Airbag-Associated Bilateral Thumb Metacarpophalangeal Joint Ulnar Collateral Ligament Injury

We report a case of simultaneous bilateral thumb metacarpophalangeal ulnar collateral ligament avulsions resulting from airbag deployment during a motor vehicle crash. Upper-extremity airbag injuries are common, but it is rare to sustain bilateral thumb metacarpophalangeal joint ulnar collateral ligament avulsions. In addition, the location of the avulsions was unusual because they occurred proximally rather than the more common distal ulnar collateral ligament injuries. It is possible that injury caused by airbag deployment favors symmetrical proximal injury of the ulnar collateral ligament. Key words: airbag, thumb metacarpophalangeal joint ulnar collateral ligament