Swan-Neck Deformity as a Rare Complication of a Fifth Metacarpal Fracture: Surgical Correction Using the Aiache Technique.

Metacarpal fractures are among the most common hand injuries, with the fifth metacarpal being the most frequently involved. While many cases can be managed nonoperatively, surgical intervention is required when instability, malrotation, or marked angulation is present. We present an unusual complication of swan-neck deformity following fixation of a fifth metacarpal shaft fracture with a dorsal titanium miniplate in a 16-year-old male patient. Initial fixation provided stability; however, progressive deformity developed, characterized by hyperextension of the proximal interphalangeal joint, with compensatory flexion of the distal interphalangeal joint - likely related to extensor tendon imbalance from scarring or hardware placement. Due to the functional and cosmetic implications, corrective surgery using the Aiache technique was performed. Postoperative follow-up demonstrated bone consolidation, improved range of motion, pain relief, and restoration of hand function. This case highlights the importance of recognizing rare postoperative complications after dorsal plating of metacarpal fractures. Although swan-neck deformity is uncommon, it can result in significant disability if untreated. The Aiache technique offers a reliable reconstructive solution by directly correcting extensor mechanism imbalance and restoring digital alignment, underscoring the need for careful postoperative monitoring to preserve optimal hand biomechanics.