S45 SHORT AND MIDTERM RESULTS AFTER MP JOINT ARTHROPLASTY WITH THE CEMENTLESS, UNCONSTRAINED ELOGENICS PROSTHESIS IN PATIENTS WITH RHEUMATOID ARTHRITIS

Abstract

Background: In 80% of patients with rheumatoid arthritis the metacarpophalangeal (MP) joints are involved with increasing destruction and loss of function. Silicone arhtroplasties of the MP joints produce a limited range of motion, increasing osteolysis and fractures of the implants. The cementless, unconstrained design of the ElogenicsTM prosthesis is a new concept for treating the MP joints of rheumatoid patients.

Methods: In a prospective study 72 ElogenicsTM prosthesis were implanted, 62 in patients with rheumatoid arthritis, osteoarthritis (n=4), polyarthritis (n=5) and 1 after revision of a silicone implant. The patients were reexamined after an average follow up of 21 months (12–51 months) clinically and radiologically.

Results: The average active range of motion for extension to flexion increased from 0/18/65° before surgery to 0/14/71° after surgery. The remaining ulnar drift was 12° (preoperative 18°!). Pain in the visual analogue scale improved from 2.3 to 1.7 postoperatively. Eight palmar luxations of the implants were recognized. They were revised and are stable during the follow-up. No infection occurred. Two prostheses were changed because of loosening. The X-rays showed osteointegration in the metacarpal components. Radiolucent zones were found in progress at the basis on the palangeal components.

Conclusion: The short- and midterm results after implantation of the cementless, unconstrained ElogenicsTM prosthesis show an improved hand function and pain relief. The design of the implant may solve the accepted postoperative problem of instability of the MP joints.