Efficacy of a Combination of Conservative Therapies vs an Education Comparator on Clinical Outcomes in Thumb Base Osteoarthritis: A Randomized Clinical Trial.

Importance A combination of conservative treatments is commonly used in clinical practice for thumb base osteoarthritis despite limited evidence for this approach. Objective To determine the efficacy of a 6-week combination of conservative treatments compared with an education comparator. Design, Setting, and Participants Randomized, parallel trial with 1:1 allocation ratio among people aged 40 years and older with symptomatic and radiographic thumb base osteoarthritis in a community setting in Australia. Interventions The intervention group (n = 102) received education on self-management and ergonomic principles, a base-of-thumb splint, hand exercises, and diclofenac sodium, 1%, gel. The comparator group (n = 102) received education on self-management and ergonomic principles alone. Intervention use was at participants' discretion from 6 to 12 weeks. Main Outcomes and Measures Hand function (Functional Index for Hand Osteoarthritis; 0-30) and pain (visual analog scale; 0-100 mm) were measured at week 6 (primary time point) and week 12. An α of .027 was used at week 6 to account for co-primary outcomes. Results Of the 204 participants randomized, 195 (96%) and 194 (95%) completed follow-ups at 6 and 12 weeks, respectively; the mean (SD) age of the population was 65.6 (8.1) years, and 155 (76.0%) were female. At week 6, hand function improved significantly more in the intervention group than the comparator (between-group difference, -1.7 units; 97.3% CI, -2.9 to -0.5; P = .002). This trend was sustained at 12 weeks (-2.4 units; 95% CI, -3.5 to -1.3; P < .001). Pain scores improved similarly at week 6 (between-group difference, -4.2 mm; 97.3% CI, -11.3 to 3.0; P = .19). At week 12, pain reduction was significantly greater in the intervention group (-8.6 mm; 95% CI, -15.2 to -2.0; P = .01). There were 34 nonserious adverse events, all in the intervention group-mostly skin reactions and exercise-related pain exacerbations. Conclusions and Relevance In this randomized clinical trial of people with thumb base osteoarthritis, combined treatments provided small to medium and potentially clinically beneficial effects on hand function but not pain. Trial Registration Australian New Zealand Clinical Trials Registry Identifier: ACTRN12616000353493.