The James A. Rand Young Investigator's Award: Keeping It Simple: Are all Musculoskeletal Infection Society Tests Useful to Diagnose Periprosthetic Joint Infection?

BACKGROUND: Current data evaluating the clinical value and cost-effectiveness of advanced diagnostic tests for periprosthetic joint infection (PJI) diagnosis, including alpha-defensin and synovial C-reactive protein (CRP), is conflicting. This study aimed to evaluate the adequacy of preoperative and intraoperative PJI workups without utilizing these tests. METHODS: This retrospective analysis identified all patients who underwent revision total knee or hip arthroplasty (rTKA and rTHA, respectively) for suspected PJI between 2018 and 2020 and had a minimum follow-up of 2 years. Perioperative data and lab results were collected, and cases were dichotomized based on whether they met the 2018 Musculoskeletal Infection Society (MSIS) criteria for PJI. In total, 204 rTKA and 158 rTHA cases suspected of PJI were reviewed. RESULTS: Nearly 100% of the cases were categorized as "infected" for meeting the 2018 MSIS criteria without utilization of alpha-defensin or synovial CRP (rTKA: n = 193, 94.6%; rTHA: n = 156, 98.7%). Most cases were classified as PJI preoperatively by meeting either the major MSIS or the combinational minor MSIS criteria of traditional lab tests (rTKA: n = 177, 86.8%; rTHA: n = 143, 90.5%). A subset of cases was classified as PJI by meeting combinational preoperative and intraoperative MSIS criteria (rTKA: 16, 7.8%; rTHA: 13, 8.2%). Only 3.6% of all cases were considered "inconclusive" using preoperative and intraoperative data. CONCLUSIONS: Given the high rate of cases satisfying PJI criteria during preoperative workup using our available tests, the synovial alpha-defensin and synovial CRP tests may not be necessary in the routine diagnostic workup of PJI. We suggest that the primary PJI workup process should be based on a stepwise algorithmic approach with the most economical testing necessary to determine a diagnosis first. The use of advanced, commercialized, and costly biomarkers should be utilized only when traditional testing is indeterminate.

Indications, Clinical Outcomes, and Re-Revisions Following Revision Total Hip Arthroplasty - Does Age Matter?

BACKGROUND: Younger age is associated with increased revision incidence following primary total hip arthroplasty, though the association between age and repeat revision following revision total hip arthroplasty (rTHA) has not been described. This study aimed to describe the incidences and indications for subsequent revision (re-revision) following rTHA based on age. METHODS: Patients undergoing aseptic rTHA from 2011 to 2021 with minimum 1-year follow-up were retrospectively reviewed. Patients were stratified into 3 groups based on age at the time of index rTHA (ie, <55 years, 55 to 74 years, and >74 years). Perioperative characteristics, complications, and re-revisions were compared between groups. RESULTS: Of 694 included rTHAs, those in the >74 age group were more likely to undergo rTHA for periprosthetic fracture (P < .001) while those in the <55 age group were more likely to undergo rTHA for metallosis/taper corrosion (P = .028). Readmissions (P = .759) and emergency department visits (P = .498) within 90 days were comparable across ages. Rates of re-revision were comparable at 90 days (P = .495), 1 year (P = .443), and 2 years (P = .204). Kaplan-Meier analysis of all-cause re-revision at latest follow-up showed a nonstatistically significant trend toward increasing re-revisions in the <55 and 55 to 74 age groups. Using logistic regressions, smoking and index rTHA for instability were independently associated with re-revision, while age at index surgery was not. CONCLUSIONS: While indications for rTHA differ across age groups, rates of 2-year re-revision are statistically comparable between groups. Further studies are warranted to understand the association between age, activity, and re-revision rates after 5 years postoperatively.

The accuracy of component positioning during revision total hip arthroplasty using 3D optical computer-assisted navigation.

INTRODUCTION: Despite the excellent outcomes associated with primary total hip arthroplasty (THA), implant failure and revision continue to burden the healthcare system. The use of computer-assisted navigation (CAN) offers the potential for more accurate placement of hip components during surgery. While intraoperative CAN systems have been shown to improve outcomes in primary THA, their use in the context of revision total hip arthroplasty (rTHA) has not been elucidated. We sought to investigate the validity of using CAN during rTHA. METHODS: A retrospective analysis was performed at an academic medical institution identifying all patients who underwent rTHA using CAN from 2016-2019. Patients were 1:1 matched with patients undergoing rTHA without CAN (control) based on demographic data. Cup anteversion, inclination, change in leg length discrepancy (ΔLLD) and change in femoral offset between pre- and post-operative plain weight-bearing radiographic images were measured and compared between both groups. A safety target zone of 15-25° for anteversion and 30-50° for inclination was used as a reference for precision analysis of cup position. RESULTS: Eighty-four patients were included: 42 CAN cases and 42 control cases. CAN cases displayed a lower ΔLLD (5.74 ± 7.0 mm vs 9.13 ± 7.9 mm, p = 0.04) and greater anteversion (23.4 ± 8.53° vs 19.76 ± 8.36°, p = 0.0468). There was no statistical difference between the proportion of CAN or control cases that fell within the target safe zone (40% vs 20.9%, p = 0.06). Femoral offset was similar in CAN and control cases (7.63 ± 5.84 mm vs 7.14 ± 4.8 mm, p = 0.68). CONCLUSION: Our findings suggest that the use of CAN may improve accuracy in cup placement compared to conventional methodology, but our numbers are underpowered to show a statistical difference. However, with a ΔLLD of ~ 3.4 mm, CAN may be useful in facilitating the successful restoration of pre-operative leg length following rTHA. Therefore, CAN may be a helpful tool for orthopedic surgeons to assist in cup placement and LLD during complex revision cases.

Outcomes of medicaid patients undergoing TJA with previous positive urine toxicology screens.

INTRODUCTION: Previous studies have demonstrated that patients with positive preoperative urine toxicology (utox) screens prior to total joint arthroplasty (TJA) have higher readmission rates, greater complication rates, and longer hospital stays compared to patients with negative screens. The aim of this study was to investigate the effect of postponing surgery for patients with positive preoperative utox in the Medicaid population. METHODS: This retrospective, observational study reviewed the Medicaid ambulatory database at a large, academic orthopedic specialty hospital for patients with a utox screen prior to TJA from 2012 to 2020. Patients were categorized into three groups: (1) controls with negative preoperative utox or a utox consistent with prescription medications (Utox-) with TJA completed as scheduled; (2) positive preoperative utox with TJA rescheduled and surgery completed on a later date (R-utox+); (3) positive preoperative utox inconsistent with prescription medications with TJA completed as scheduled (S-utox+). Primary outcomes included mortality, 90-day readmission rate, complication rate, and length of stay. RESULTS: Of the 300 records reviewed, 185 did not meet inclusion criteria. The remaining 115 patients included 80 (69.6%) Utox-, 5 (6.3%) R-utox+, and 30 (37.5%) S-utox+. Mean follow-up time was 49.6 months. Hospital stays trended longer in the Utox- group (3.7 ± 2.0 days vs. 3.1 ± 1.6 S-utox+ vs.2.5 ± 0.4 R-utox+, p = 0.20). Compared to the R-utox+group, the S-utox+ group trended toward lower home discharge rates (p = 0.20), higher in-hospital complication rates (p = 0.85), and more all-cause 90-day emergency department visits (p = 0.57). There were no differences in postoperative opioid utilization between groups (p = 0.319). Duration of postoperative narcotic use trended toward being longer in the Utox- patients (820.7 ± 1073.8 days vs. 684.6 ± 1491.8 S-utox+ vs. 585.1 ± 948.3 R-utox+, p = 0.585). Surgical time (p = 0.045) and revision rates (p = 0.72) trended toward being higher in the S-utox+ group. CONCLUSIONS: Medicaid patients with positive preoperative utox who had surgeries postponed trended towards shorter hospital stays and greater home discharge rates. Larger studies should be conducted to analyze the implications of a positive preoperative utox on risk profiles and outcomes following TJA in the Medicaid population. Study design Retrospective cohort study.

Prior Instability is Strongly Associated With Dislocation After Isolated Head and Liner Exchange.

BACKGROUND: Isolated head and liner exchange is an appealing alternative to a more extensive revision total hip arthroplasty in patients who have well-fixed components. Despite efforts to increase femoral offset and restore soft tissue tensioning, limited component revision may be associated with higher rates of postoperative instability. METHODS: This retrospective analysis assessed 209 patients who had a head and liner exchange conducted at a large academic medical center between 2011 and 2019 and had >2 years of follow-up. Functional cup positioning within the Lewinnek safe zone was assessed on postoperative weight-bearing radiographs. Included patients were 56% women, had a mean age of 64 years (range, 24-89) and a mean body mass index of 28.8 kg/m2 (range, 18.2-46.7). The most common indications for surgery included acetabular liner wear in 86 hips (41%), instability in 40 hips (19%), and infection in 36 hips (17%). RESULTS: Twenty-eight hips (13%) had a dislocation within 2 years after surgery. The best-fit model predicting postoperative dislocation included a history of dislocation (adjusted-odds ratio [adj-OR] 5.67, 95% CI 2.39-14.09, P < .001), age (adj-OR 1.04 per 1-year increase, 95% CI 0.99-1.08, P = .10), and body mass index (adj-OR 0.90 per 1-kg/m2 increase, 95% CI 0.80-0.99, P = .046). CONCLUSION: In a large cohort of patients who had isolated head and liner exchange, patients who had prior instability had 7-fold elevated odds of postoperative dislocation. This risk remains significant after controlling for cup positioning outside the Lewinnek safe zone, liner type, head size, neck length, soft tissue compromise, neuromuscular disease, and dual mobility constructs. LEVEL OF EVIDENCE: III, retrospective cohort study.

Has There Been a Change in the Age of Presentation of Patients With DDH After the Implementation of a Dedicated Ultrasound-screening Program?

BACKGROUND: We sought to determine if the age of patients presenting to a tertiary subspecialty hospital dedicated to pediatric orthopaedics has changed over the last 21 years and determine if a dedicated ultrasound-screening program implemented in 2006 made any difference. METHODS: We reviewed the hospital charts for 9299 patients diagnosed with developmental dysplasia of the hip (DDH) and determined the age at the time of presentation; this was a consecutive series of all patients presenting between 1998 and 2019. We determined the diagnosis and age from the chart, 8011 were female (86.15%), and 1288 were male (13.85%). The left hip was affected in 4588 cases (49.34%), the right hip in 1824 cases (19.62%), and there were 2887 bilateral cases (31.05%). RESULTS: Over the 21 years, the mean age of presentation was 2.36 years (range, 0.1 to 17 y). In 1998, the mean age was 2.49 years (range, 0.1 to 16 y). In 2006, a dedicated ultrasound-screening clinic was instituted. The mean age decreased to 1.70 years in 2019 (range, 0.1 to 14 y). The mean age at presentation decreased significantly from 2.65 years, between 1998 and 2005, to 2.19 between 2006 and 2019 (P=0.0067). CONCLUSIONS: The implementation of a dedicated ultrasound-screening protocol was significantly correlated with a decrease in the mean age of diagnosis of DDH. The results of treatment of DDH are known to be better the sooner the diagnosis is made. Given that the age of presentation remains a challenge, especially in developing countries, a dedicated ultrasound-screening program is one step to improve our ability to detect DDH in patients at a younger age. LEVEL OF EVIDENCE: Level IV-diagnostic.

What Are the Rate and Risk Factors for Developing a Complication With the Pavlik Method for the Treatment of Hip Dysplasia?

BACKGROUND: The Pavlik method for the treatment of developmental dysplasia of the hip (DDH) has been proven successful for over 85 years. The high success rate and reproducibility have made it the mainstay of treatment. METHODS: We performed a retrospective cohort study of patients with DDH treated with the Pavlik method between September 2016 and August 2018 with at least 24 months of follow up in a single academic center. We excluded patients with neuromuscular conditions, teratologic dislocations, and arthrogryposis. We identified and included a total of 307 patients in the analysis. There were 66 patients with dysplasia, 97 with instability, and 144 with a dislocation. Data collected included age at initiation of the Pavlik method, diagnosis (isolated dysplasia, subluxation, or dislocation), duration of treatment, follow up duration and any complication. At final follow up, anteroposterior radiographs of the pelvis were used to determine the Severin classification. RESULTS: Major complications were proximal femoral growth disturbance (5.8%) and femoral nerve palsy (0.98%). Multivariate analysis showed that an initial diagnosis of a dislocated hip (odds ratio, 2.20; P<0.01), was significantly associated with developing a complication. At final follow up, we found Severin type I or II radiographic findings in 100% of patients with dysplasia, 95% of patients with instability and 54% of patients with dislocation (P=0.001). CONCLUSIONS: Complications are not entirely uncommon when the Pavlik method is used for the treatment of DDH. The overall rate of major complications was 7%. The Pavlik method is safe, and independent risk factors for complications were being over 5 months of age and having a dislocated hip at initial presentation. LEVEL OF EVIDENCE: Level IV-cohort study.

ICD-10 Coding Mismatch in Computer and Robotic Assisted Primary Total Hip Arthroplasty.

BACKGROUND: The International Statistical Classification of Disease, 10th Revision Procedural Coding System (ICD-10-PCS) is a granular procedural classification system with the ability to precisely classify types of technology utilized in total hip arthroplasty (THA). However, coding nuances and the rapidly evolving nature of technology may lead to coding inaccuracies. The purpose of this study is to determine the accuracy of ICD-10-PCS coding in computer-navigated and robotic THA and discuss its implications on clinical data. METHODS: The arthroplasty database at a single institution was retrospectively reviewed for all primary computer and robotic assisted THAs performed between October 2015 to November 2020. The type of technology utilized was determined from the surgical record and compared with the ICD-10-PCS codes applied to each procedure. RESULTS: A total of 3721 technology-assisted THAs were identified and reviewed. 87.5% of technology-assisted THAs were coded with the correct type of technology. The most common error in computer navigated THA was the omission of the technology code, while the most common error in robotic assisted THA was the designation of codes for both computer navigation and robotic assistance. CONCLUSION: The granular nature of ICD-10-PCS allows for precise distinction between types of technology-assisted THA. However, rates of coding inaccuracy bring concern for the integrity of this data. The inaccuracy of ICD-10-PCS data is not insignificant and should bring concern for the validity of collective data sets that use it exclusively for its procedural granularity.

Factors Affecting Range of Motion After Revision Total Knee Arthroplasty.

BACKGROUND: Range of motion (ROM) after revision total knee arthroplasty (RTKA) is an important clinical outcome, as decreased ROM can lead to patient dissatisfaction and diminished mobility. This study sought to determine the effect of type of revision, implant constraint level, and reason for revision has on RTKA ROM. METHODS: A retrospective review of 832 RTKA cases from 2011 to 2019 was conducted at a single, urban academic institution. Patients who underwent aseptic RTKA and had preoperative and 1-year postoperative ROM in their chart were included. The ΔROM was calculated by subtracting the preoperative ROM from the 1-year postoperative ROM. ROM was compared between tibial polyethylene liner-only revisions (liner) and all other revision types (component) and based on reason for revision. Subanalysis was performed within the liner and component revision cohorts to determine the effect of reason for revision and implant constraint level on ROM. RESULTS: In total, 290 patients qualified. Forty-two patients had liner revisions (14.5%) and 248 had component revisions (85.5%). The ΔROM for component revision cases was significantly higher than liner exchange only (10° ± 24° vs.1° ± 19°; P = .03). ΔROM was not significant when comparing the level of implant constraint nor was it when separating and comparing by type of revision. Component revisions due to instability were found to significantly decrease ΔROM. CONCLUSION: Component revision cases have significantly improved ΔROM when compared with liner-only revision. Constraint level is not significantly associated with changes in ROM in either liner or component revisions. Component revisions due to instability significantly reduce ΔROM.

The Effect of Medicare's Bundled Payments for Care Initiative on Patient Risk Factors Prior to Total Knee Arthroplasty.

BACKGROUND: Medicare's Bundled Payments for Care Initiative (BPCI) is a risk-sharing alternative payment model. There is a concern that BPCI providers may avoid operating on obese patients and active smokers to reduce costs. We sought to understand if increased focus on these patient factors has led to a change in patient demographics in Medicare-insured patients undergoing total knee arthroplasty (TKA). METHODS: We retrospectively reviewed all patients who underwent TKA at an academic orthopedic specialty hospital between 1/1/13 and 8/31/19. Surgical date, insurance provider, BMI, and smoking status were collected. Patients were categorized as a current, former, or never smoker. Patients were categorized as obese if their BMI was >30 kg/m2, morbidly obese if their BMI was >40 kg/m2, and super obese if their BMI was >50 kg/m2. RESULTS: In total, 10,979 patients with complete insurance information were analyzed. There was no statistically significant change in the proportion of Medicare patients who were active smokers (4.34% in 2013, 4.85% in 2019, Pearson correlation coefficient = 0.6092, P = .146). The proportion of Medicare patients with BMI >30 kg/m2 increased over the study period (35.84% in 2013, 55.77% in 2019, Pearson correlation coefficient = 0.8505, P = .015). When looking at patients with BMI >40 kg/m2 and >50 kg/m2, there was no significant change. CONCLUSIONS: Despite concern that reimbursement payments could alter access to care for patients with certain risk factors, this study did not find a noticeable difference in the representation of patients with obesity and smoking status undergoing TKA following the installation of BPCI. LEVEL OF EVIDENCE: III, retrospective observational analysis.

Early, Mid-Term, and Late-Term Aseptic Femoral Revisions After THA: Comparing Causes, Complications, and Resource Utilization.

BACKGROUND: Registry data suggest increasing rates of early revisions after total hip arthroplasty (THA). We sought to analyze modes of failure over time after index THA to identify risk factors for early revision. METHODS: We identified 208 aseptic femoral revision THAs performed between February 2011 and July 2019 using an institutional database. We compared demographics, diagnoses, complications, and resource utilization between aseptic femoral revision THA occurring within 90 days (early), 91 days to 2 years (mid), and greater than 2 years (late) after index arthroplasty. RESULTS: Early revisions were 33% of revisions at our institution in the time period analyzed. Periprosthetic fractures were 81% of early, 27% of mid, and 21% of late femoral revisions (P < .01). Women were more likely to have early revisions than men (75% vs 53% of mid and 48% of late revisions; P < .01). Patients who had early revisions were older (67.97 ± 10.06) at the time of primary surgery than those who had mid and late revisions (64.41 ± 12.10 and 57.63 ± 12.52, respectively, P < .01). Index implants were uncemented in 99% of early, 96% of mid, and 64% of late revisions (P < .01). Early revisions had longer postoperative length of stay (4.4 ± 3.3) than mid and late revisions (3.0 ± 2.2 and 3.7 ± 2.1, respectively, P = .02). In addition, 58% of early revisions were discharged to an inpatient facility compared with 36% of mid and 41% of late revisions (P = .03). CONCLUSION: Early aseptic femoral revisions largely occur in older women with uncemented primary implants and primarily due to periprosthetic fractures. Reducing the incidence of periprosthetic fractures is critical to decreasing the large health care utilization of early revisions.

How Accurate Is ICD-10 Coding for Revision Total Knee Arthroplasty?

BACKGROUND: The International Classification of Diseases-10 (ICD-10) came into effect in October 2015. The new procedural codes (ICD-10-PCS) were designed to specify granular aspects of the procedure, including laterality and revised components. This specificity could improve data collection in institutional databases, large registries, and administrative claims data. Given these possible applications, this study's purpose was to assess the accuracy of ICD-10-PCS coding for revision total knee arthroplasty (rTKA). METHODS: This multicenter retrospective analysis utilized the rTKA databases at four academic medical centers for all aseptic rTKAs between October 1, 2015 and July 3, 2019. Operative reports were reviewed to determine laterality and revised components (tibial, femoral, liner, and patellar component), which were then compared with the ICD-10-PCS codes associated with the billing records. Proper coding required both component removal and replacement codes. The correct series of removal and replacement codes was determined using the American Joint Replacement Registry's guidelines. RESULTS: In total, 1906 rTKAs were examined, and 98.0% had at least one proper ICD-10-PCS code, indicating an rTKA had occurred. Coding for components replaced was correct in 76.3% of cases. When examining both removal and replacement codes, accuracy dropped to 57.0%. CONCLUSION: Nearly 25% of rTKA procedures were incorrectly coded for replaced components, and over 40% were incorrectly coded for removed and replaced components. ICD-10-PCS codes can accurately identify that an rTKA has occurred; however, the inaccuracy in identifying which specific components were revised should prompt further evaluation of the coding process before utilizing ICD-10-PCS codes to report granular rTKA data. LEVEL OF EVIDENCE: III, retrospective observational analysis.

Comparing the Efficacy of Articulating Spacer Constructs for Knee Periprosthetic Joint Infection Eradication: All-Cement vs Real-Component Spacers.

BACKGROUND: The most common treatment for periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is a 2-stage revision. Few studies have compared different articulating spacer constructs. This study compares the outcomes of real-component and all-cement articulating spacers for TKA PJI treatment. METHODS: This retrospective observational study examined the arthroplasty database at 3 academic hospitals for articulating spacers placed for TKA PJIs between April 2011 and August 2020. Patients were categorized as receiving a real-component or an all-cement articulating spacer. Data on demographics, surgical information, and outcomes were collected. RESULTS: One-hundred sixty-four spacers were identified: 72 all-cement and 92 real-component spacers. Patients who received real-component spacers were older (67 ± 10 vs 63 ± 12 years; P = .04) and more likely to be former smokers (50.0% vs 28.6%; P = .02). Real-component spacers had greater range of motion (ROM) after Stage 1 (84° ± 28° vs 58° ± 28°; P < .01) and shorter hospital stays after Stage 1 (5.8 ± 4.3 vs 8.4 ± 6.8 days; P < .01). There was no difference in time to reimplantation, change in ROM from pre-Stage 1 to most recent follow-up, or reinfection. Real-component spacers had shorter hospital stays (3.3 ± 1.7 vs 5.4 ± 4.9 days; P < .01) and operative times during Stage 2 (162.2 ± 47.5 vs 188.0 ± 66.0 minutes; P = .01). CONCLUSION: Real-component spacers had improved ROM after Stage 1 and lower blood loss, shorter operative time, and shorter hospital stays after Stage 2 compared to all-cement articulating spacers. The 2 spacer constructs had the same ultimate change in ROM and no difference in reinfection rates, indicating that both articulating spacer types may be safe and effective options for 2-stage revision TKA. LEVEL OF EVIDENCE: III, retrospective observational analysis.

The Inaccuracy of ICD-10 Coding in Revision Total Hip Arthroplasty and Its Implication on Revision Data.

BACKGROUND: The International Statistical Classification of Diseases, 10th Revision (ICD-10), was adopted by the United States on October 1, 2015 and expanded coding from 3800 codes with the International Statistical Classification of Diseases, Ninth Revision, procedure code system (ICD-9-PCS) to 73,000. The increase in number of codes was designed to create more accurate representations of procedures like revision total hip arthroplasties (rTHAs). However, many worry that the increased complexity leads to more inaccurate coding. The purpose of this study is to determine the accuracy of ICD-10-PCS coding for rTHA and discuss the implications on registry data. METHODS: The rTHA databases at 2 large, academic medical centers were retrospectively reviewed for all rTHAs between October 1, 2015 and July 3, 2019. The laterality and specific revised components were recorded and compared with the ICD-10-PCS codes used for each procedure. The accuracy of ICD-10-PCS codes relative to the surgical record was determined using coding guidelines published by the American Joint Replacement Registry (AJRR). RESULTS: Overall, 895 cases were reviewed. Replacement coding was 22% accurate (195 of 895). For removal and replacement coding, accuracy dropped to 17% (152 of 895). All procedures had at least 1 rTHA trigger code that would signify correctly to AJRR that an rTHA occurred. CONCLUSION: In this study, the percent of correctly coded rTHA was low. All rTHA procedures had at least 1 AJRR trigger code; therefore, an rTHA would have been appropriately captured by AJRR. But these inaccuracies should make one pause when using ICD-10-PCS procedural data to try to evaluate specific rTHA details from administrative claims databases and ward against expanding ICD-10-PCS as a means to collect implant survival and registry data.

What Are the Effects of Patient Point of Entry and Medicaid Status on Postoperative Opioid Consumption and Pain Following Primary Total Knee Arthroplasty?

BACKGROUND: Total knee arthroplasty (TKA) provides excellent results across a variety of pathologies. As greater focus is placed on the opioid epidemic, we sought to determine if patients presenting for TKA via the Medicaid clinic (Medicaid) differed in terms of their opioid requirements compared to patients presenting via private office clinics (non-Medicaid). METHODS: A single-institution total joint arthroplasty database was utilized to identify patients who underwent elective TKA between January 2016 and May 2019. Medicaid clinic patients were insured by some form of Medicaid, whereas private office patients had commercial or Medicare insurance. Morphine milligram equivalents (MMEs) and Activity Measure for Post-Acute Care scores were calculated. RESULTS: A total of 6509 patients were identified: 413 (6.35%) Medicaid and 6096 (93.65%) non-Medicaid. Medicaid patients were younger (63.32 vs 66.21 years, P < .0001), less likely to be of Caucasian race (21.31% vs 56.82%, P < .0001), and more likely to be active smokers (11.14% vs 7.73%, P < .0001). Although surgical time and home discharge rates were similar, Medicaid patients had longer length of stay (2.80 vs 2.46 days, P < .0001). Opioid requirements were higher for Medicaid patients (200.1 vs 132.2 MMEs, P < .0001), paralleling higher pain scores (3.03 vs 2.55, P < .0001). No differences were found in Activity Measure for Post-Acute Care scores (18.47 vs 18.77, P = .1824). CONCLUSION: Medicaid patients tended to be younger, of minority race, and active smokers compared to non-Medicaid patients. Medicaid patients demonstrated worse postoperative pain scores and required 51% greater MMEs immediately following TKA, highlighting the need for preoperative counseling in traditionally at-risk socioeconomic groups. LEVEL OF EVIDENCE: III, Retrospective Observational Analysis.

Do Patient Point of Entry and Medicaid Status Affect Quality Outcomes Following Total Knee Arthroplasty?

BACKGROUND: The effect of surgeon practice and patient care setting have not been studied in the Medicaid population undergoing total knee arthroplasty (TKA). This study aims to evaluate whether point of entry and Medicaid status affect outcomes following TKA. METHODS: The electronic medical record at our urban, academic, tertiary care hospital system was retrospectively reviewed for all primary, unilateral TKA during January 2016 and January 2018. Outpatient visits within the 6-month preoperative period categorized TKA recipients as either Hospital Ambulatory Clinic Centers patients with Medicaid insurance or private office patients with non-Medicaid insurers. RESULTS: There were 174 Medicaid patients and 317 non-Medicaid patients for 491 total patients. Medicaid patients were significantly younger (62.6 ± 1.6 vs 65.4 ± 1.1 years, P < .01), of "other' ethnicity (43.1% vs 25.6%, P < .01), and to be a current smoker (9.3% vs 6.6%, P = .02). There was no difference in gender, body mass index, and American Society of Anesthesiologists score. After controlling for patient factors, the Medicaid effect was insignificant for surgical time (exponentiated ß 0.93, 95% confidence interval [CI] 0.86-1.01, P = .076) and facility discharge (odds ratio 1.58, 95% CI 0.71-3.51, P = .262). Medicaid status had a significant effect on length of stay (LOS) (rate ratio 1.21, 95% CI 1.02-1.43, P = .026). CONCLUSION: Multivariable analysis controlling for patient factors demonstrated that Medicaid coverage had minimal effect on surgical time and facility discharge. Medicaid patients had significantly longer LOS by one-half day. These results indicate that comparable outcomes can be achieved for Medicaid patients following TKA provided that the surgeon and care setting are similar. However, increased care coordination and preoperative education may be necessary to normalize disparities in hospital LOS. LEVEL OF EVIDENCE: III, retrospective observational analysis.

Outcomes of isolated head-liner exchange versus full acetabular component revision in aseptic revision total hip arthroplasty.

INTRODUCTION: Isolated head and liner exchange in aseptic revision total hip arthroplasty (rTHA) is an appealing option rather than full acetabular component revision; however, early outcome reports suggest high rates of complications requiring re-revision. This study seeks to compare the outcomes of these procedures. METHODS: This retrospective study assessed 124 head and liner exchanges and 59 full acetabular cup revisions conducted at a single center between 2011 and 2019 with at least 2 years of follow-up. Baseline demographics did not vary by group. Mean follow-up was 3.7 (range 2.0-8.6) years. RESULTS: In the head and liner exchange group, re-revision-free survivorship at 2 years was 79% for all-causes and 84% for aseptic reasons. In the full acetabular revision group, it was 80% for all causes (p > 0.99) and 83% for aseptic reasons (p > 0.99). The 2-year survivorship of head and liner exchange was non-inferior to that of full acetabular revision, correcting for surgical indication and history of prior revision (adj-OR 0.1.39, 95% CI, 0.62-3.28, p = 0.99). A best-fit multivariable model found that revision for instability (adj-OR=3.03, 95% CI 1.40-6.66, p = 0.005), prior revision (adj-OR 2.15; 95% CI, 0.87-5.32; p = 0.10), current smoking (adj-OR 2.07; 95% CI, 0.94-4.57; p = 0.07), and obesity (adj-OR 0.58; 95% CI, 0.24-1.36; p = 0.22) were associated with failure within 2 years. CONCLUSIONS: In this analysis, 2-year outcomes for isolated head and liner exchange were non-inferior to full acetabular component revision. A future randomised prospective study should be conducted to better assess the optimal approach to revision in an aseptic failed hip arthroplasty.

Impact of time to revision total knee arthroplasty on outcomes following aseptic failure.

INTRODUCTION: Prior studies have demonstrated an association between time to revision total knee arthroplasty (rTKA) and indication; however, the impact of early versus late revision on post-operative outcomes has not been reported. MATERIALS AND METHODS: A retrospective, observational study examined patients who underwent unilateral, aseptic rTKA at an academic orthopedic hospital between 6/2011 and 4/2020 with > 1-year of follow-up. Patients were early revisions if they were revised within 2 years of primary TKA (pTKA) or late revisions if revised after greater than 2 years. Patient demographics, surgical factors, and post-operative outcomes were compared. RESULTS: 470 rTKA were included (199 early, 271 late). Early rTKA patients were younger by 2.5 years (p = 0.002). The predominant indications for early rTKA were instability (28.6%) and arthrofibrosis/stiffness (26.6%), and the predominant indications for late rTKA were aseptic loosening (45.8%) and instability (26.2%; p < 0.001). Late rTKA had longer operative times (119.20 ± 51.94 vs. 103.93 ± 44.66 min; p < 0.001). There were no differences in rTKA type, disposition, hospital length of stay, all-cause 90-day emergency department visits and readmissions, reoperations, and number of re-revisions. CONCLUSIONS: Aseptic rTKA performed before 2 years had different indications but demonstrated similar outcomes to those performed later. Early revisions had shorter surgical times, which could be attributed to differences in rTKA indication. LEVEL OF EVIDENCE: III, retrospective observational analysis.

Multiply revised TKAs have worse outcomes compared to index revision TKAs.

Aims: Revision total knee arthroplasty (rTKA) is a technically challenging and costly procedure. It is well-documented that primary TKA (pTKA) have better survivorship than rTKA; however, we were unable to identify any studies explicitly investigating previous rTKA as a risk factor for failure following rTKA. The purpose of this study is to compare the outcomes following rTKA between patients undergoing index rTKA and those who had been previously revised. Methods: This retrospective, observational study reviewed patients who underwent unilateral, aseptic rTKA at an academic orthopaedic speciality hospital between June 2011 and April 2020 with > one-year of follow-up. Patients were dichotomized based on whether this was their first revision procedure or not. Patient demographics, surgical factors, postoperative outcomes, and re-revision rates were compared between the groups. Results: A total of 663 cases were identified (486 index rTKAs and 177 multiply revised TKAs). There were no differences in demographics, rTKA type, or indication for revision. Multiply revised patients had significantly longer rTKA operative times (p < 0.001), and were more likely to be discharged to an acute rehabilitation centre (6.2% vs 4.5%) or skilled nursing facility (29.9% vs 17.5%; p = 0.003). Patients who had been multiply revised were also significantly more likely to have subsequent reoperation (18.1% vs 9.5%; p = 0.004) and re-revision (27.1% vs 18.1%; p = 0.013). The number of previous revisions did not correlate with the number of subsequent reoperations (r = 0.038; p = 0.670) or re-revisions (r = -0.102; p = 0.251). Conclusion: Multiply revised TKA had worse outcomes, with higher rates of facility discharge, longer operative times, and greater reoperation and re-revision rates compared to index rTKA.

Impact of revision TKA indications on resource utilization.

BACKGROUND: Indications for surgery may impact resource utilization in aseptic revision total knee arthroplasty (rTKA), and understanding these relationships would facilitate risk-stratification preoperatively. The purpose of this study was to investigate the impact of rTKA indications on readmission, reoperation, length of stay (LOS), and cost. METHODS: We reviewed all 962 patients who underwent aseptic rTKA at an academic orthopedic specialty hospital between June 2011-April 2020 with at least 90 days of follow-up. Patients were categorized based on their indication for aseptic rTKA as listed in the operative report. Demographics, surgical factors, LOS, readmission, reoperation and cost were compared between cohorts. RESULTS: There were significant differences in operative time among cohorts (p < 0.001), highest among the periprosthetic fracture group (164.2 ± 59.8 min). Reoperation rate was greatest in the extensor mechanism disruption cohort (50.0 %, p = 0.009). Total cost differed significantly among groups (p < 0.001), which was highest among the implant failure cohort (134.6 % of mean) and lowest for component malpositioning cohort (90.2 % of mean). Similarly, there were significant differences in direct cost (p < 0.001) which was highest in the periprosthetic fracture cohort (138.5 % of mean), and lowest in the implant failure cohort (90.5 % of mean). There were no differences in discharge disposition, or number of re-revisions among all groups. CONCLUSIONS: Operative time, components revised, LOS, readmissions, reoperation rate, total cost and direct cost following aseptic rTKA varied significantly between different revision indications. These differences should be noted for preoperative planning, resource allocation, scheduling, and risk-stratification. LEVEL OF EVIDENCE: III, retrospective observational analysis.