Uncemented Total Wrist Arthroplasty Hans Christoph Meuli, MD, Diego L. Fernandez, MD, Berne, Switzerland We report our experience with a non-cemented wrist implant we developed in 1986. Between 1986 and 1991, 50 prostheses were implanted in 45 patients, 33 with rheumatoid arthritis and 12 with traumatic arthritis. After an average of 4.5 years (range, 2-6 years), we evaluated pain, daily activities, motion, grip strength, and x-ray films. The results were excellent in 24 wrists, good in 12, fair in 5, and poor in 8. (J Hand Surg 1995;20A:115-122.) During the past 25 years numerous wrist prostheses have been designed and used in pa- tients. 1-15 Our first wrist prosthesis was designed in 1970, and a report of the clinical outcome followed in 1973. ~ Because problems were encountered with its performance, the prosthesis design and the surgi- cal technique were modified in 1986.16-19 This study describes the modified implant and reports the surgi- cal technique and results in the first 50 patients. Materials and Methods Between November 1986 and January 1991, 50 prostheses were implanted in 45 patients. Thirty- five were women and ten were men. The average age was 55 years (range, 27-78). Five of the patients had bilateral procedures. Thirty-three patients had rheumatoid arthritis and 12 had traumatic osteoar- thritis. One patient died during the followup period. Thus, 44 patients with 49 prostheses were available for review in January 1993. The average followup period was 4.5 years (range, 2-6). Surgery was per- formed by five different surgeons in a multicenter study. From the Department of Orthopaedic Surgery, University of Berne, and the Department of Orthopaedic Surgery, Lindenhof Hospital, Berne, Switzerland Received for publication July 15, 1993; accepted in revised form Aug. 18, 1994. The author or one or more of the authors have received or will receive benefits for personal or professional use from a commer- cial party related directly or indirectly to the subject of this arti- cle. In addition, benefits have been or will be directed to a re- search fund, foundation, educational institution, or other non- profit organization with which one or more of the authors are associated. Reprint requests: Hans Christoph Meuli, MD, Department of Orthopaedic Surgery, Lindenhof Hospital, Bremgartenstrasse 117, CH-3012 Berne, Switzerland. Patients were examined by their surgeon after 6 weeks, 3 months, 6 months, and one year. After the first postoperative year, patients were examined yearly. Patients' satisfaction, degree of pain, and ability to perform activities of daily living were eval- uated. The examination also included measure- ments of grip strength and wrist motion and assess- ment of x-ray films. A score point system was used for rating the overall results (Table 1). Prosthesis Design The prosthesis MWP III (Meuli Wrist Prosthesis/ third revised implant) is a titanium 6-aluminum 7- niobium wrought alloy Protasul 100. The surface is corundum rough blasted. The ball head is coated with titanium nitride. The cup inset is made of UHMW-Polyethylene Chirulen. The special design of the prosthesis with two sizes in right- and left- hand versions helps to center and balance it (Fig. 1). The prosthesis is designed so that it may be either cemented or uncemented. The prongs can be con- toured to adapt to the position of the metacarpals. The unconstrained ball and socket joint allows motion in all planes as well as slight distraction (Fig. 2). Theoretical limits are 50~ of flexion, 80~ of exten- sion, 70~ of radial deviation, and 70~ of ulnar de- viation. Surgical Technique and Postoperative Treatment A 10- to 12-cm long dorsal longitudinal incision centered at the radiocarpal joint exposes the exten- sor retinaculum, which is divided at its ulnar attach- ment and elevated to the radial side. The extensor The Journal of Hand Surgery 115