Acute swan-neck deformity caused by thumb metacarpophalangeal volar plate injury in a child: a case report

Thumb metacarpophalangeal (MCP) volar plate injuries are rare in the pediatric population. A 14-year-old girl presented to the emergency department with an acute swan-neck deformity of the thumb. Given the clinical suspicion of an MCP volar plate injury, the patient was initially treated with an extension-blocking splint for 3 weeks, and subsequent thumb magnetic resonance imaging confirmed the diagnosis. After 3 weeks of conservative management, reassessment showed persistence of deformity. The patient therefore underwent surgical repair of the thumb MCP volar plate using an anchor, fixation of the MCP joint with a Kirschner wire, and postoperative immobilization with a cast for 4 weeks. Six months after surgical treatment, the patient demonstrated complete resolution of the deformity, a Kapandji score of 10, a Quick- DASH score of 0, and full return to sports activities. This case underscores the importance of maintaining diagnostic suspicion for MCP volar plate injuries even in atypical age groups. Once the diagnosis is established, conservative management should be considered the first-line treatment, with surgical repair reserved for cases that are refractory to nonoperative measures.