Ligament preserving technique for a locked metacarpophalangeal joint of the index finger.

BACKGROUND: Locking of metacarpophalangeal joint (MPJ) of the index finger occurs when volar radial osteophytes of the metacarpal head catch the accessory collateral ligament. We devised a ligament-preserving approach to quickly restore the MPJ motion while protecting the radial collateral ligament.

METHODS: We retrospectively reviewed the results of nine patients treated for a locked MPJ of the index finger. In three patients, closed reduction was successful. In six cases, volar radial osteophytes were excised from the metacarpal head using a ligament-preserving technique through a longitudinal incision on the radial side. We analyzed osteophyte shape and height as demonstrated by X-ray and computed tomography (CT). Function was evaluated by examining the range of motion, recurrence, Disabilities of the Arm, Shoulder and Hand (DASH) score, and MPJ stability based on the key pinch strength. One male and eight female patients were followed for an average of 33 months (range, 12 to 65 months); the average age of patients was 41 years (range, 34 to 47 years). The average duration of locking of the MPJ was 23 days (range, 1 to 53 days).

RESULTS: The sharp type of osteophytes was identified in six patients and the blunt type of osteophytes was indentified in three patients. The average height of radial osteophytes on the index finger metacarpal was 4.6 ± 0.4 mm in the axial CT image. At the final follow-up, the average extension limitation decreased from 26° (range, 10° to 45°) to 0°, and further flexion increased from 83° (range, 80° to 90°) to 86°. There was no recurrent locking after surgery. The DASH score improved from 24.3 to 7.2. Key pinch strength improved from 67.3% to 90.4%.

CONCLUSIONS: We obtained satisfactory outcomes in irreducible locking of the MPJ of the index finger by excising volar radial osteophytes of the metacarpal head using a ligament-preserving approach.