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

OBJECTIVE: To describe the indications, operative technique, and long-term outcomes of patients treated with the Scheker (Aptis) distal radio-ulnar joint (DRUJ) prosthesis.

INDICATIONS: 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, a Scheker prosthesis can be used to treat failed salvage procedures, such as the Sauvé-Kapandji procedure, ulnar head resection, and ulnar head arthroplasty.

CONTRAINDICATIONS: Severe osteoporosis, active infection, immature skeleton, less than 14 cm of the proximal ulna remaining.

SURGICAL TECHNIQUE: 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, a radial plate is attached. When the position is verified with fluoroscopy, screw holes are drilled together with a separate hole for the radial peg. A metal stem is inserted in the ulnar shaft. A polymer ball is then slid on to a polished peg on top of the ulnar stem. This polymer ball is seated in the socket of the radial plate and fixed with a small metal cap. Radiographic images are made for confirmation of correct positioning and full pro- and supination is tested, after which the wound is closed.

POSTOPERATIVE MANAGEMENT: After 48 h of pressure bandages, patients are instructed to start with full range of motion and weight-bearing exercises under the guidance of a hand therapist. Weight-bearing is constrained to 10 kg.

RESULTS: We retrospectively assessed 50 Scheker prostheses in 48 patients treated between 2016 and 2021. The median age was 56 years (IQR: 50-65) and 30 (60%) were female. Median follow-up was 29 months (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 a median PRWE score of 5 (IQR: 0-25) for the non-operated side (p < 0.005). Six patients had a complication. Three patients developed extensor carpi ulnaris tendinitis with one patient requiring additional surgery. One patient developed a neuroma 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.