Effectiveness of exercise therapy in patients with thumb carpometacarpal osteoarthritis: A multicenter, randomized controlled trial

Objective: To compare the effectiveness and costs of an orthosis + exercise therapy with only an orthosis on pain at 3 months and conversion to surgery <1 year in patients with thumb carpometacarpal (CMC-1) osteoarthritis (OA). Design: Multicenter, single-blinded, randomized controlled trial. Setting: Eighteen outpatient hand surgery and therapy clinics in the Netherlands. Participants: Adult patients with CMC-1 OA. Interventions: Orthosis + exercise therapy versus orthosis-only. Primary outcome measures: Pain at 3 months (Michigan Hand Outcomes Questionnaire pain subscale) and conversion to surgery <1 year. Results: We included 166 patients (81 orthosis + exercise, 85 orthosis-only). There was no difference between the orthosis + exercise group and the orthosis-only group in pain at three months (least mean square difference 3.7 [95% CI −1.0–8.3]). Conversion to surgery was 4.9% (n=4) in the orthosis + exercise group and 9.4% (n=8) in the orthosis-only group, which was not significantly different (risk difference 4.7% [-3.3–12.2%) due to the low conversion to surgery rates. The total societal costs for orthosis + exercise were 37% (-€825 [-2072–421]) lower per patient than orthosis-only. The orthosis + exercise group had favorable outcomes in MHQ subscale activities of daily living scores (6mo), work ability (all time points), satisfaction with hand (3mo), the MHQ total score (3mo, 6mo), satisfaction with treatment results (all except 6mo), grip strength (6w), and illness perceptions (3mo). Conclusions: In patients with CMC-1 OA, an orthosis + exercise therapy is preferred over orthosis-only because of the favorable secondary outcomes. Trial registration: ClinicalTrials.gov: NCT05772715.