S46 WFR (WRIST FUSION ROD) FOR RHEUMATOID WRIST ARTHRODESIS

Abstract

Background: Total wrist arthrodesis is a reliable procedure for severely deteriorated and unstable rheumatoid wrist. In 1999, we developed a new wrist fusion rod (WFR), a cannulated titanium rod could be buried into the third metacarpal with proximal fins and a transverse pin to prevent the rod migration and rotation in the medullary canal. After bone preparation, the 4 mm diameter rod was inserted through a guide pin in ante-grade fashion from the carpus to the neck of the third metacarpal to prevent metacarpal fracture. Then the rod was inserted in retrograde fashion into the radius with an introducer, and countersunk until the distal end of the reached the metacarpal isthmus. After burying the rod, it was bent to the desired angle using a special bender.

Materials and Methods: Total wrist arthrodesis was performed using this rod on 39 wrists in 33 patients with rheumatoid arthritis (6 males and 27 females). Their radiographic change was Larsen grade IV or V with subluxation at the radiocarpal joint. The mean age at the operation was 60 yrs. old (28 to 75), and the mean duration of the disease was 12 yrs. (3 to 40). The mean follow-up period was 39 mos. (5 to 75). Supplemental fixation with staples was incorporated in this intramedullary fixation. Iliac bone was grafted on 8 mutilated wrists in 8 patients. Postoperative immobilization using a short arm cast or a wrist brace was continued for 8 weeks.

Results: Preoperative pain and swelling disappeared in all operated wrists, and grip strength increased in 31 wrists (79%). The mean preoperative grip strength increased from 97 mmHg to 124 mmHg postoperatively. Subluxated wrist was reduced and fused in slight extension and slight ulnar deviation. The rod did not migrate distally or proximally in the medullary canal. Bony fusion was obtained in 36 wrists (92%). Four rods (10%) were broken due to an overuse or a fall before completion of fusion; however, they did not cause any pain. There were no major complications.

Conclusion: Using this WFR, rigid fixation at the desired angle was obtained in the total wrist arthrodesis on rheumatoid wrist. It is technically simple, safe and fast to use.