Rupture of all the flexor tendons in the hand due to malunion of a distal radius fracture.

We report the case of a patient in whom the flexor digitorum superficialis and flexor digitorum profundus tendons to the index, middle, ring and little fingers ruptured 6 years following malunion of a distal radius fracture. There was no history of rheumatoid disease. The distal ulna was displaced volarly and perforated the volar wrist capsule. There was a cumulative biological effect from chronic synovitis and mechanical compression due to the ulnar head impinging upon the normal anatomic course of the flexor tendons to the ring and little fingers. We discuss the physiopathology of this rare lesion and postulate that flexor tendon rupture to the index and middle fingers will occur on the volar surface of the radius when there is a malunion with dorsal tilt.