Callaghan, John J

Background: Traditional Medicare (TM) claims data are widely used by researchers and registries to report survivorship following total knee arthroplasty (TKA). The purpose of the present study was to investigate whether the mass exodus of patients from TM to Medicare Advantage (MA) has compromised the fidelity of TM data. Methods: We identified 11,717 Medicare-eligible patients (15,282 knees) who had undergone primary TKA from 2000 to 2020 at a single institution. Insurance type was analyzed, and 84% of TKAs were covered by TM. The rates of survivorship free from revision or reoperation were calculated for patients with TM coverage. The same survivorship end points were recalculated after censoring of patients who transitioned to MA after primary TKA, thereby modeling the impact of losing patients from the TM dataset. Differences in survivorship were compared. The mean duration of follow-up was 10 years. Results: From 2000 to 2020, there was a decrease in TM insurance (from 94% to 68%) and a corresponding increase in MA insurance (from 0% to 19%) among patients undergoing TKA. Following TKA, 25% of patients with TM coverage switched to MA. For patients with TM at the time of surgery, the 15-year rates of survivorship free from any reoperation or revision were 90% and 96%, respectively. When patients were censored upon transition from TM to MA, the 15-year rates of survivorship free from any reoperation (92% versus 90%; hazard ratio [HR] = 1.2; p = 0.001) or any revision (97% versus 96%; HR = 1.3; p = 0.002) were significantly higher. Conclusions: One in 4 patients left TM for MA after primary TKA, effectively making them lost to follow-up within TM datasets. The mass exodus of patients out of TM resulted in falsely elevated estimates of survivorship free from reoperation and from revision, with increasing divergence in survivorship over time, when MA data were excluded. As MA continues to grow, efforts to incorporate these data will become increasingly important. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Background: Medicare Advantage (MA) plans are popular among Medicare-eligible patients, but little is known about MA in lower-extremity total joint arthroplasty (TJA). The purpose of this study was to describe trends in MA utilization and analyze differences in patient characteristics and postoperative outcomes between patients undergoing primary TJA using traditional Medicare (TM) or MA plans. Methods: Patients ≥65 years of age who underwent primary total knee or total hip arthroplasty were identified using the Premier Healthcare Database. Patients were categorized into TM and MA cohorts. Data from 2004 to 2020 were used to describe trends in insurance coverage. Data from 2015 to 2020 were used to identify differences in patient characteristics and postoperative complications using ICD-10 codes. Multivariate analyses were performed using 2015 to 2020 data to account for potential confounders. Results: From 2004 to 2020, the proportion of patients with MA increased from 7.9% to 34.4%, while those with TM decreased from 83.7% to 54.0%. Of the 697,317 patients who underwent primary elective TJA from 2015 to 2020, 471,439 (67.6%) had TM coverage and 225,878 (32.4%) had MA coverage. The cohorts were similar in terms of age and sex. However, a higher proportion of Black patients (8.29% compared with 4.62%; p < 0.001) and a lower proportion of White patients (84.0% compared with 89.2%; p < 0.001) were enrolled in MA compared with TM. After controlling for confounders, patients with MA had higher odds of surgical site infection (adjusted odds ratio [aOR]: 1.15; 95% confidence interval [CI]: 1.04 to 1.47; p = 0.031), periprosthetic joint infection (aOR: 1.10; 95% CI: 1.03 to 1.18; p = 0.006), stroke (aOR: 1.15; 95% CI: 1.02 to 1.31; p = 0.026), and acute kidney injury (aOR: 1.08; 95% CI: 1.04 to 1.11; p < 0.001), but lower odds of urinary tract infection (aOR: 0.94; 95% CI: 0.90 to 0.98; p = 0.003). Conclusions: From 2004 to 2020, the number of patients utilizing MA increased markedly such that 1 in 3 were covered by MA in 2020. From 2015 to 2020, patients who were non-White were more likely to have MA than TM, and the MA group had a higher rate of several postoperative complications compared with the TM group. As TM claims data inform health-care policy and clinical decisions, this change portends future challenges, including limitations in arthroplasty registry research, an increase in the administrative burden of surgeons, and a potential worsening of social disparities in health care.