[First experience with total wrist replacement using an implant of our design].

PURPOSE OF THE STUDY

To present the results of total wrist replacement with a cementless prosthesis designed by us.

MATERIAL AND METHODS

A group of five men and 27 women treated between 2004 and 2007 was evaluated. The average age was 51.6 years and follow-up ranged from 4 to 38 months, with an average of 9.4 months. Indications for surgery included wrist destruction due to rheumatoid arthritis, arthritis or psoriatic arthropathy. Subjective evaluation recorded satisfaction of the patients with the wrist range of motion, cosmetic appearance of the hand and pain relief. The range of motion was assessed with a goniometer at 4 months of follow-up on average. Radiographs were made immediately after surgery and then at 6 and 12 months post-operatively.

RESULTS

All patients reported pain relief, 23 were satisfied with wrist mobility and hand appearance, and seven were only partly satisfied and would have preferred a greater range of motion. Two patients were dissatisfied with an ulnar deviation of the carpal axis and therefore revision arthroplasty of the radial ligamentary and tendinous structures was planned. No aseptic or septic loosening of the implant or its migration was found.

DISCUSSION

The current total wrist arthroplasty has evolved from Swanson silastic implants to prostheses with a metal-on-polyethylene bearing whose active surfaces are firmly fixed in bone. In today's Europe, the most frequently used prostheses are Meuli implants or the latest modification of the Guepar implant, which is very close to the Universal 2 implant. In the USA since 1985, Professor's Beckenbaugh's BIAX implant has continuously been improved. The implant designed by us is based on all well-tired implant components and aims at being as similar to the anatomical wrist structures as possible. The socket is fixed in the distal radius. The carpal components involve the main fixation shaft for the third metacarpal and a short antirotation pin for the second metacarpal base. A metal head is assembled onto a tapered shaft extending from the carpal component transversal zone. The implant is made of titanium alloy, in some parts coated with hydroxyapatite; the sockets has a polyethylene liner.

CONCLUSION

Total wrist replacement is usually preceded, particularly in surgery for rheumatoid arthritis, by operations intended to prevent or slow down gradual wrist destruction. The usual salvage procedures include surgery on soft tissues (synovectomy, tenodesis, tendon reconstruction) and/or bone (limited wrist arthrodesis, Sauve-Kapandji procedure). These procedures usually have a temporary effect and total replacement will be the next step in surgical treatment. For the most severe destruction associated with subluxation and wrist instability, total arthrodesis in a neutral wrist position still remains the method of choice. The first results with use of the implant of our design show that this total wrist replacement allows us to preserve or restore the wrist range of motion and to improved grip strength.