Timing and Factors Associated With Revision for Infection After Primary Total Knee Arthroplasty Based on American Joint Replacement Registry Data.

BACKGROUND: Infection following total knee arthroplasty (TKA) remains a challenging clinical problem. Using American Joint Replacement Registry data, this study examined factors related to the incidence and timing of infection. METHODS: Primary TKAs performed from January 2012 through December 2018 among patients ≥65 years of age at surgery were queried from the American Joint Replacement Registry and merged with Medicare data to enhance capture of revisions for infection. Multivariate Cox regressions incorporating patient, surgical, and institutional factors were used to produce hazard ratios (HRs) associated with revision for infection and mortality after revision for infection. RESULTS: Among 525,887 TKAs, 2,821 (0.54%) were revised for infection. Men had an increased risk of revision for infection at all-time intervals (≤90 days, HR = 2.06, 95% CI: 1.75-2.43, P < .0001; >90 days to 1 year, HR = 1.90, 95% CI: 1.58-2.28, P < .0001; >1 year, HR = 1.57, 95% CI: 1.37-1.79, P < .0001). TKAs performed for osteoarthritis had an increased risk of revision for infection at ≤90 days (HR = 2.01, 95% CI: 1.45-2.78, P < .0001) but not at later times. Mortality was more likely among patients who had a Charlson Comorbidity Index (CCI) ≥ 5 compared to those who had a CCI ≤ 2 (HR = 3.21, 95% CI: 1.35-7.63, P = .008). Mortality was also more likely among older patients (HR = 1.61 for each decade, 95% CI: 1.04-2.49, P = .03). CONCLUSION: Based on primary TKAs performed in the United States, men were found to have a persistently higher risk of revision for infection, while a diagnosis of osteoarthritis was associated with a significantly higher risk only during the first 90 days after surgery.

Dislocation Rates of Primary Total Hip Arthroplasty in Patients With Prior Lumbar Spine Fusion and Lumbar Degenerative Disk Disease With and Without Utilization of Dual Mobility Cups: An American Joint Replacement Registry Study.

INTRODUCTION: Patients undergoing primary total hip arthroplasty (THA) with a previous history of lumbar spine fusion (LSF) are at increased risk of dislocation. The purpose of this study was to compare the 90-day and 1-year dislocation rates of patients with LSF or lumbar degenerative disk disease who underwent primary THA with and without dual mobility (DM) constructs. METHODS: An American Joint Replacement Registry data set of patients aged 65 years and older undergoing primary THA with minimum 1-year follow-up with a history of prior LSF or a diagnosis of lumbar degenerative disk disease was created. DM status was identified, and dislocation and all-cause revision at 90 days and 1 year were assessed. RESULTS: A total of 15,572 patients met study criteria. The overall dislocation rates for the non-DM and DM groups were 1.17% and 0.68%, respectively, at 90 days, and 1.68% and 0.91%, respectively, at 1 year ( P = 0.005). The odds of 90-day (OR = 0.578, [ P = 0.0328]) and 1-year (OR = 0.534, [ P = 0.0044]) dislocation were significantly less with DM constructs, compared with non-DM constructs. No statistically significant difference was observed in revision rates between groups. DISCUSSION: This large registry-based study identified a reduced risk of dislocation in patients at risk for spinal stiffness when a DM compared with non-DM construct was used in primary THA at 90-day and 1-year follow-up intervals. Our data support the use of DM constructs in high-risk patients with stiff spines and altered spinopelvic mobility as a promising option to mitigate the risk of postoperative hip instability after primary THA. LEVELS OF EVIDENCE: Level III. Therapeutic retrospective cohort.

The James A. Rand Young Investigator's Award: Increased Revision Risk With Mobile Bearings in Total Knee Arthroplasty: An Analysis of the American Joint Replacement Registry.

BACKGROUND: Mobile-bearing (MB) total knee arthroplasty (TKA) may reduce wear and improve patellar tracking but may increase revision risk due to tibial component design, balance complexity, and bearing dislocation. We utilized the American Joint Replacement Registry to examine risk of revision with MB compared to fixed-bearing (FB) designs. METHODS: An analysis of primary TKA in patients over 65 years was performed with American Joint Replacement Registry data linked to Centers for Medicare and Medicaid Services data from 2012 to 2019. Analyses compared MB to FB designs with a subanalysis of implants from a single company. We identified 485,024 TKAs, with 452,199 (93.2%) FB-TKAs and 32,825 (6.8%) MB-TKAs. Cox proportional hazards regression modeling was used for all-cause revision and revision for infection, adjusting for sex, age, and competing risk of mortality. Event-free survival curves evaluated time to all-cause revision and revision for infection. RESULTS: MB-TKAs were at an increased risk for all-cause revision: hazard ratio (HR) 1.36 ([95% confidence interval (CI) 1.24-1.49], P < .0001) but not revision for infection: HR 1.06 ([95% CI 0.90-1.25], P = .52). When comparing implants within a single company, MB-TKAs were at an increased risk of all-cause revision: HR 1.55 ([95% CI 1.38-1.73], P < .0001). Event-free survival curves demonstrated increased risk for all-cause revision for MB-TKA across all time points, with a greater magnitude of risk up to 8 years. CONCLUSION: Although survivorship of both designs was outstanding, MB-TKA designs demonstrated increased risk for all-cause revision. Additional investigation is needed to determine if this is related to patient selection factors, surgical technique, bearing, or implant design.

No Reduction in Revision Risk Associated With Highly Cross-linked Polyethylene With or Without Antioxidants Over Conventional Polyetheylene in TKA: An Analysis From the American Joint Replacement Registry.

BACKGROUND: Highly cross-linked polyethylene (HXLPE) can improve wear properties in TKA, but it can also lead to decreased mechanical properties. Antioxidants were added to HXLPE to improve its mechanical properties while retaining the improved wear characteristics. However, it remains unclear whether these modifications to conventional polytheylene used in TKA have resulted in a change in the revision risk. QUESTIONS/PURPOSES: We used American Joint Replacement Registry data to ask: (1) Is there a difference in all-cause revision in patients who underwent TKA using HXLPE with or without an antioxidant doping compared with conventional polyethylene? (2) Is there a difference in revision for aseptic failure in patients who underwent TKA using HXLPE with or without an antioxidant doping compared with conventional polyethylene? METHODS: We analyzed American Joint Replacement Registry data from 2012 to 2019. We identified 339,366 primary TKAs over the study period in patients older than 65 years and linked procedures to supplemental Centers for Medicare & Medicaid data where available. Patient total number of reported comorbidities, gender, age, region, polyethylene characteristics, procedure dates, and indication for revision were recorded. Median follow-up was 34 months. We compared HXLPE with or without antioxidants to conventional polyethylene. Event-free percent survival curves and Cox proportional hazard regression modeling was used for all-cause revision and revision for aseptic failure. RESULTS: Compared with conventional polyethylene, there was no difference in all-cause revision with HXLPE with an antioxidant (HR 1.06 [95% CI 0.98 to 1.14]; p = 0.13) or HXLPE without an antioxidant (HR 1.04 [95% CI 0.97 to 1.11]; p = 0.28). Compared with conventional polyethylene, there was no difference in revision for aseptic failure with HXLPE with an antioxidant (HR 1.07 [95% CI 0.99 to 1.14]; p = 0.08) or HXLPE without an antioxidant (HR 1.03 [95% CI 0.97 to 1.01]; p = 0.30). CONCLUSION: We found no difference in revision risk between HXLPE with or without an antioxidant and conventional polyethylene during this time frame. HXLPE polyethylene, with or without an antioxidant, should not be widely adopted until or unless it is shown to be superior to conventional polyethylene in TKA. LEVEL OF EVIDENCE: Level III, therapeutic study.

Revision Risk for Total Knee Arthroplasty Polyethylene Designs in Patients 65 Years of Age or Older: An Analysis from the American Joint Replacement Registry.

BACKGROUND: Polyethylene bearing design may influence the risk of revision after total knee arthroplasty (TKA). Previous investigations from outside of the United States have suggested the potential for an increased risk of all-cause revision and revision for infection with the use of posterior-stabilized bearings. We examine the risk of revision based on the polyethylene bearing design selection for primary TKA. METHODS: An analysis of the American Joint Replacement Registry (AJRR) data from 2012 to 2019 was performed. We identified all primary TKAs over the study period and linked cases to supplemental U.S. Centers for Medicare & Medicaid Services (CMS) data where available. Patient demographic characteristics, polyethylene characteristics, procedure dates, and cause for revision were recorded. Analysis was performed to compare minimally stabilized implants (cruciate-retaining, anterior-stabilized, or pivot bearing designs) with posterior-stabilized implants. Cumulative incidence function (CIF) curves and Cox proportional hazard ratios (HRs) were created for all-cause revision and revision for infection in each group. RESULTS: We identified 305,279 cases with reported minimally stabilized or posterior-stabilized implant characteristics. There were 161,486 cases (52.9%) that utilized posterior-stabilized bearings compared with 143,793 cases (47.1%) with minimally stabilized bearings. For minimally stabilized bearings, 1,693 cases (1.18%) had all-cause revision and 334 cases (0.23%) had revision for infection. For posterior-stabilized bearings, 2,406 cases (1.49%) had all-cause revision and 446 cases (0.28%) had revision for infection. The use of posterior-stabilized bearings had HRs of 1.25 (95% confidence interval [CI], 1.2 to 1.3; p < 0.0001) for all-cause revision and 1.18 (95% CI, 1.0 to 1.4; p = 0.02) for revision for infection. CONCLUSIONS: Similar to investigations from international registries, we found an increased risk of all-cause revision and revision for infection when using posterior-stabilized bearings in TKA in the United States. Surgeons should consider this finding when considering bearing selection for primary TKA. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Trends in Polyethylene Design and Manufacturing Characteristics for Total Knee Arthroplasty: An Analysis From the American Joint Replacement Registry.

BACKGROUND: Advances in polyethylene bearing characteristics have led to various options for total knee arthroplasty. We examine trends in use of polyethylene in the United States. METHODS: An analysis of American Joint Replacement Registry data from 2012 to 2019 for primary total knee arthroplasty procedures was conducted. Design and manufacturing characteristics were obtained and validated in the American Joint Replacement Registry dataset. Polyethylene bearing design and manufacturing use characteristics were compared by year, gender, age group, and geographic region of the procedure. Descriptive analysis was performed. RESULTS: We identified 993,292 cases over the study period. In total, 791,233 (80%) cases had complete device data available and were included in analysis. In addition, 366,280 (49.4%) cases utilized minimally stabilized bearings compared to 374,809 (50.6%) for posterior-stabilized bearings. Posterior-stabilized use was stable over the study period and highest in the Northeast (64.5%; P < .0001). Cruciate-retaining use decreased from 29.7% to 20.2% and anterior-stabilized use increased from 17.4% to 25.2%. Conventional polyethylene use decreased from 42.8% to 21.9%, and was highest in the 81+ age group (37.8%; P < .0001) and Northeast (43.0%; P < .0001). Highly cross-linked polyethylene (HXLPE) with antioxidant use increased from 9.08% to 31.8%, while HXLPE without antioxidant use remained constant. CONCLUSION: There was an increase in use of anterior-stabilized and pivot bearings and an increase in use of HXLPE with antioxidant. Additionally, there were noted age group and regional differences in the use of various bearings. Further study should evaluate if these changing utilization trends are related to clinical outcomes, or due to regional training, preferences, or manufacturer pressures. LEVEL OF EVIDENCE: Level III, retrospective.

Migration Patterns for Revision Total Hip Arthroplasty in the United States as Reported in the American Joint Replacement Registry.

BACKGROUND: Revision total hip arthroplasty (revTHA) is associated with higher rates of complications and greater costs than primary procedures. The aim of this study is to evaluate the effect of hospital size, teaching status, and indication for revTHA, on migration patterns in patients older than 65 years old. METHODS: All THAs and revTHAs reported to the American Joint Replacement Registry from 2012 to 2018 were included and merged with the Centers for Medicare and Medicaid Services database. Migration rate was defined as a patient's THA and revTHA procedures that were performed at separate institutions by different surgeons. Migratory patterns were recorded based on hospital size, teaching status, and indication for revTHA. Analyses were performed by statisticians. RESULTS: The number of linked procedures included was 11,906. Migration rates in revTHA due to infection were higher for small hospitals than large hospitals (46.6% vs 28.6%, P < .0001). Migration rates were higher comparing non-teaching with teaching hospitals (55% vs 34%, P < .0001). This difference was significant for periprosthetic fractures (70.6% vs 37.2%, P = .005), instability (56.5% vs 35.5%, P = .04), and mechanical complications (88.9% vs 34.7%, P < .05). Most patients migrated to medium or large hospitals rather than small hospitals (89% vs 11%, P < .0001) and to teaching rather than non-teaching institutions (82% vs 18%, P < .0001). CONCLUSION: Hospital size and teaching status significantly affected migration patterns for revTHA. Migration rates were significantly higher in small non-teaching hospitals in revTHA due to infection, periprosthetic fracture, instability, and mechanical complications. Over 80% of patients migrated to larger teaching hospitals.

Emergency Department Visits Following Joint Replacement Surgery in an Era of Mandatory Bundled Payments.

OBJECTIVES: The Center for Medicare & Medicaid Services (CMS) is actively testing bundled payments models. This study sought to identify relevant details for 90-day postdischarge emergency department (ED) visits of Medicare beneficiaries following total joint replacement (TJR) surgery meeting eligibility for a CMS bundled payment program. METHODS: The CMS research identifiable file for the State of Texas for 2011-2012 was used to identify patients who underwent TJR. Qualifying inpatient claims were linked to 90-day postdischarge ED claims. The claims associated with live discharge were divided into three cohorts: elective total hip replacement (THR), emergent (THR), and total knee replacement. The frequency, distribution, diagnoses, and disposition for these ED visits were identified and stratified by timing within the postdischarge period as well as discharge diagnosis. Visits were correlated with age, sex, joint replaced, and fracture. RESULTS: There were 50,838 TJR surgeries in Texas in 2011-2012 that would have been eligible for inclusion in the CMS defined CJR program. A total of 12,747 ED visits by 9,299 patients occurred in the 90-day postdischarge period. Visits to the ED by patients 85 and older predominated in the case of THR performed secondary to a hip fracture. Patients 65-74 years predominated in both elective surgery categories. There were 2,370 ED visits within 90 days of 10,786 elective THRs, of which 55.5% were discharged home, 34.6% were hospitalized or transferred, and 6.9% were admitted to observation. Of the 3,438 ED visits among 8,475 emergent hip replacement cases, 22.4% were discharged home, 50.2% were hospitalized or transferred, and 5.3% were admitted to observation. Of the 6,939 visits among 31,387 knee replacement cases, 61.9% were discharged home, 30.6% were readmitted or transferred, and 7.1% were admitted to observation. The discharge diagnoses varied by volume and timing in the postdischarge period. The most prevalent diagnoses across groups included injury/trauma, physiologic decompensation, cardiopulmonary events, and infection. CONCLUSIONS: ED services are frequent for Medicare TJR bundle-eligible patients within the postdischarge period. ED utilization, discharge diagnosis and disposition varied by age, and elective and emergent surgeries. The ED is an important site for identifying and managing postoperative adverse outcomes.