Thumb metacarpophalangeal (MCP) joint subluxation is rare, with dorsal displacement being the most common type. Volar subluxations are exceptionally uncommon and frequently overlooked due to their subtle presentation and inconclusive imaging findings.
We report a rare case of type B volar subluxation of the thumb MCP joint associated with complete ulnar collateral ligament (UCL) injury, initially missed on clinical and radiological evaluation. This case highlights the importance of maintaining a high index of suspicion, careful assessment, and timely surgical intervention to restore stability and function