Abstract
<title>Abstract</title> <p>Background. Base-of-thumb osteoarthritis affects the trapeziometacarpal joint and causes pain and limitations affecting hand activities of daily living. Identifying factors associated with hand disability may help guide therapeutic strategies. In the present study, we aimed to assess factors associated with hand-specific activity limitations in base-of-thumb osteoarthritis. Methods We conducted a secondary cross-sectional analysis of baseline data from two randomized controlled trials, RHIBOT (N = 60) and RHIZORTHÈSE (N = 112). Participants were classified according to the severity of hand-specific activity limitations using the Cochin Hand Function Scale, with unacceptable limitations defined as a score > 26/90. Baseline demographic, clinical, and functional variables were described and compared. Multivariable logistic regression analysis was used to identify factors independently associated with unacceptable hand-specific activity limitations. Results Among the 172 participants included (mean age 63.8 years; 86% women), 59 (34.3%) had unacceptable hand-specific activity limitations. Participants with unacceptable limitations reported higher pain intensity and lower thumb opposition. In multivariable analysis, higher pain intensity (odds ratio [OR] 0.95, 95% CI 0.93–0.97; p < 0.001) and reduced thumb opposition (OR 1.58, 95% CI 1.03–2.41; p = 0.035) were independently associated with hand-specific activity limitations. Conclusion In individuals with base-of-thumb osteoarthritis, pain intensity and thumb mobility are the main factors associated with hand-specific activity limitations. These results highlight the importance of interventions targeting pain control and preservation of thumb mobility.</p>