8.0 million) and 1,356 (95% UI: -618 to 3,362) quality-adjusted life years. Cost-effectiveness was observed in 92% of simulations. Extrapolated over the annual incidence of hip fractures treated with arthroplasty in the US Medicare population, this could equate to $126.6 million (95% UI: -$15.0 to $201.2 million) in annual cost savings. CONCLUSIONS:Cementless fixation remains the dominant mode of fixation for hip fractures in the United States. This cost-effectiveness study suggests potential cost savings and improved quality of life from switching to cemented femoral fixation for femoral neck fractures for both HA and THA, primarily due to lower postoperative complication rates.

Background Computer-assisted navigation and/or the use of robotics at the time of the primary total knee arthroplasty (TKA) have been shown to improve implant position, minimize alignment outliers, and possibly improve patient outcomes compared to conventional instrumentation. The purpose of this study was to use the linked Medicare dataset from the American Joint Replacement Registry to compare the midterm (5-year) outcomes of navigated TKA and robotic TKA to those of conventional TKA. Methods All primary TKA procedures submitted to the American Joint Replacement Registry between January 2017 and December 2022 among patients aged 65 years and older were included in the analysis. The data were stratified into patients who underwent navigated TKA, robotic TKA, or conventional TKA at the time of their index procedure. The all-cause revision rate, mechanical loosening rate, and the other mechanical complication rate were determined at five years postoperatively. The survival model was adjusted for age, sex, fixation type, and year. Results At five years postoperatively, the survival model found computer navigation use to not be significant in TKA all-cause revision (P = 0.32) or mechanical loosening (P = 0.91), but was significant for other mechanical complications (P = 0.004). Robotic use was not found to be significant in TKA all-cause revision (P = 0.75), mechanical loosening (P = 0.42), or other mechanical complications (P = 0.46). Conclusions Navigation and/or the use of robotics at the time of primary TKA did not demonstrate a decrease in the need for revision at five years follow-up among Medicare beneficiaries. Although this study was unable to assess other important clinical outcomes following TKA with advanced technology, the purported benefits of using this technology to improve component survival are not supported.

Background: Periprosthetic tibial fractures around a total knee replacement (TKR) remain challenging to manage, with little published information for guidance. The purpose of this study was to review the types, management techniques, and outcomes of periprosthetic tibial fractures in the largest series to date. Methods: We identified 300 periprosthetic tibial fractures (285 patients) around a TKR (43% in primary TKRs and 57% in revision TKRs) sustained between 1996 and 2020. Fractures were classified according to Felix et al. as Type I (tibial plateau), Type II (adjacent to stem), Type III (distal to stem), or Type IV (tibial tubercle), with subtypes A (well-fixed component), B (loose component), and C (intraoperative fracture). Of the fractures in this study, 53% were Type I, 24% were Type II, 16% were Type III, and 8% were Type IV. A total of 46% of fractures occurred intraoperatively, and 54% of fractures occurred postoperatively (61% subtype A, 39% subtype B). The mean patient age at fracture was 67 years, and 64% of patients were female. The mean follow-up was 6 years. Results: The intraoperative fracture incidence was 1.40% in revision TKRs and 0.10% in primary TKRs. Among intraoperative fractures, the 2-year survivorship free from tibial component revision was highest in Type I (100%) and lowest in Type IV (67%) (p < 0.001). For postoperative fractures, the 2-year survivorship free from any reoperation was 29% and the 2-year survivorship free from tibial component revision was 51%. Type-I postoperative fractures had the lowest 2-year survivorship free from tibial component revision (10%), whereas Type-III fractures had the highest survivorship (88%) (p < 0.001). Conclusions: Intraoperative periprosthetic fracture of the tibia was fourteenfold more likely in revision TKRs compared with primary TKRs. Among all intraoperative fractures, Type-I fractures were well-tolerated, with 100% survivorship free from tibial component revision at 2 years. Conversely, Type-I postoperative fractures had only 10% survivorship at 2 years. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:The purpose of this study was to identify genetic mutations in exome sequences of patients who had a history of pulmonary embolism (PE) after total joint arthroplasty (TJA). METHODS:From June 2017 to August 2021, 21 patients who had a history of TJA and subsequent postoperative PE were enrolled in three academic institutions for whole-exome sequencing. Their average age was 64 years (range, 46 to 81), and 15 (71.4%) were women. The average time to PE was 1.7 months (range, zero to 8.8). There were five patients who reported a prior history of thromboembolism, and one had a history of Factor V Leiden mutation. Genomic DNA was extracted from individual frozen blood samples, and fragmented DNA was then converted to an adapter-ligated whole-genome library. Libraries from individual patients were pooled, underwent sequencing, and were compared to population-wide data through the National Center for Biotechnology Information Library, ClinVar database, which archives and aggregates information regarding the relationships between genomic variation and health conditions. Within ClinVar, the range of mutation allele frequency in genes with established roles in coagulation in the general population is reported to be 0.001 to 1.52%. RESULTS:Mutations in genes with established roles in coagulation occurred at higher rates compared to population baselines identified in the ClinVar database. In our cohort, whole-exome sequencing identified at least one mutation of the 30 genes investigated with established roles in coagulation in 13 patients (61.9%). At least one mutation in 10 genes related to the coagulation cascade, platelet function, or blood type was identified. CONCLUSIONS:Our results suggest that genetic mutations in exome sequences are highly prevalent among patients who experience postoperative PE after TJA. These findings should serve as preliminary data to support further investigation of potential genetic risk factors on whole-exome sequencing to allow for preoperative risk stratification by TJA surgeons.

BACKGROUND:Orthopaedic surgeons routinely delay surgical management of femoral neck fractures in patients taking direct oral anticoagulants (DOACs) to decrease perioperative bleeding and associated complications. However, this practice contradicts the principles of hip fracture management, as early surgery is associated with morbidity and mortality benefits. The purpose of this study was to quantify the association of DOAC use and perioperative outcomes in patients who underwent hemiarthroplasty (HA) or total hip arthroplasty (THA) for femoral neck fractures. We hypothesized that early surgical intervention on a patient taking a DOAC medication would not lead to worse perioperative outcomes. METHODS:A retrospective cohort study was conducted on 2,833 patients who underwent primary THA or HA for femoral neck fractures between December 31, 2017, and January 29, 2024, across our hospital system. The patients taking a DOAC were divided into 3 groups based on the time since the last DOAC intake: 1 day, 2 days, and ≥3 days. Propensity matching was performed 1:1, accounting for age, sex, Elixhauser Comorbidity Index, preoperative chronic kidney disease stage, preoperative hemoglobin, body mass index, and hospital type. Subanalyses utilizing linear and conditional logistic regression models were performed to assess differences in outcomes between the groups that had a DOAC withheld and the control groups. RESULTS:The mean age of all patients was 81 ± 10 years, 1,805 patients (64%) were women, and 207 patients (7%) were taking a DOAC prior to surgery. Despite comparable preoperative and postoperative hemoglobin levels between the groups that had a DOAC withheld and the control groups (all p > 0.05), the patients who had a DOAC withheld for 1 day were more likely to receive a postoperative blood transfusion (23.1% compared with 0%; p = 0.002). This difference in transfusion rate was not observed in other cohorts. There were no differences in medical complications, reoperation, discharge disposition, or mortality between the groups that had a DOAC withheld and the matched controls at any time point. CONCLUSIONS:Delaying surgical management due to DOAC medications may be unnecessary in patients undergoing arthroplasty for femoral neck fractures. Consideration should be given to adjusting transfusion triggers to reduce unwarranted blood transfusions in patients taking a DOAC. LEVEL OF EVIDENCE:Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Aims:Periprosthetic joint infection (PJI) is a devastating complication of arthroplasty, with substantial morbidity, mortality, and healthcare costs. Despite advances in diagnosis and treatment, inconsistencies in outcome reporting have hindered evidence synthesis, limiting progress in understanding and management. This study aimed to develop a core outcome set (COS) for PJI to standardize outcome reporting in the literature. Methods:A two-stage modified Delphi process was conducted to establish consensus across a range of domains. Stage 1 involved the identification of core outcomes in PJI research by an international expert panel. A patient group was also consulted to ensure that the domains were relevant to patient priorities. Stage 2 included a broader group of 55 stakeholders in an online consensus process to finalize the COS. Quantitative and qualitative data were collated to redefine the outcomes throughout the Delphi process. Results:Following the modified two-stage Delphi process, a high level of consensus was achieved for all outcomes. The final COS included 23 outcomes across the following four domains: patient demographics and baseline characteristics; infection characteristics; surgical and treatment details; and outcomes and follow-up. Conclusion:The developed COS provides a standardized framework for reporting outcomes in PJI research. By addressing variability and inconsistency in the literature, this COS aims to enhance comparability across studies, support robust evidence synthesis, and ultimately guide clinical decision-making.

Background Debridement, antibiotics, and implant retention (DAIR) is used to manage acute periprosthetic joint infections (PJIs) after total joint arthroplasty (TJA). Given the uncertain success of single or multiple DAIR attempts and possible long-term deleterious effects this treatment can create when trying to treat persistent infection, it is important to understand the frequency with which surgeons in the United States are attempting multiple debridements for PJI and whether those procedures are achieving the desired goal. Question/purposes In the context of the American Joint Replacement Registry (AJRR), we asked: (1) What proportion of patients who undergo DAIR have only one DAIR, and what percentage of those patients have more than one? (2) Of the patients who undergo one or more DAIR procedures, what is the proportion who progress to additional surgical procedures? (3) What is the cumulative incidence of medical or surgical endpoints related to infection on the affected leg (other than additional DAIR procedures)? Methods DAIR procedures to treat PJI, defined by ICD-9/10 and CPT (Current Procedural Technology) codes, reported to the AJRR from 2012 to 2020 were merged with Centers for Medicare and Medicaid Services (CMS) data from 2012 to 2020 to determine the incidence of patients aged 65 and older who underwent additional PJI-related procedures on the same joint. Linking to CMS ensures no loss to follow-up or patient migration to a non-AJRR site. As of 2021, the AJRR captures roughly 35% of all arthroplasty procedures performed in the United States. Of the total 2.2 million procedures in the AJRR, only 0.2% of the procedures were eligible based on our inclusion criteria. Additionally, 61% of the total population is Medicare eligible, and thus, these patients are linked to CMS. Of the 5029 DAIR attempts after a TKA, 46% (2318) were performed in female patients. Similarly, there were a total of 798 DAIR attempts after a THA, and 50% (398) were performed in female patients. For the purposes of decreasing confounding factors, bilateral THAs and TKAs were excluded from the study population. When querying for eligible procedures from 2012 to 2020, the patient population was limited to those 65 years and older, and a subsequent reoperation for infection had to be reported after a primary TJA. This limited the patient population as most infections reported to AJRR resulted in a revision, and we were searching for DAIRs. Although 5827 TJAs were identified as a primary TJA with a subsequent infectious event, more than 65% (3788) of that population did not have a reported event. The following conditions were queried as secondary outcomes after the first DAIR: sepsis, cellulitis, postoperative infection, endocarditis, amputation, knee fusion, resection, drainage, arthrotomy, and debridement. To answer our first and second study questions, we used frequency testing from the available AJRR data. Because of competing risks and issues with incomplete data, we used the cumulative incidence function to evaluate the outcomes specific to study question 3. Results Of the patients who underwent DAIR, 93% (5406 of 5827) had one DAIR and 8% (421 of 5827) had more than one. Among the DAIR population, at least 35% of TKAs and 38% of THAs were identified as having experienced an additional PJI-related event (an additional surgical procedure on the same joint, sustained an infectious endpoint in the linked CMS-AJRR dataset, or they had died). The cumulative incidence of developing a further medical or surgical condition related to the joint that had the initial DAIR were as follows: 48% (95% CI 42% to 54%) at 8 years after a DAIR following a TKA and 42% (95% CI 37% to 46%) at 4 years after a DAIR following a THA. The timepoints for TKA and THA are different because there are more longitudinal procedure data available for TKAs regarding DAIR procedures than for THAs. Conclusion In this study, we used data from the AJRR to assess the incidences of single and multiple DAIR attempts and additional surgical- and infection-related sequalae. Continued investigation is required to determine the fate of infected joints that undergo DAIR with regard to ultimate patient outcome. Future cross-sectional studies using large datasets are necessary to assess functional outcomes and determine the risk of persistent infection after DAIR more precisely. Level of Evidence Level III, therapeutic study.

In the United States, the occurrence of obesity is estimated to be approximately 41.9% and is projected to continue to rise [ [1] Control CDCAdult Obesity Facts. Centers for Disease Control, Atlanta, GA2022 Google Scholar ]. As the condition has become more prevalent, so has the attention to finding treatments to combat it, both due to the rising medical consequences for patients and also because of the economic costs to our health care system. As of 2019, the estimated annual medical cost of obesity was $173 billion, with the average cost of care for these patients being approximately $1,861 more than the nonobese [ [1] Control CDCAdult Obesity Facts. Centers for Disease Control, Atlanta, GA2022 Google Scholar ]. This trend is predicted to continue, with the best estimates suggesting that almost 50% of the US population will be obese by 2030 and 25% will have morbid obesity [ [2] Ward Z.J. Bleich S.N. Cradock A.L. Barrett J.L. Giles C.M. Flax C. et al. Projected U.S. State-level prevalence of adult obesity and severe obesity. N Engl J Med. 2019; 381: 2440-2450 Crossref PubMed Scopus (916) Google Scholar ]. Furthermore, obesity is commonly associated with metabolic syndrome, including type 2 diabetes and prediabetes. Often, glucose control is resistant to traditional medications, and nearly 30% of patients who have diabetes have hemoglobin A1c levels above 8%, a relative contraindication to arthroplasty surgery [ [3] Liu L. Wang F. Gracely E.J. Moore K. Melly S. Zhang F. et al. Burden of uncontrolled hyperglycemia and its association with patients characteristics and socioeconomic status in Philadelphia, USA. Health Equity. 2020; 4: 525-532 Crossref Scopus (1) Google Scholar ].

BACKGROUND:In collaboration with the Orthopedic Data Evaluation Panel (ODEP), the American Joint Replacement Registry (AJRR) investigated the consistency of hip and knee arthroplasty survivorship results compared to the UK National Joint Registry (NJR). METHODS:A total of three primary knee devices and three primary hip devices were selected by AJRR and ODEP with known variation in performance. Implant manufacturers independently produced Kaplan Meier survivorship based on NJR data and submitted to ODEP for comparison. The AJRR mirrored the methodology, and results from both sources were stratified into three cohorts (all-age, < 65, and ≥ 65 years). RESULTS:There were 42,671 AJRR and 60,439 NJR primary knee cases and 70,169 AJRR and 422,657 NJR primary total hip arthroplasty cases. For TKA, performance between the AJRR and NJR were consistent, showing similar trends for comparatively high and low performing devices. Both PS and CR devices showed statistical agreement in survivorship for all 3 cohorts. Unicompartmental comparison also showed statistical agreement for the Medicare cohort. The all-age and < 65-year-old cohorts showed similar trends and reached statistical agreement through 7 and 6 years. For total hip arthroplasty, performance between the AJRR and NJR were consistent, showing similar trends for comparatively high and low performing devices; 0.18% average difference in survivorship at final follow-up (8 years). One femoral device did not reach statistical agreement but showed only 0.61% difference in survivorship. The remaining acetabular and femoral devices reached statistical agreement in all-ages and through 7 and 8 years in the ≥ 65-year-old cohort. CONCLUSIONS:AJRR and NJR performance trends and survivorship were similar across hip and knee arthroplasty with greatest consistency in the all-age and ≥ 65 cohorts. This focused comparison of survivorship showed encouraging results for reliability of patient outcomes in AJRR compared to the world's largest joint arthroplasty registry which has strong implications for global improvement in patient safety.

On a recent humanitarian trip to San Pedro Sula, Honduras, our Operation Walk team leaders were introduced to a local orthopaedic surgeon. While he expressed interest in our global surgery efforts, it was later divulged to us that he found the brigade unnecessary, that each arthroplasty done by the foreign missionaries takes away from his surgical opportunities. His concerns are not unfounded as evidenced by the abundance of literature regarding the ethics of global surgery/global health. Despite the humanitarian aid worker's (HAW) best intentions, unfortunately, there are often unintended consequences as local providers may be devalued, there may be a lack of continuity of care, and a dependence of the local community on the HAW can be created.

BACKGROUND:In recent years, there has been an increased utilization of dual-mobility (DM) implants in primary total hip arthroplasty (THA) to mitigate the risk of postoperative hip instability. This study aimed to present mid-term outcomes of DM bearings in primary THA using data from the American Joint Replacement Registry. METHODS:Screening was conducted on patients aged ≥ 65 years who underwent primary THA between 2012 and 2018. Patients were categorized into three groups: (1) DM articulation, (2) ≤ 32-mm femoral head, and (3) ≥ 36-mm femoral head. Multivariable statistical modeling was employed to analyze patient and hospital characteristics, minimizing potential confounding variables and identifying independent associations with revision. Cox proportional hazards regression analyses were used to assess all-cause revision and revision specifically for instability. A total of 207,526 primary THAs were identified. Among them, 13,896 (6.7%) utilized DM articulation, 60,358 (29.1%) had a femoral head size of ≤ 32 mm, and 133,272 (64.2%) had a femoral head size of ≥ 36 mm. RESULTS:At the 8-year follow-up, the all-cause revision rate was higher in the DM group (3.5%, 95% confidence interval [CI] 3.1 to 4.1) compared to the ≤ 32-mm (2.6%, 95% CI 2.5 to 2.8) and ≥ 36-mm (2.7%, 95% CI 2.5 to 2.9) groups. However, the revision rate for instability was comparable among the DM (0.4%, 95% CI 0.2 to 0.5), ≤ 32 mm (0.5%, 95% CI 0.4 to 0.5), and ≥ 36 mm (0.3%, 95% CI 0.3 to 0.4) groups at 8-year follow-up. CONCLUSIONS:The utilization of DM was associated with higher overall revision rates. However, no significant differences in rates of revision for instability were observed among any of the bearing surface groups. These findings may be attributed to surgeons selectively utilizing DM articulations in higher-risk patients.