Long-Term Survival and Functional Outcomes of Scaphotrapeziotrapezoid Arthroplasty

Abstract

Abstract Scaphotrapeziotrapezoid (STT) osteoarthritis is the second most common cause of wrist degeneration. Traditional surgical options, such as STT arthrodesis or distal scaphoid resection, may alter carpal kinematics or be associated with complications. Resurfacing arthroplasty with scaphoid anchorage has emerged as an alternative aimed at preserving mobility while reducing pain. The purpose of this study was to evaluate long-term prosthetic survival and clinical outcomes following STT arthroplasty with a scaphoid-anchored resurfacing implant. A prospective longitudinal study was conducted including 21 consecutive patients with isolated symptomatic STT osteoarthritis treated with the same resurfacing implant between 2013 and 2016. All procedures were performed by the same hand surgery team. Pain, thumb mobility, grip and pinch strength, and upper-extremity function were assessed using validated instruments. Prosthetic survival was evaluated at a minimum follow-up of 100 months. Radiographic follow-up assessed implant integrity, carpal stability, and degenerative changes in adjacent joints. Mean follow-up was 131.2 months. Pain significantly improved from 8.48 ± 0.93 to 2.00 ± 1.27 (mean difference 6.48), exceeding the minimal clinically important difference. Kapandji mobility remained stable (9.24 ± 0.44). The Disabilities of the Arm, Shoulder and Hand (DASH) score at 10 years was 23.55 ± 10.72. Grip and pinch strength were slightly lower in the operated hand. Ten-year prosthetic survival was 85.7%, with three cases of loosening requiring implant removal. An exploratory subgroup analysis suggested a higher rate of prosthetic failure in patients with concomitant mild trapeziometacarpal osteoarthritis. No progression of carpal instability or of osteoarthritis in joints adjacent to the STT articulation was observed over time. Scaphoid-anchored resurfacing STT arthroplasty provides significant and sustained pain relief, preserves mobility, and demonstrates adequate long-term prosthetic survival. It is a valid surgical option for isolated STT osteoarthritis in appropriately selected patients. No progression of carpal instability or osteoarthritis in joints adjacent to the STT articulation was observed over time. IV, therapeutic study.