Arthrodesis Versus Trapeziectomy for Thumb Carpometacarpal Joint Arthritis with Metacarpophalangeal Joint Hyperextension.

Abstract

Thumb carpometacarpal (CMC) joint arthritis often presents with metacarpophalangeal (MCP) joint hyperextension. Although CMC joint arthrodesis and trapeziectomy are established treatments, their effects on MCP joint hyperextension and functional outcomes stratified by MCP joint status remain unclear. We assessed correction of MCP joint hyperextension and functional improvement according to preoperative MCP joint status after CMC joint arthrodesis or trapeziectomy and compared outcomes between procedures in patients with preoperative MCP joint hyperextension. Patients with CMC joint arthritis who underwent arthrodesis or trapeziectomy with suspensionplasty between 2012 and 2024 were retrospectively reviewed. Radiographic MCP joint and CMC joint angles and functional outcomes, including grip strength, key pinch strength, Kapandji score, visual analog scale for pain, and Quick Disabilities of the Arm, Shoulder, and Hand, were evaluated. Thumbs were categorized into preoperative MCP joint hyperextension (< -20°) and nonhyperextension (≥ -20°) groups. Changes from preoperative assessment to final follow-up were assessed within each group for each surgical procedure, and outcomes were compared between procedures in the MCP joint hyperextension subgroup. Eighty-four thumbs (arthrodesis: 42 and trapeziectomy: 42) were analyzed with a mean follow-up of 28 ± 19 months. Arthrodesis corrected MCP joint hyperextension by addressing CMC joint flexion deformity, while maintaining thumb opposition. Trapeziectomy did not reliably correct MCP joint hyperextension and, in the MCP joint nonhyperextension group, increased MCP joint extension. Functional improvement was observed in all subgroups except the trapeziectomy group with MCP joint hyperextension, which showed no notable improvement in grip or pinch strength. In the MCP joint hyperextension group, unadjusted comparisons demonstrated greater final pinch strength after arthrodesis and no reoperations after trapeziectomy, with comparable functional scores. After multivariable adjustment, surgical procedure was not independently associated with final pinch strength. Arthrodesis corrected MCP joint hyperextension, whereas trapeziectomy did not. For CMC joint arthritis with MCP joint hyperextension, decision making between arthrodesis and trapeziectomy should balance alignment correction, anticipated strength, and reoperation risk, guided by patients' priorities and expectations. Therapeutic III.