Metacarpophalangeal Chondrodesis With a Stiletto Flap for the Congenital Clasped Thumb in Children With Arthrogryposis.

Congenital clasped thumb is characterized by a fixed flexion and adduction deformity of the thumb at the metacarpophalangeal (MCP) joint. In complex and syndromic cases, particularly those associated with distal arthrogryposis, the deformity may involve multiple structures, including first webspace contracture with deficient volar skin, shortening of the flexor pollicis longus, tightness of the adductor pollicis and first dorsal interosseous muscles, and MCP joint instability with abnormal articular surfaces. Supple thumbs typically respond to serial splinting and stretching, whereas rigid deformities that are refractory to nonoperative treatment require surgical correction with soft-tissue release, webspace deepening, volar thumb resurfacing, and MCP joint stabilization. We describe a technique that pairs a radially-based index finger stiletto flap with a growth-preserving MCP chondrodesis. The stiletto flap both opens the first web and resurfaces the volar thumb with durable glabrous-adjacent skin. The chondrodesis stabilizes the MCP joint in extension while preserving the proximal phalangeal physis and its secondary ossification center, which maintains longitudinal growth of the thumb. Fractional lengthening of the flexor pollicis longus and release of the adductor pollicis and first dorsal interossei address the remaining extrinsic and intrinsic contractures. The technique repositions and stabilizes the thumb in a growing hand while preserving longitudinal physeal growth. Surgeon-specific outcomes are the subject of ongoing follow-up.