Joint Distraction for Thumb Carpometacarpal Osteoarthritis: 2-Year Follow-up Results of 20 Patients.

Joint distraction is a fairly new treatment for patients with symptomatic thumb carpometacarpal osteoarthritis (CMC1 OA). A previous pilot study of five patients showed that CMC1 joint distraction is technically feasible. The current study presents the results of CMC1 joint distraction in 20 patients with a 2-year follow-up period.  The primary study aim was to assess if patients with CMC1 OA have better physical function and less pain 2 years after CMC1 joint distraction. Second, we assessed the number of patients who achieved a minimal clinically important difference (MCID) in patient-reported outcome measures at each follow-up time point. Furthermore, this study sought differences on magnetic resonance imaging (MRI) of the CMC1 joint before and after distraction. Adverse events were noted and reported.  Twenty patients (median age of 54 years) with symptomatic CMC1 OA and an established indication for a trapeziectomy were enrolled. An external distractor device was placed over the CMC1 joint and left in situ for 8 weeks. Disabilities of the Arm, Shoulder, and Hand (DASH) score, Michigan Hand Outcome Questionnaire (MHQ), visual analogue scale (VAS), and grip strength were recorded preoperatively and at 3, 6, 12, and 24 months postoperatively.  Two years after joint distraction, physical function and pain scores had improved significantly compared with baseline: DASH from 48 to 17, MHQ from 56 to 83, and VAS for pain from 50 to 18 mm. Fourteen of 19 patients (74%) reached an MCID in DASH and MHQ scores. One patient was not satisfied with treatment outcome and chose to proceed with a trapeziectomy 14 months after initial distraction therapy.  This study demonstrates that CMC1 joint distraction can postpone more invasive surgical interventions (e.g., trapeziectomy) for at least 2 years. Larger comparative studies are needed to assess the value of CMC1 joint distraction in the treatment of CMC1 OA.  This is a Level IV, prospective case series study.