Improvements in Quality, Safety and Costs Associated with Use of Implant Registries Within a Health System.

BACKGROUND: Clinical quality registries (CQRs) are intended to enhance quality, safety, and cost reduction using real-world data for a self-improving health system. Starting in 2001, Kaiser Permanente established several medical device CQRs as a quality improvement initiative. This report examines the contributions of these CQRs on improvement in health outcomes, changes in clinical practice, and cost-effectiveness over the past 20 years. METHODS: Eight implant registries were instituted with standardized collection from the electronic health record and other institutional data sources of patient characteristics, medical comorbidities, implant attributes, procedure details, surgical techniques, and outcomes (including complications, revisions, reoperations, hospital readmissions, and other utilization measures). A rigorous quality control system is in place to improve and maintain the quality of data. Data from the Implant Registries form the basis for multiple quality improvement and patient safety initiatives to minimize variation in care, promote clinical best practices, facilitate recalls, perform benchmarking, identify patients at risk, and construct reports about individual surgeons. RESULTS: Following the inception of the Implant Registries, there was an observed (1) reduction in opioid utilization following orthopedic procedures, (2) reduction in use of bone morphogenic protein during lumbar fusion allowing for cost savings, (3) reduction in allograft for anterior cruciate ligament reconstruction and subsequent decrease in organizationwide revision rates, (4) cost savings through expansion of same-day discharge programs for joint arthroplasty, (5) increase in the use of cement fixation in the hemiarthroplasty treatment of hip fracture, and (6) organizationwide discontinuation of an endograft device associated with a higher risk for adverse outcomes following endovascular aortic aneurysm repair. CONCLUSION: The use of Implant Registries within our health system, along with clinical leadership and organizational commitment to a learning health system, was associated with improved quality and safety outcomes and reduced costs. The exact mechanisms by which such registries affect health outcomes and costs require further study.

Utilization of Total Joint Arthroplasty by Rural-Urban Designation in Patients With Osteoarthritis in a Universal Coverage System.

BACKGROUND: Utilization of total joint arthroplasty (TJA) is affected by differences linked to sex, race, and socioeconomic status; there is little information about how geographic variation contributes to these differences. We sought to determine whether discrepancies in TJA utilization exist in patients diagnosed with osteoarthritis (OA) based upon urban-rural designation in a universal coverage system. METHODS: We conducted a cohort study using data from a US-integrated healthcare system (2015 to 2019). Patients aged ≥50 years who had a diagnosis of hip or knee OA were included. Total hip arthroplasty and total knee arthroplasty utilization (in respective OA cohorts) was evaluated by urban-rural designation (urban, mid, and rural). Incidence rate ratios (IRRs) for urban-rural regions were modeled using multivariable Poisson regressions. RESULTS: The study cohort included 93,642 patients who have hip OA and 275,967 patients who had knee OA. In adjusted analysis, utilization of primary total hip arthroplasty was lower in patients living in urban areas (IRR = 0.87, 95% confidence interval = 0.81 to 0.94) compared to patients in rural regions. Similarly, total knee arthroplasty was used at a lower rate in urban areas (IRR = 0.88, 95% confidence interval = 0.82 to 0.95) compared with rural regions. We found no differences in the hip and knee groups within the mid-region. CONCLUSIONS: In hip and knee OA patients enrolled in a universal coverage system, we found patients living in urban areas had lower TJA utilization compared to patients living in rural areas. Further research is needed to determine how patient location contributes to differences in elective TJA utilization. LEVEL OF EVIDENCE: III.

Association Between Race/Ethnicity and 90-Day Emergency Department Visits in Patients Undergoing Elective Total Knee Arthroplasty or Total Hip Arthroplasty in a Universally Insured Population.

BACKGROUND: Research has identified disparities in returns to care by race/ethnicity following primary total joint arthroplasty. We sought to identify risk factors for 90-day emergency department (ED) returns following primary total knee arthroplasty (TKA) or total hip arthroplasty (THA) for these populations. METHODS: Black, Hispanic, and non-Hispanic White patients who underwent elective primary unilateral TKA and THA in an integrated US healthcare system were identified. Risk factors for 90-day postoperative ED visits including patient demographics, household income and education, comorbidities, preoperative healthcare utilization, and copay data were identified with multivariable logistic regression. RESULTS: Postoperative 90-day ED visits occurred in 13.3% of 79,565 TKA patients (17.2% Black; 14.9% Hispanic; 12.5% White) and 11.0% of THA patients (13.4% Black; 12.1% Hispanic; 10.7% White). Across racial/ethnic categories, patients who had an ED visit within 1 year of their TKA or THA date were more likely to have a 90-day ED return. Shared risk factors for TKA patients were chronic lung disease and outpatient utilization (25th and 75th percentile), while peripheral vascular disease was a shared risk factor for THA patients. Risk factors for multiple races of TKA and THA patients included depression, drug abuse, and psychosis. Prior copay for White (TKA) and Hispanic (TKA and THA) patients was protective, while preoperative primary care was protective for Black THA patients. CONCLUSION: Future strategies to reduce postoperative ED returns should include directed patient outreach for patients who had ED visits and mental health in the year prior to TKA and THA. LEVEL OF EVIDENCE: III.

Temporal Trends in Deep Surgical Site Infections After Six Orthopaedic Procedures Over a 12-year Period Within a US-based Healthcare System.

INTRODUCTION: Centers of excellence and bundled payment models have driven perioperative optimization and surgical site infection (SSI) prevention with decolonization protocols and antibiotic prophylaxis strategies. We sought to evaluate time trends in the incidence of deep SSI and its causative organisms after six orthopaedic procedures in a US-based integrated healthcare system. METHODS: We conducted a population-level time-trend study using data from Kaiser Permanente's orthopaedic registries. All patients who underwent primary anterior cruciate ligament reconstruction (ACLR), total knee arthroplasty (TKA), elective total hip arthroplasty (THA), hip fracture repair, shoulder arthroplasty, and spine surgery were identified (2009 to 2020). The annual incidence of 90-day deep SSI was identified according to the National Healthcare Safety Network/Centers for Disease Control and Prevention guidelines with manual chart validation for identified infections. Poisson regression was used to evaluate annual trends in SSI incidence with surgical year as the exposure of interest. Annual trends in overall incidence and organism-specific incidence were considered. RESULTS: The final study sample was composed of 465,797 primary orthopaedic procedures. Over the 12-year study period, a decreasing trend in deep SSI was observed for ACLR and hip fracture repair. Although there was variation in incidence rates for specific operative years for TKA, elective THA, shoulder arthroplasty, and spine surgery, no consistent decreasing trends over time were found. Decreasing rates of Staphylococcus aureus infections over time after hip fracture repair, shoulder arthroplasty, and spine surgery and decreasing trends in antibiotic resistance after elective THA and spine surgery were also observed. Increasing trends of polymicrobial infections were observed after TKA and Cutibacterium acnes after elective THA. CONCLUSIONS: The overall incidence of deep SSI after six orthopaedic procedures was rare. Decreasing SSI rates were observed for ACLR and hip fracture repair within our US-based healthcare system. Polymicrobial infections after TKA and Cutibacterium acnes after elective THA warrant closer surveillance. LEVEL OF EVIDENCE: IV.

Association Between Race/Ethnicity and Total Joint Arthroplasty Utilization in a Universally Insured Population.

INTRODUCTION: Previous studies have documented racial and ethnic disparities in total joint arthroplasty (TJA) utilization in the United States. A potential mediator of healthcare disparities is unequal access to care, and studies have suggested that disparities may be ameliorated in systems of universal access. The purpose of this study was to assess whether racial/ethnic disparities in TJA utilization persist in a universally insured population of patients enrolled in a managed healthcare system. METHODS: This retrospective cohort study used data from a US integrated healthcare system (2015 to 2019). Patients aged 50 years and older with a diagnosis of hip or knee osteoarthritis were included. The outcome of interest was utilization of primary total hip arthroplasty and/or total knee arthroplasty, and the exposure of interest was race/ethnicity. Incidence rate ratios (IRRs) were modeled using multivariable Poisson regression controlling for confounders. RESULTS: There were 99,548 patients in the hip analysis and 290,324 in the knee analysis. Overall, 10.2% of the patients were Black, 20.5% were Hispanic, 9.6% were Asian, and 59.7% were White. In the multivariable analysis, utilization of primary total hip arthroplasty was significantly lower for all minority groups including Black (IRR, 0.55, 95% confidence interval [CI], 0.52-0.57, P < 0.0001), Hispanic (IRR, 0.63, 95% CI, 0.60-0.66, P < 0.0001), and Asian (IRR, 0.64, 95% CI, 0.61-0.68, P < 0.0001). Similarly, utilization of primary total knee arthroplasty was significantly lower for all minority groups including Black (IRR, 0.52, 95% CI, 0.49-0.54, P < 0.0001), Hispanic (IRR, 0.72, 95% CI, 0.70-0.75, P < 0.0001), and Asian (IRR, 0.60, 95% CI, 0.57-0.63, P < 0.0001) (all in comparison with White as reference). CONCLUSIONS: In this study of TJA utilization in a universally insured population of patients enrolled in a managed healthcare system, disparities on the basis of race and ethnicity persisted. Additional research is required to determine the reasons for this finding and to identify interventions which could ameliorate these disparities.

Postoperative Acute Kidney Injury With Dual NSAID Use After Outpatient Primary Total Joint Arthroplasty.

BACKGROUND: NSAIDs have been shown to be highly effective analgesic agents in the postoperative period. NSAIDs do have several potential adverse effects, including kidney injury (AKI). Little is known about AKI in the outpatient total joint arthroplasty (TJA) setting, where patient labs are not closely monitored. The objective of this study was to evaluate the renal safety of combined use of ibuprofen for pain control and aspirin for deep vein thrombosis chemoprophylaxis after outpatient primary TJA. METHODS: Patients undergoing primary total hip or total knee arthroplasty between January 2020 and July 2020 at a single center were included for analysis. All included patients were discharged on a standard regimen including aspirin 81 mg twice a day and ibuprofen 600 mg three times a day. Patients were ordered a serum creatinine test at 2 and 4 weeks postoperatively. Patients with postoperative acute kidney injury were identified per Acute Kidney Injury Network criteria. RESULTS: Between January 23, 2020, and August 30, 2020, 113 patients were included in this study, of whom creatinine levels were measured in 103 patients (90.3%) at the 2-week postoperative time point, 58 patients (50.9%) at the 4-week time point, and 48 (42.1%) at combined 2- and 4-week time points. Three patients (2.9%) were found to have an AKI. CONCLUSION: This study found a rate of AKI of 2.9% with the use of dual NSAID therapy postoperatively after primary TJA. All cases occurred at 2 weeks postoperatively and saw spontaneous resolution.

Is There Harm in Debridement, Antibiotics, and Implant Retention Versus Two-Stage Revision in the Treatment of Periprosthetic Knee Infection? Experiences Within a Large US Health Care System.

BACKGROUND: When faced with a periprosthetic joint infection (PJI) following total knee arthroplasty, the treating surgeon must determine whether 2-stage revision or "liner exchange," aka debridement, antibiotics, exchange of the modular polyethylene liner, and retention of fixed implants (DAIR), offers the best balance of infection eradication versus treatment morbidity. We sought to determine septic re-revision risk following DAIR compared to initial 2-stage revision. METHODS: We conducted a cohort study using data from Kaiser Permanente's total joint replacement registry. Primary total knee arthroplasty patients who went on to have a PJI treated by DAIR or 2-stage revision were included (2005-2018). Propensity score-weighted Cox regression was used to evaluate risk for septic re-revision. RESULTS: In total, 1,410 PJIs were included, 1,000 (70.9%) treated with DAIR. Applying propensity score weights, patients undergoing DAIR had a higher risk for septic re-revision compared to initial 2-stage procedures (hazard ratio 3.09, 95% CI 2.22-4.42). Of DAIR procedures, 150 failed (15%) and went on to subsequent 2-stage revision (DAIR-F). When compared to patients undergoing an initial 2-stage revision, we failed to observe a difference in septic re-revision risk following DAIR-F (hazard ratio 1.11, 95% CI 0.58-2.12). CONCLUSION: Although DAIR had a higher risk of septic re-revision, we failed to observe a difference in risk following DAIR-F when compared to those who initially underwent 2-stage revision. Functional outcome, patient, and organism factors are important to consider when discussing PJI management options. LEVEL OF EVIDENCE: Level III.

Cause-Specific Stem Revision Risk in Primary Total Hip Arthroplasty Using Cemented vs Cementless Femoral Stem Fixation in a US Cohort.

BACKGROUND: We sought to evaluate the cause-specific revision risk following hybrid (cemented stem mated to a cementless acetabular implant) vs cementless total hip arthroplasty (THA) in a US cohort. METHODS: Primary elective THA for osteoarthritis was identified using Kaiser Permanente's Total Joint Replacement Registry (2001-2018). Multivariable Cox regression was used to evaluate cause-specific revision, including aseptic loosening, infection, instability, and periprosthetic fracture (PPF), for hybrid vs cementless THA. Analysis was stratified by age (<65, 65-74, and ≥75 years) and gender. RESULTS: The study cohort comprised 88,830 THAs, including 4539 (5.1%) hybrid THAs. In stratified analysis, hybrid THA had a higher revision risk for loosening in females in all 3 age subgroups. A lower risk of revision for PPF was observed following hybrid THA in females aged ≥75 years. For females ≥75 years, cementless THA had an excess PPF risk of 0.9% while hybrid THA had an excess loosening risk of 0.2%, translating to a theoretical prevention of 10 PPF revisions but a price of 3 loosening revisions per 1000 hybrid THAs. No difference in revision risk was observed in males. CONCLUSION: We observed differences in cause-specific revision risks by method of stem fixation which depended upon patient age and gender. Although the trend toward all cementless fixation continue, there may be a role for hybrid fixation in females ≥75 years to mitigate risk for revision due to PPF at the potential cost of a slight increase in longer term aseptic loosening. LEVEL OF EVIDENCE: Level III.

Revision Risk in a Cohort of US Patients Younger Than 55 Undergoing Primary Elective Total Hip Arthroplasty.

BACKGROUND: As indications for elective total hip arthroplasty (THA) expand to younger patients, we sought to (1) compare revision risk following primary elective THA in patients <55 years at the time of their THA to patients aged ≥65 years and (2) identify specific risk factors for revision in patients <55 years. METHODS: A Kaiser Permanente's total joint replacement registry was used to conduct a cohort study including primary elective THA patients aged ≥18 (2001-2018). In total, 11,671 patients <55 years and 53,106 patients ≥65 years were included. Multiple Cox regression was used to evaluate cause-specific revision risk, including septic revision, aseptic loosening, instability, and periprosthetic fracture. Stepwise Cox regression was used to identify patient and surgical factors associated with cause-specific revision in patients <55 years. RESULTS: Patients <55 years had a higher risk of septic revision (hazard ratio [HR] = 1.30, 95% confidence interval [CI] = 1.02-1.66), aseptic loosening (HR = 2.60, 95% CI = 1.99-3.40), and instability (HR = 1.35, 95% CI = 1.09-1.68), but a lower risk of revision for periprosthetic fracture (HR = 0.36, 95% CI = 0.22-0.59) compared to patients aged ≥65 years. In the <55 age group, risk factors for septic revision included higher body mass index, drug abuse, and liver disease. Hypertension, anterior approach, and ceramic-on-ceramic were associated with aseptic loosening. White race, American Society of Anesthesiologists classification ≥3, smoker, paralysis, posterior approach, ceramic-on-ceramic, and smaller head diameter were associated with instability. CONCLUSION: Identified risk factors varied depending on the cause for revision. Although septic revisions were related to patient characteristics, more modifiable factors, such as implant or surgical approach, were associated with revision due to aseptic loosening and instability. LEVEL OF EVIDENCE: III.

Association Between Same-Day Discharge Total Joint Arthroplasty and Risk of 90-Day Adverse Events in Patients with ASA Classification of ≥3.

BACKGROUND: Although safety in same-day discharge total joint arthroplasty (TJA) has been reported, findings are limited to healthier patients, specific surgeons, and/or specific institutions. Indications for same-day discharge TJA have expanded to include patients with multiple comorbidities; however, safety in this specific patient population remains unknown. Therefore, we sought to compare the risk of 90-day adverse events in higher-risk patients undergoing same-day discharge versus inpatient TJA. METHODS: The Kaiser Permanente Total Joint Replacement Registry was utilized to conduct a cohort study. All patients with an American Society of Anesthesiologists (ASA) classification of ≥3 who underwent primary elective TJA for osteoarthritis from 2017 through 2018 were identified. The risk of 90-day adverse events (i.e., emergency department visits, unplanned readmissions, complications, and mortality) was evaluated with use of propensity score-weighted Cox proportional hazard regression including noninferiority testing with a margin of 1.10. RESULTS: The cohort included a total of 5,250 patients who underwent total hip arthroplasty and 9,752 patients who underwent total knee arthroplasty, of whom 1,742 (33.2%) and 3,283 (33.7%) had same-day discharge, respectively. Same-day discharge hip arthroplasty was noninferior to an inpatient stay in terms of emergency department visits (hazard ratio [HR], 0.73; 1-sided HR 95% upper bound [UB], 0.84), readmissions (HR, 0.47; 95% UB, 0.61), and complications (HR, 0.63; 95% UB, 0.75); we did not have evidence of noninferiority for mortality (HR, 0.84; 95% UB, 1.97). Same-day discharge knee arthroplasty was noninferior to an inpatient stay in terms of emergency department visits (HR, 0.79; 95% UB, 0.87), readmission (HR, 0.80; 95% UB, 0.95), complications (HR, 0.72; 95% UB, 0.82), and mortality (HR, 0.53; 95% UB, 1.03). CONCLUSIONS: We found that same-day discharge TJA did not increase the risk of emergency department visits, unplanned readmissions, and complications compared with an inpatient stay for higher-risk patients, suggesting that it is possible to expand indications for same-day discharge TJA in the hospital setting while maintaining safety. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Frequency and Timing of Complications and Catastrophic Events After Same-Day Discharge Compared With Inpatient Total Hip Arthroplasty.

BACKGROUND: Same-day discharge total hip arthroplasty (THA) has grown in utilization although concerns exist regarding early complications and catastrophic events. We sought to compare the risk of complications and catastrophic events for same-day and inpatient stay THA. METHODS: A cohort study was conducted using Kaiser Permanente's total joint replacement registry. Primary elective THA were identified (2017-2018). Propensity score-weighted Cox proportional hazards regression was used to evaluate risk for 90-day incident events, including emergency department (ED) visit, unplanned readmission, cardiac complication, deep infection, venous thromboembolism (VTE), and mortality, by in-hospital length of stay: same-day vs 1-2-night inpatient stay. RESULTS: The study sample comprised 13,646 THA, 6033 (44.1%) with a same-day discharge. Median days-to-events for same-day vs inpatient was 11 vs 12 for ED visit, 23 vs 20 for readmission, 38 vs 12 for cardiac complication, 28 vs 24 for deep infection, 14.5 vs 23.5 for VTE, and 7 vs 35.5 for mortality. In propensity score-weighted models, same-day discharge THA had a lower risk for 90-day ED visit (HR = 0.82, 95% CI = 0.72-0.94), readmission (HR = 0.75, 95% CI = 0.61-0.92), and cardiac complication (HR = 0.60, 95% CI = 0.47-0.76), compared with inpatient stay THA; no difference was observed for deep infection (HR = 1.59, 95% CI = 0.81-3.12), VTE (HR = 0.90, 95% CI = 0.52-1.58), or mortality (HR = 0.81, 95% CI = 0.27-2.40). CONCLUSION: We observed a lower or no difference in risk for complications and catastrophic events after same-day THA than an inpatient stay. Catastrophic events were more likely to occur early in the 90-day period, but an inpatient stay did not preclude events.

Modular Tibial Stem Use and Risk of Revision for Aseptic Loosening in Cemented Primary Total Knee Arthroplasty.

BACKGROUND: Modular tibial stem extensions in total knee arthroplasty (TKA) are designed to reduce the risk of aseptic loosening of the tibial base plate. However, these implants add significant cost and an evaluation of their effectiveness in reducing this risk of loosening has not been studied in a large cohort. We sought to evaluate modular tibial stem utilization in primary TKA. METHODS: We conducted a cohort study using our integrated healthcare system's Total Joint Replacement Registry. Patients who underwent cemented primary TKA were identified (2009-2019). Propensity scores were used to 1:1 match patients without to those with a stem extension. Cox proportional-hazards regression was used to evaluate the risk for revision due to aseptic loosening. RESULTS: Ten thousand four hundred seventy six TKA with a modular tibial stem were matched to 10,476 TKA without a tibial stem. Stem utilization associated with a lower risk of revision for loosening across all postoperative follow-up (hazard ratio = 0.38, 95% confidence interval = 0.17-0.85). CONCLUSION: In a matched cohort study, we observed presence of a stem extension was associated with a lower risk of revision for aseptic loosening. Further study to identify specific risk factors for aseptic loosening and confirm the findings presented here are warranted. LEVEL OF EVIDENCE: Level III.

Risk Factors for Conversion of Hip Arthroscopy to Total Hip Arthroplasty: A Large Closed-Cohort Study.

PURPOSE: To evaluate risk factors for conversion of hip arthroscopy to total hip arthroplasty (THA) within 2 years in a closed patient cohort. METHODS: This study was a case series of consecutive hip arthroscopy procedures from September 2008 to November 2018 in the electronic medical record of Kaiser Permanente Northern California. Patients were included with minimum 2-year follow-up or if they had conversion to THA within 2 years (the primary outcome) regardless of follow-up time. Patient characteristics at the time of the index arthroscopy were extracted; characteristics of patients who experienced the outcome event versus those who did not were compared by use of multivariable logistic regression models and receiver operating characteristic (ROC) curves. RESULTS: The mean follow-up time was 4.9 years (median 4.6, range 0.6 to 11.6). The mean age was 37.2 years (range 10 to 88), and 57% were female. During the follow-up period, 82 patients underwent a THA within 2 years of their arthroscopies (5.3%, 95% confidence interval 4.3% to 6.5%) after a median time of 9 months (interquartile range 5.9 to 14.4) after the initial arthroscopy. Increasing age was highly predictive of early THA conversion (area under the ROC curve = 0.78, P < .001). Although other predictors showed significant bivariable associations with early failure, body mass index (BMI), race, sex, and prior arthroscopy did not add meaningful independent predictive information. CONCLUSIONS: The risk of conversion to THA within 2 years after hip arthroscopy increased substantially with patient age at the time of the procedure. BMI, race, sex, and prior arthroscopy were not important independent predictors of conversion beyond the information contained in patient age. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Commercially Prepared Antibiotic-Loaded Bone Cement and Infection Risk Following Cemented Primary Total Knee Arthroplasty.

BACKGROUND: The efficacy of commercially available antibiotic-loaded bone cement (ABC) in preventing infection in total knee arthroplasty (TKA) is unclear. We sought to determine the effectiveness of commercially available ABC in reducing the risk of infection following TKA, both overall and among 3 subgroups of patients with a higher risk of infection (diabetes, body mass index ≥35 kg/m, and American Society of Anesthesiologists classification ≥3), and to evaluate the association between the use of ABC and the risks of aseptic revision and revision for aseptic loosening. METHODS: The Kaiser Permanente Total Joint Replacement Registry was utilized to evaluate 87,018 primary cemented TKAs performed from 2008 to 2016. The primary outcome was time to infection (90-day deep infection or septic revision). Reduced infection risk with ABC relative to regular cement was tested with use of propensity-score-weighted Cox proportional-hazards models with superiority and noninferiority testing. All analyses were replicated for each of the 3 high-risk subgroups. For the secondary revision outcomes, propensity-score-weighted Cox proportional-hazards models were utilized. RESULTS: Regular cement was found to be noninferior to ABC with respect to risk infection (hazard ratio [HR], 1.14; 95% confidence interval [CI], 0.93 to 1.40) and cost across all TKA patients. However, a lower risk of infection was observed with ABC among TKA patients with diabetes (HR, 0.72; 95% CI, 0.52 to 0.99). There was no evidence of a difference in risk of revision for ABC compared with regular cement. CONCLUSIONS: We found that the additional cost associated with the use of commercially prepared ABC in primary TKA was not justified in all patients; however, the risk of reduction was lower among patients with diabetes who received ABC. Further study is warranted to identify the efficacy of ABC among other high-risk populations. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The Association of Race/Ethnicity and Total Knee Arthroplasty Outcomes in a Universally Insured Population.

BACKGROUND: Prior studies have documented racial/ethnic disparities in the United States for total knee arthroplasty (TKA) outcomes. One factor cited as a potential mediator is unequal access to care. We sought to assess whether racial/ethnic disparities persist in a universally insured TKA population. METHODS: A US integrated health system's total joint replacement registry was used to identify elective primary TKA (2000-2016). Racial/ethnic differences in revision and 90-day postoperative events (readmission, emergency department [ED] visit, infection, venous thromboembolism, and mortality) were analyzed using Cox proportional hazard and logistic regression with adjustment for confounders. RESULTS: Of 129,402 TKA, 68.8% were white, 16.2% were Hispanic, 8.4% were black, and 6.6% were Asian. Compared to white patients, Hispanic patients had lower risks of septic revision (hazard ratio [HR] = 0.69, 95% confidence interval [CI] = 0.57-0.83) and infection (odds ratio [OR] = 0.42, 95% CI = 0.30-0.59), but a higher likelihood of ED visit (OR = 1.28, 95% CI = 1.22-1.34). Black patients had higher risks of aseptic revision (HR = 1.61, 95% CI = 1.42-1.83), readmission (OR = 1.13, 95% CI = 1.02-1.24), and ED visit (OR = 1.31, 95% CI = 1.23-1.39). Asian patients had lower risks of aseptic revision (HR = 0.67, 95% CI = 0.54-0.83), septic revision (HR = 0.78, 95% CI = 0.60-0.99), readmission (OR = 0.89, 95% CI = 0.79-1.00), and venous thromboembolism (OR = 0.59, 95% CI = 0.45-0.78). CONCLUSION: We observed differences in TKA outcome, even within a universally insured population. While lower risks in some outcomes were observed for Asian and Hispanic patients, the higher risks of aseptic revision and readmission for black patients and ED visit for black and Hispanic patients warrant further research to determine reasons for these findings to mitigate disparities. LEVEL OF EVIDENCE: Level III.

A Comparison of Risk of Dislocation and Cause-Specific Revision Between Direct Anterior and Posterior Approach Following Elective Cementless Total Hip Arthroplasty.

BACKGROUND: Use of the direct anterior approach (DAA) for total hip arthroplasty (THA) has increased over the last decade. We sought to investigate whether (1) a difference exists in dislocation risk for DAA compared with posterior THA, (2) a difference exists in risk for specific revision reasons, and (3) the likelihood of adverse 90-day postoperative events differs. METHODS: We conducted a cohort study using data from Kaiser Permanente's Total Joint Replacement Registry. Patients aged ≥18 years who underwent primary cementless THA for osteoarthritis with a highly cross-linked polyethylene liner were included (2009-2017). Multivariable Cox proportional hazards regression was used to evaluate dislocation and cause-specific revision risks, and multivariable logistic regression was used to evaluate 90-day emergency department visits, 90-day unplanned readmissions, and 90-day complications (including deep infection, deep vein thrombosis, and pulmonary embolism). RESULTS: Of 38,399 primary THA, 6428 (16.7%) were DAA. All-cause revision at 2-years follow-up was 1.78% (95% confidence interval [CI] = 1.46-2.17) for DAA and 2.28% (95% CI = 2.11-2.45) for posterior. After adjusting for covariates, DAA had a lower risk of dislocation (hazard ratio [HR] = 0.39, 95% CI = 0.29-0.53), revision for instability (HR = 0.33, 95% CI = 0.18-0.58), revision for periprosthetic fracture (HR = 0.57, 95% CI = 0.34-0.96), and readmission (odds ratio = 0.82, 95% CI = 0.67-0.99) compared with posterior approach but a higher risk of revision for aseptic loosening (HR = 2.26, 95% CI = 1.35-3.79). CONCLUSION: While the DAA associated with lower risks of dislocation and revision for instability and periprosthetic fracture, it is associated with a higher revision risk for aseptic loosening. Surgeons should discuss these risks with their patients.

Lumbar Spine Fusion Patients See Similar Improvements in Physical Activity Level to Non-Spine Fusion Patients Following Total Hip Arthroplasty.

BACKGROUND: The impact of prior lumbar spinal fusion on the change in physical activity level following total hip arthroplasty (THA) has not been thoroughly examined. Therefore, we sought to compare the change in physical activity level following THA for patients with and without a history of lumbar spine fusion. METHODS: Patients who underwent primary elective THA were identified using an integrated healthcare system's Total Joint Replacement Registry (2010-2013). Prior lumbar spine fusion was identified using the healthcare system's Spine Registry. Physical activity was self-reported by patients and measured in min/wk. Generalized linear models were used to evaluate the association between prior spine fusion and the change in physical activity from 1 year pre-THA to 1-2 years post-THA. RESULTS: Of 11,416 THAs, 90 (0.8%) had a history of lumbar spinal fusion. Patients with a prior lumbar fusion had a median physical activity level of 28 min/wk prior to THA compared to 45 min/wk in the patients with no history of lumbar spinal fusion. One year after THA, patients with a history of lumbar spinal fusion reported a median of 120 min/wk of physical activity compared to 150 min/wk for patients without a history of lumbar spinal fusion. The difference in physical activity level change between groups was not statistically significant (estimate = -23.1, 95% confidence interval -62.1 to 15.9, P = .246). CONCLUSION: Patients with prior lumbar fusion were found to have lower self-reported physical activity levels than patients without spine fusion both before and after THA surgery. However, both groups saw the same degree of improvement in physical activity level following THA. These findings may help in counseling patients who have had a prior lumbar spine fusion and in setting appropriate expectations prior to THA.

Association of Race and Ethnicity with Total Hip Arthroplasty Outcomes in a Universally Insured Population.

BACKGROUND: Prior studies have documented racial and ethnic disparities in total hip arthroplasty (THA) outcomes in the U.S. The purpose of this study was to assess whether racial/ethnic disparities in THA outcomes persist in a universally insured population of patients enrolled in an integrated health-care system. METHODS: A U.S. health-care system total joint replacement registry was used to identify patients who underwent elective primary THA between 2001 and 2016. Data on patient demographics, surgical procedures, implant characteristics, and outcomes were obtained from the registry. The outcomes analyzed were lifetime revision (all-cause, aseptic, and septic) and 90-day postoperative events (infection, venous thromboembolism, emergency department [ED] visits, readmission, and mortality). Racial/ethnic differences in outcomes were analyzed with use of multiple regression with adjustment for socioeconomic status and other potential confounders. RESULTS: Of 72,755 patients in the study, 79.1% were white, 8.2% were black, 8.5% were Hispanic, and 4.2% were Asian. Compared with white patients, lifetime all-cause revision was lower for black (adjusted hazard ratio [HR], 0.79; 95% confidence interval [CI], 0.66 to 0.94; p = 0.007), Hispanic (adjusted HR, 0.73; 95% CI, 0.61 to 0.87; p = 0.002), and Asian (adjusted HR, 0.49; 95% CI, 0.37 to 0.66; p < 0.001) patients. Ninety-day ED visits were more common among black (adjusted odds ratio [OR], 1.15; 95% CI, 1.05 to 1.25; p = 0.002) and Hispanic patients (adjusted OR, 1.18; 95% CI, 1.08 to 1.28; p < 0.001). For all other postoperative events, minority patients had similar or lower rates compared with white patients. CONCLUSIONS: In contrast to prior research, we found that minority patients enrolled in a managed health-care system had rates of lifetime reoperation and 90-day postoperative events that were generally similar to or lower than those of white patients, findings that may be related to the equal access and/or standardized protocols associated with treatment in the managed care system. However, black and Hispanic patients still had higher rates of 90-day ED visits. Further research is required to determine the reasons for this finding and to identify interventions that could reduce unnecessary ED visits. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Impact of payer type on resource utilization, outcomes and access to care in total hip arthroplasty.

The purpose of this study was to determine if Medicaid patients undergoing a primary total hip arthroplasty differed from Medicare and commercial-payer patients with respect to baseline demographic characteristics, social history, clinical outcomes, and resource utilization. A retrospective review of 224 subjects who received a primary total hip arthroplasty at a single institution was conducted and stratified by insurance type. Baseline clinical and demographic information and functional outcomes were compared between Medicaid, Medicare, and commercial-payer patients. Medicaid patients had lower preoperative (P < .0001) and postoperative (P < .0001) Harris Hip Scores when compared with patients who have Medicare or commercial insurance. Medicaid patients also traveled twice as far to receive treatment (66.0 vs 38.3 miles). Decreased access to health care and increased time to presentation may account for the decreased functional scores and poorer clinical outcomes observed in Medicaid patients when compared with Medicare and commercially insured patients.

Discography-induced acute lumbar disc herniation: a report of five cases.

The reported complication rate of provocative lumbar discography is low, ranging from 0-2.5%. We report five cases of acute lumbar disc herniation precipitated by discography, a previously unreported complication. The cases reported comprise of four men and one woman with ages ranging from 23-45 years. All developed an acute exacerbation of radicular leg pain following multilevel provocative lumbar discography. One patient developed an acute foot drop. Comparison of lumbar MRI scans before and after discography demonstrated either a new herniated disc fragment or an increase in size of a preexisting herniation in all cases. On review of each discogram study and pre-discogram MRI an annular tear or small disc herniation was noted in all cases. In each case the patients' symptoms failed to resolve necessitating surgical intervention in all cases. In conclusion, annular deficiency is an obvious predisposing factor to discogram related disc herniation. New onset or a persistent exacerbation of radicular symptoms following provocative discography merits further investigation.