Outcomes of pyrolytic carbon arthroplasty for the proximal interphalangeal joint.

BACKGROUND: Arthritis of the proximal interphalangeal joint is a debilitating condition commonly treated with arthroplasty. The pyrolytic carbon (pyrocarbon) implant has been developed for proximal interphalangeal joint arthroplasty in these patients. This prospective outcomes study evaluated the outcomes and complications of the pyrocarbon implant for the proximal interphalangeal joint.
METHODS: Consecutive candidates for proximal interphalangeal joint arthroplasty with pyrocarbon implants were evaluated prospectively. Functional measurements and the Michigan Hand Outcomes Questionnaire were administered preoperatively and at 3, 6, and 12 months postoperatively. Preoperative means and 12-month postoperative means for all functional measures were compared using paired t tests and nonparametric Wilcoxon signed rank sum test, and effect size was reported for the Michigan Hand Outcomes Questionnaire.
RESULTS: Fourteen patients treated with 21 implants were enrolled in the study. At the 12-month follow-up period, mean active arc of motion was 38 degrees, decreasing slightly from the preoperative value. Mean grip strength improved from 11.3 kg to 15.1 kg, although the difference was not statistically significant. Mean key pinch values improved significantly from 6.6 kg preoperatively to 9.2 kg at the 12-month follow-up (p = 0.03). Jebsen-Taylor test scores showed improvement, although not significantly. Changes in all Michigan Hand Outcomes Questionnaire domains showed a large effect size. Three patients experienced squeaking of the implant and three patients experienced dislocation of the pyrocarbon joint.
CONCLUSION: The pyrocarbon implant for proximal interphalangeal joint arthroplasty shows encouraging results, primarily in patient satisfaction and pain relief, but is associated with complications related to implant dislocations, which required prolonged treatment with external fixators.