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

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.