Distal avulsion of the palmar plate of the interphalangeal joint of the thumb.

A 63-year-old woman was unable to actively flex the interphalangeal joint of her right thumb after a hyperextension injury. Surgical exploration revealed an avulsion of the distal insertion of the palmar plate, allowing the bulk of the plate to block the joint during attempted active flexion. Resection of the palmar plate restored active flexion and caused no joint instability. We do not believe this lesion, which resulted in this disability, has been previously described.