Early results with osseointegrated proximal interphalangeal joint prostheses

Osseointegrated endoprostheses were used in 22 proximal interphalangeal joint replacements in 12 patients between 1993 and 1995. Indications for surgery were joint destruction due to rheumatoid arthritis (13 joints), primary osteoarthrosis (7 joints), posttraumatic arthrosis (1 joint), and psoriatic arthritis (1 joint). The prostheses consisted of 2 screw-shaped titanium fixtures with a flexible silicone spacer. The 1-stage surgical procedure included joint resection and cancellous bone grafting from the iliac crest before insertion of the titanium fixtures. At a follow-up examination 27 months (range, 12-37 months) after surgery, the average active range of motion was 56 degrees (20 degrees to 80 degrees) with an extension lag of 11 degrees (-5 degrees to 45 degrees), corresponding to an average arc of motion of from 11 degrees to 67 degrees flexion. Radiographs indicated that 41 of 44 fixtures were osseointegrated. Four of the 22 joint mechanisms showed fracture of the silicone spacer; deformation of the silicone was noted in an additional 27%. Patient satisfaction was high (20 of 22 joints), with significantly improved range of motion and hand function, increased grip strength, good pain relief, and satisfactory appearance. The results of this study indicate good early clinical findings using osseointegrated implants for proximal interphalangeal joint replacement but also show the need for further development regarding the durability of the flexible silicone joint spacer.