Tendon versus Pyrocarbon Interpositional Arthroplasty in the Treatment of Trapeziometacarpal Osteoarthritis

BACKGROUND: Trapeziometacarpal (TMC) arthritis is treated with surgery when nonsurgical treatment fails. The best surgical option for improving pain relief, functional outcomes, and postoperative complications remains controversial. The purpose of this study was to compare clinical and radiological outcomes and complications between trapezium excision with ligament reconstruction and tendon interposition (LRTI) and pyrolytic carbon interpositional arthroplasty. METHODS: From March 2009 to August 2014, 37 patients (39 wrists) with Eaton-Littler stage II or III TMC arthritis underwent complete trapezium excision with LRTI (Group L, n=19) or pyrolytic interpositional arthroplasty (Group P, n=20). Visual analog scale (VAS) pain scores; grip and pinch strength; Kapandji scores to quantify thumb opposition; and Disabilities of Arm, Shoulder, and Hand (DASH) scores were used to compare clinical outcomes between the two groups. Radiographic changes (metacarpal shortening, subluxation, and radiolucency) were evaluated on the radiographs of thumb basal joints. RESULTS: There were no differences in patient demographics, Eaton-Littler stage, preoperative outcome measures, or the duration of follow-up between the two groups. At the last follow-up, VAS pain scores, pinch and grip strengths, Kapandji scores, and DASH scores were significantly improved in both groups compared with preoperative scores. All follow-up measurements were similar between the two groups except pinch strength, which was 1.8 kg higher in Group P (p<0.001). Proximal metacarpal migration did not differ significantly between the groups. Periprosthetic lucency more than 1 mm was observed in 7 of 20 (35%) thumbs. Complication rates were similar between the two groups. CONCLUSIONS: All subjective and objective outcomes were similar following LRTI and pyrolytic interpositional arthroplasty in patients with TMC arthritis, except pinch strength, which was more improved following pyrolytic interpositional arthroplasty. Longer follow-up is required to test adverse effects of high rates of periprosthetic lucency and prosthetic subluxation on clinical outcomes after PyroDisk interpositional arthroplasty.