Eight-Year Neglected Pediatric Kaplan's MCP Dislocation Following Childhood Trauma Managed by Volar Open Reduction: A Case Report.

Introduction: Kaplan's dislocation is a rare complex metacarpophalangeal (MCP) joint dislocation in which soft-tissue interposition prevents closed reduction. Chronic neglected cases in children are extremely uncommon and present significant diagnostic and therapeutic challenges. Case Report: We report the case of an 11-year-old left-hand-dominant boy who presented with deformity and restricted motion of the left index finger 8 years after childhood trauma. Radiographs demonstrated a chronic dorsal dislocation of the second MCP joint consistent with Kaplan's lesion. An initial attempt at closed reduction with distraction failed to maintain reduction. Open reduction through a volar approach revealed dense fibrosis of the volar plate and capsule acting as the mechanical block to reduction. After release and repair of these structures, stable reduction was achieved and maintained using transarticular K-wire fixation. At 6-month follow-up, the patient regained full range of motion with good pincer grip and no residual instability. Conclusion: Neglected pediatric Kaplan's MCP dislocations are rare but can be successfully treated with volar open reduction, which allows direct visualization and release of obstructing volar structures, leading to excellent functional outcomes.