Attritional Extensor Digiti Minimi Tendon Rupture Associated With a Distal Ulna Fracture

Attritional extensor tendon ruptures are common in the setting of arthritis but, to our knowledge, have never previously been reported in the setting of a distal ulna fracture. This case report describes a 56-year-old male patient who sustained a left-hand dog bite resulting in crush injuries to the thumb and ring finger and a minimally displaced distal ulna fracture. The patient initially underwent appropriate surgical intervention for the thumb and finger crush injuries and non-operative management of the distal ulna fracture with splint immobilization. He experienced an extensor digiti minimi tendon (EDM) rupture two and a half weeks post-operatively. Radiographs demonstrated interval distal ulna fracture displacement with a prominent dorsal spike and absence of arthritis. He subsequently underwent distal ulna open reduction internal fixation and an extensor indicis proprius (EIP) to EDM tendon transfer. This case demonstrates a novel complication following non-operative management of a distal ulna fracture in which the prominent dorsal distal ulna resulted in direct irritation to the extensor tendon and subsequent attritional extensor tendon rupture. This potential complication should be considered in determining appropriate treatment for distal ulna fractures.