Male with a Thumb Out of Joint

We report the case of a 53-year-old man who presented to the emergency department with persistent thumb pain and instability after trauma and was found to have radial collateral ligament injury of the thumb metacarpophalangeal joint. Although emergency physicians are commonly taught to recognize ulnar collateral ligament injuries, radial collateral ligament injuries are less common, may be overlooked, and can lead to chronic instability, weakness, and degenerative change if not identified. It is important for emergency physicians to be aware of this injury because delayed diagnosis may result in substantial functional morbidity.