[Resurfacing prosthesis for osteoarthritis of the trapeziometacarpal joint: 4.5 year follow-up in 83 implants].

PURPOSE OF THE STUDY

The aim of this study was to present our experience with hemiarthroplasty of the base of the first metacarpal for the treatment of degenerative disease of the trapeziometacarpal joint. We have used this resurfacing implant since 1995 as part of our therapeutic armamentarium together with trapeziectomy, arthrodesis and total arthroplasty.

MATERIAL AND METHODS

The chromium-cobalt implant is inserted into the base of the first metacarpal. Three implant sizes are available. The present series included 106 implants in 87 patients, predominantly female. Mean patient age was 59.6 years. Three quarters of the patients had isolated joint degeneration. The preoperative complaint was pain (scored 3 on a 4-point scale) for 92% of patients. Joint motion was generally not impaired. Grip force was limited with less than 50% force for first finger-thumb opposition in three quarters of the patients. The anterior Gedda-Möberg approach was used in all cases. The joint was immobilized for two to three weeks postoperatively.

RESULTS

There were seven complications among the 106 cases: reflex dystrophy (n=4), global pain (n=2) and rupture of the long extensors (n=1). Sixty nine patients (83 implants) were reviewed at more than one year follow-up. Mean follow-up was 53 months (range 23 - 128 months). Activities were resumed at two months for 88% of implants with no problem for grip force for one-third and normal activity for 66%. Patient assessment was: outcome good and very good for 94%, pain free for 52%, and moderate pain without impaired activity for 43% (Kapandji opposition score was normal in 90%). Grip force was decreased in 25%. Radiographically, all implants were stable. Joint centering was improved (from 25% to 60% at last follow-up). There was no correlation between radiographic centering and clinical outcome.

DISCUSSION

This hemiarthroplasty has provided satisfactory results in terms of pain relief, joint motion, and function. There has not been any long-term radiographic problem. If revision is needed for failure, the procedure is simple and trapeziectomy, total arthroplasty or arthrodesis can be performed. The hemi-implant can be inserted after total arthroplasty. Compared with other techniques, this implant avoids the problem of silicone tolerance with the Swanson implant and has provided results superior to those of arthrodesis and trapiezectomy but slightly less satisfactory than with total arthroplasty. The indication for use of this resurfacing implant is osteoarthritis of a centered trapeziometacarpal in the young subject. The implant is contraindicated for advanced-stage disease, stiff joint with retraction of the first commissure and hyperextension of the metacarpophalangeal joint.