The authors retrospectively analyzed 31 patients who received a Scheker total distal radioulnar joint prosthesis (APTIS Medical, Louisville, KY, USA) for treatment of a failed partial or complete distal ulna resection, a failed distal radioulnar joint fusion, or painful distal radioulnar joint degenerative arthritis. The mean patient age at the time of surgery was 46 years (range, 18-70 years), and the average follow-up interval was 6.0 years (range, 4-9 years). Pain on a 5-point visual analog scale decreased preoperatively from a mean of 4.2 to 1.0 at follow-up. Forearm rotation, grip strength, and weight bearing increased in nearly all cases. Complications included 1 peri-prosthetic infection (salvaged with a 2-stage re-implantation), and 2 cases of ulnar implant failure attributed to trauma.
Unlike other ulnar endoprostheses that replace only the ulnar head, the Scheker prosthesis replaces the ulnar head, resurfaces the lesser sigmoid notch, and is semi-constrained in design. The first generation implant described in this report is cementless and constructed from stainless steel and ultra high molecular weight polyethylene. The second generation Scheker device is made from a stronger metal alloy (cobalt chromium) and treated with a plasma titanium spray to permit bone ingrowth. Further outcome study is necessary owing to the inherent potential for implant failure with a bipolar, semi-constrained arthroplasty device.