Volume and Outcomes of Joint Arthroplasty.

<bold>Background: </bold>Joint arthroplasties are among the most commonly performed elective surgeries in the United States. Surgical outcomes are known to improve with volume but it is unclear whether this has led to consolidation among elective surgeries. We examined trends in volumes per surgeon and hospital to assess whether the known volume-outcome relationship has led to consolidation in elective joint arthroplasty and to determine if there exist volume thresholds above which outcomes do not change.<bold>Methods: </bold>Among Medicare beneficiaries who underwent either total knee or total hip arthroplasty from 2009 through 2015, we described volume trends and used mixed-effect models to relate annual surgeon and hospital volumes with 30-day complications or mortality. We tested for optimal volume cut points at both the hospital and surgeon level.<bold>Results: </bold>Adjusted annual complication rates were inversely associated with volume for both procedures at both the surgeon level and hospital level, but there was minimal consolidation between 2009 and 2015. Complications no longer declined after volumes of each case exceeded 260 per year. The vast majority of cases (around 93% of hip and 88% of knee arthroplasties) were performed by surgeons operating at suboptimal volumes.<bold>Conclusion: </bold>More than 2 decades after the volume-outcome relationship was established for joint arthroplasty, many cases continue to be performed by low-volume surgeons, with far more cases performed by surgeons operating at suboptimal volumes. Further improvement could be expected through consolidation at both the hospital and surgeon level, with a target of at least 260 cases per surgeon annually for each operation. Payers seem best-equipped to drive consolidation. [ABSTRACT FROM AUTHOR]