Comparison of Thumb Metacarpophalangeal Arthrodesis to Volar Plate Capsulodesis for Metacarpophalangeal Hyperextension in the Setting of Basal Joint Arthritis-A Case-Control Study.

Abstract

Introduction: Surgical treatment of metacarpophalangeal (MCP) joint hyperextension in the treatment of thumb basal joint arthritis can be categorized as motion preserving and arthrodesis. We compared minimum 2-year results between nonsurgical thumbs and thumbs undergoing ligament reconstruction with tendon interposition (LRTI) alone, thumb MCP arthrodesis, and volar plate capsulodesis as adjunct procedures to LRTI.

Methods: Single surgeon patients with thumb MCP hyperextension >30° underwent arthrodesis or volar plate capsulodesis with LRTI. Thirty-one LRTI thumbs were compared with 22 LRTI with arthrodesis (LRTI + A), 21 LRTI with MCP capsulodesis (LRTI + C), and 65 nonsurgical controls. Patient-reported outcome measures were recorded with grip strength, tip pinch, lateral pinch, opposition, and pre-/postoperative hyperextension measured by one of the authors.

Results: No difference was found in Michigan Hand Questionnaire scores (P = 0.13), QuickDASH values (P = 0.38), or visual analog scale results (P = 0.86). No difference was observed in grip strength (P = 0.97) or tip pinch (P = 0.66). Lateral pinch was decreased between LRTI and nonsurgical thumbs but not when compared with groups with adjunct MCP procedures (P = 0.0064). LRTI + A had the least opposition (P < 0.001). In the LRTI + C group, MCP hyperextension worsened in two patients (9%) and 14 of 22 (63%) had postoperative values equal or greater than 30°.

Discussion and conclusion: Our LRTI + C cohort experienced persistent MCP hyperextension, with mean postoperative hyperextension of >30°. Despite the literature suggesting that this portends inferior outcomes, our LRTI + C cohort demonstrated near-equal outcomes when compared with the LRTI, LRTI + A, and control groups. We no longer perform capsulodesis for MCP hyperextension and offer arthrodesis for MCP arthrosis or hyperextension not actively correctable by the patient.