Preliminary Results of Nonconstrained Pyrolytic Carbon Arthroplasty for Metacarpophalangeal Joint Arthritis

Purpose To review early outcomes of arthritic metacarpophalangeal (MCP) joints treated with nonconstrained pyrolytic carbon implants to evaluate efficacy, clinical outcomes, and durability. Methods One hundred forty-two consecutive arthroplasties (61 patients) were retrospectively reviewed. Diagnoses included osteoarthritis (OA), traumatic arthritis, and inflammatory arthritis. One hundred thirty were primary joint replacements, and 12 were prior-silicone revisions. The average patient age was 55 years (range, 21–77 years); 36 patients were women and 25 were men. Average follow-up period was 17 months (range, 3–42 months), and 43 patients were followed up for a minimum of 1 year. Results For OA patients, according to the analog pain scale used, pain decreased from 73.0 to 8.5 of 100, functionality increased from 20.1 to 86.6 of 100, and appearance improved from 62.7 to 93.6 of 100. The rheumatoid arthritis (RA) group showed decreased pain from 43.1 to 8.9 of 100, functional improvement from 26.7 to 83.3 of 100, and increased appearance from 25.2 to 77.1 of 100. At 1 year, satisfaction was greater than 90% for both groups. Arc of motion for OA patients improved from 44° to 58°. Oppositional pinch increased 126%, and grip strength improved 40%. Rheumatoid arthritis patients increased their MCP joint motion arc from 32° to 45°. Oppositional pinch increased 89%, but grip strength decreased. Radiographs at 1 year demonstrated stable prostheses in all of the OA joints. The RA group overall demonstrated evidence of axial subsidence (10.5% of joints) and periprosthetic erosions (16.4% of joints). In RA joints with greater than 1-year follow-up period, 55.0% had axial subsidence, 95.0% had an increased radiolucent seam, and 45.0% had periprosthetic erosions. The overall implant survivorship is 141 joints to date. The overall minor complication rate was 6%, and major complication rate was 9%. Conclusions Preliminary results suggest that pyrolytic carbon MCP joint arthroplasty provides good pain relief, patient satisfaction, and functional improvement in managing OA and select cases of RA. Longer follow-up evaluation will help validate these promising early results. Type of study/level of evidence Therapeutic IV.