Pyrolytic Carbon Arthroplasty versus Suspensionplasty for Trapezial-Metacarpal Arthritis

Purpose This study aims to compare outcomes after pyrolytic carbon implant hemiarthroplasty (PH) versus Thompson suspensionplasty (TS) for trapezial-metacarpal (TM) arthritis. Patients and Methods There were 87 arthritic TM joints in 71 patients treated with PH (n = 47 joints, 37 patients) or TS (n = 40 joints, 34 patients). Patients had significantly longer follow-up in the TS group (86.9 months, 25th-75th percentile = 55.6-103.8) versus the PH group (38.4 months, 25th-75th percentile = 23.2-65.8, p < 0.001). Results PH patients maintained higher final grip strength (p = 0.03) and apposition pinch strength (p = 0.01) compared with TS patients. Nelson scores were significantly higher among patients undergoing PH (mean = 50.4, standard deviation [SD] = 24.5) compared with TS (mean = 36.8, SD = 12.5, p < 0.01). There was a significantly higher proportion of complications (p < 0.01), reoperations (p < 0.01), and joint revision surgery (p < 0.01) in patients undergoing PH compared with TS. Controlling for age and sex, there was a 72.8% lower risk of complications (p = 0.02), 87.7% lower risk of reoperations (p = 0.01), and 87.2% lower risk of joint revision surgery (p < 0.01) among patients undergoing TS compared with PH. There was a shorter time to first complication (p < 0.01), reoperation (p < 0.02), and joint revision (p < 0.01) in those undergoing PH compared with TS. Conclusion Both cohorts exhibited functional range of motion and pinch and grip strengths postoperatively, and those undergoing PH began with and maintained higher grip and pinch strength at final follow-up. Those undergoing PH had significantly increased risk of complications, reoperations, and joint revision surgery. Most complications in patients undergoing PH were related to suspected development of scaphotrapezotrapezoidal (STT) arthritis postoperatively. We thus recommend careful evaluation of possible STT arthritis when considering PH arthroplasty. Level of Evidence Level III.