Save the trapezium: double interposition arthroplasty for the treatment of stage IV disease of the basal joint.

Twenty patients with symptomatic stage IV basal joint (pantrapezial) arthritis were treated with double interposition arthroplasty, a new technique that resurfaces the degenerative trapeziometacarpal and scaphotrapezial joints after minimal distal trapezial resection. The results of the 21 procedures were reviewed clinically and radiographically after a mean follow-up period of 34 months (minimum, 1 year). Ninety-one percent of the patients were completely satisfied. Seventy-one percent were entirely free of pain, and an additional 24% noted only occasional, mild, high-stress pain that did not limit their activities. One case was a clinical failure. Objectively, all 21 basal joints were stable, with active range of motion to within 90% of normal. Mean grip strength increased 32%, from a force of 26.1 kg to 33.9 kg (p < .01). Key pinch strength increased from a force of 5.3 kg to 6.0 kg (an 11% increase; p = .05). A new method of determining changes in basal joint height indicated a mean decrease in height of 5.3% (range, 0%-12%) at rest and 8.1% (range, 0%-20%) under axial compression. This difference was statistically but not functionally significant. Overall, there were 95% good or excellent results and 1 poor result. We believe this technique is simple and preserves the osseous foundation of the basal joints. These results compare favorably with arthroplasties that include trapezium excision for the treatment of stage IV basal joint arthritis.