The Impact of Surgeon Volume on Unicompartmental Knee Arthroplasty Survivorship: A Michigan Arthroplasty Registry Collaborative Quality Initiative Database Analysis.

ABSTRACT

BACKGROUND: The utilization of unicompartmental knee arthroplasty (UKA) has remained low when compared to total knee arthroplasty (TKA), possibly due to higher rates of revision and reoperation. This study aimed to quantify surgeon UKA case-volumes and measure the effect of surgeon volume on early revision. We hypothesized that surgeons who have high case volumes would have lower revision rates compared to medium- and low-volume surgeons. METHODS: Primary UKAs were performed between February 2012 and November 2021, and associated revisions were identified utilizing the Michigan Arthroplasty Registry Collaborative Quality Initiative. Surgeon information, including total cases and annual UKA volume, was collected. Case volume per year was stratified as High (≥ 35 cases per year), Medium (15 to 34 cases per year), and low (< 15 cases per year). RESULTS: There were a total of 15,542 UKAs performed. Of these, 701 (4.5%) were revised, and 412 (58.8%) revisions occurred within 2 years. Of the 287 surgeons who performed an UKA in the registry, 237 (82.6%) were low-volume surgeons, 36 (12.5%) were medium-volume, and 14 (4.9%) were high-volume. High-volume surgeons were more likely to operate on older patients (P < 0.01), Medicare patients (P < 0.01), and patients who had American Society of Anesthesiologists scores of III and IV (P < 0.01). High-volume surgeons had significantly lower 5-year revision rates compared to medium and low-volume surgeons (high 4.3% (95% confidence interval 3.7 to 4.9), medium 5.2% (4.4 to 6.1), low 7.2% (6.4 to 8.0); P < 0.001). In comparison, the 5-year revision rate for TKA in Michigan was 3.0% (95% confidence interval 2.9 to 3.1). CONCLUSIONS: When UKAs were performed by high-volume surgeons in the state of Michigan, there was better survivorship when compared to low-and medium-volume surgeons. High-volume surgeons were more likely to perform UKA on older patients, Medicare patients, and patients who had American Society of Anesthesiologists scores of III and IV. The revision rate for the high-volume surgeons still exceeded the 5-year revision rate for TKA in Michigan.