Learning Curve Analysis of Dual-Mobility Trapeziometacarpal Arthroplasty: A Single-Surgeon Series With 2-Year Follow-up.

PURPOSE: To evaluate the learning curve of dual-mobility trapeziometacarpal arthroplasty using cumulative sum (CUSUM) analysis based on surgical time and clinical outcomes (complications and revisions) and report 2-year outcomes. METHODS: This prospective single-surgeon case series included patients undergoing dual-mobility trapeziometacarpal joint arthroplasty between September 2018 and January 2023. Of 125 arthroplasties in 109 patients, 12 cases with concomitant procedures were excluded, leaving 113 arthroplasties in 99 patients for analysis. Consecutive cases were analyzed using CUSUM analysis based on surgical time and outcome-based end points, including complications and revisions. Clinical outcomes included pain; Disabilities of the Arm, Shoulder and Hand score; key pinch strength; range of motion; and satisfaction. Reoperations and revision procedures were recorded. RESULTS: Mean patient age was 60 ± 9 years, and 81% were women. The median surgical time was 51 minutes (IQR 18). The surgical time CUSUM analysis peaked at case 28, indicating stabilization of surgical efficiency. All clinical outcomes showed significant postoperative improvement (P ≤ .001). Thirty-one complications (27%) were recorded; most were tendon-related or soft tissue-related. Eight (7%) were classified as attributable to suboptimal surgical technique. Eleven reoperations (10%) and four revision surgeries (4%) were performed. Outcome-based CUSUM analyses showed threshold crossings for overall complications and the subgroup of complications attributable to suboptimal surgical technique, whereas revision procedures remained within acceptable limits. Kaplan-Meier analysis demonstrated revision-free survival at 2 years of 0.973 (95% CI, 0.943-1.000). CONCLUSIONS: CUSUM analysis showed that surgical efficiency stabilized after approximately 28 cases; however, complications, including those related to suboptimal technique, persisted throughout the series and exceeded predefined thresholds. Thus, improved efficiency does not equate to technical mastery. Although 2-year outcomes and implant survival were favorable, these findings must be balanced against the observed complication burden. Although tendon-related complications are generally manageable, technique-related complications may be reduced through structured training and meticulous surgical execution. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.