Hand Case 10 Background

Injury to the ulnar collateral ligament (UCL) of the thumb can cause significant long term morbidity if not properly diagnosed. The UCL helps stabilize the thumb MCP joint. It inserts on the ulnar side of the proximal phalanx (next to the webspace). UCL disruption causes significant instability. There is often an associated avulsion fracture (20%) of the time) at the insertion of the UCL (as in this case).