Ulnocarpal abutment is a condition where a prominent end of the ulnar bone of the forearm causes degeneration of the joint surfaces in the wrist. Shortening the ulnar very slightly can correct this prominence and resolve the pain of the condition. Ulnar shortening can also be an effective treatment of other wrist pathologies such as TFCC tears.
The main indication is ulnar sided wrist pain with evidence of degeneration of the lunate bone in the wrist (ulnocarpal abutment).
Ulnar shortening is performed under general anaesthetic as day surgery. Anticoagulant medication would normally be stopped prior to surgery in consultation with your doctor. The hospital will confirm admission and fasting times.
An incision is made in the mid forearm over the ulna. Using a cutting guide, a 2-4mm wide segment of the ulnar is removed and the gap closed. The ulna is then fixed with a specialized plate and x-rays are taken.
The wrist is immobilized in a plaster for the first 2 weeks, and then gentle range of motion exercises are started with the hand therapists. Weight bearing on the arm is avoided for the first 8 weeks or until union of the osteotomy is seen on x-rays.
Although rare, ulnar shortening osteotomies occasionally do not unite, requiring a further procedure with bone grafting to achieve union.
The main alternative for most indications for ulnar shortening would be ongoing physiotherapy and activity modification.