In briefMany sports, most commonly brief football and skiing, can result in injury to the ulnar collateral ligament of the thumb or its attachment sites. Abduction stress testing and radiographs can determine injury severity. Conservative measures can be used to treat incomplete ligament injuries and nondisplaced fractures; however, surgery is generally needed to repair complete ligament tears and displaced fractures. After adequate immobilization and physical therapy, patients can return to play if the ligament is protected with splinting or taping.