Dislocation of the First Metacarpophalangeal Joint Complicated by the Interposition of the Thumb Sesamoid Bones: A Case Report

We present a case of a thumb metacarpophalangeal (MCP) joint dislocation complicated by the interposition of the sesamoid bones. This case highlights a clinical scenario referred to as the "locked thumb" syndrome, in which a first-digit MCP dislocation is complicated by an entrapped anatomical structure that hinders closed reduction. In this case, the thumb sesamoid bones became lodged at the base of the dislocated proximal phalanx. Due to this mechanical blockage, bedside closed reduction failed, and operative management was required.