Replacement of the distal radio-ulnar joint with asemi-constrained Scheker DRUJ prosthesis.

Abstract

To describe the indications, operative technique, and long-term outcomes of patients treated with the Scheker (Aptis) distal radio-ulnar joint (DRUJ) prosthesis. The Scheker prosthesis is intended to replace the DRUJ in patients with rheumatoid, degenerative, or posttraumatic arthritis of the sigmoid notch and/or ulnar head, or in cases of gross instability of the DRUJ. Moreover, aScheker prosthesis can be used to treat failed salvage procedures, such as the Sauvé-Kapandji procedure, ulnar head resection, and ulnar head arthroplasty. Severe osteoporosis, active infection, immature skeleton, less than 14cm of the proximal ulna remaining. In supine position with the forearm in full pronation, an ulnar S‑shaped incision is made. The ulnar head is resected and the proximal part is brought to the palmar side to enable visualization of the sigmoid notch. Following preparation of the sigmoid notch and the proximal ulnar part of the radius, aradial plate is attached. When the position is verified with fluoroscopy, screw holes are drilled together with aseparate hole for the radial peg. Ametal stem is inserted in the ulnar shaft. Apolymer ball is then slid on to apolished peg on top of the ulnar stem. This polymer ball is seated in the socket of the radial plate and fixed with asmall metal cap. Radiographic images are made for confirmation of correct positioning and full pro- and supination is tested, after which the wound is closed. After 48 h of pressure bandages, patients are instructed to start with full range of motion and weight-bearing exercises under the guidance of ahand therapist. Weight-bearing is constrained to 10kg. We retrospectively assessed 50Scheker prostheses in 48patients treated between 2016 and 2021. The median age was 56years (IQR: 50-65) and 30 (60%) were female. Median follow-up was 29months (IQR: 12-48). The primary outcome was the PRWE score. The median PRWE score at the final follow-up was 23 (IQR: 4-52) for the operated side versus amedian PRWE score of 5 (IQR: 0-25) for the non-operated side (p < 0.005). Six patients had acomplication. Three patients developed extensor carpi ulnaris tendinitis with one patient requiring additional surgery. One patient developed aneuroma of the distal branch of the ulnar nerve that was surgically removed. One synovectomy was performed because of synovitis and one endoscopic ulnar release was performed because of hyperesthesia of the ulnar area. None of the prostheses had to be removed.