High dose soft orthosis for thumb carpometacarpal osteoarthritis in addition to best practice usual care: A feasibility randomised controlled trial

Introduction: Carpometacarpal osteoarthritis (CMC OA) is a common problem in mid-older aged adults. Existing guidelines are ambiguous with respect to materials, design and duration of use of orthoses to manage hand OA. A limitation of studies to date is the low dose (hours per day) of orthosis wearing. This study aimed to evaluate the feasibility of investigating the effectiveness of a soft prefabricated orthosis worn at high dose in conjunction with best practice usual care for CMC OA. Methods: Study design: Pragmatic, 2-arm parallel-group feasibility RCT. Adults aged ≥40 years with symptomatic CMC OA were randomised to either best practice usual care or usual care in conjunction with a soft neoprene orthosis prescribed to wear 20 h per day, for 4 weeks. A priori feasibility criteria were: (1) enrolment of 30 participants in 4 months; (2) retention >85% at 6 months; (3) intervention adherence on >80% days; (4) interventions acceptable >90% of participants. Outcome measures were collected at baseline, 4 weeks, and 6 months; analysis used descriptive statistics. Results: Thirty participants were enrolled within 4 months; 97% retained at 6 months. Orthosis wearing achieved ≥20 h on 68% of days. Exercise adherence was 80% on ≥89% of days in both groups. Interventions were acceptable. Clinically significant improvements in pain occurred in both groups. Discussion: High dose orthosis wearing may be acceptable and feasible for managing CMC OA. Orthosis amendments and a wear target of 18 h are recommended for future investigation of this intervention.