Study DesignRetrospective case series. IntroductionLiterature trends indicate that thumb dynamic stabilization may benefit clients with thumb carpometacarpal (CMC) joint pain and arthritis. There is minimal research investigating whether client characteristics predict responsiveness to hand therapy for thumb dynamic stabilization. Purpose of the Study1) To investigate how adults with thumb CMC joint pain responded to a hand therapy dynamic stabilization modeled intervention. 2) To determine if various client factors influenced responsiveness and to what extent. MethodsAn electronic medical record search identified adults treated from August 2009 through December 2015 for thumb CMC joint pain. Radiographs were retrospectively staged. Outcome measures were 1) Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) total disability score and 2) Numerical Pain Rating Scale (NPRS). Paired t-tests were performed to compare pre and post treatment measures. Multivariate analyses were used to investigate predictive factors. ResultsA total of 249 charts were analyzed. Large overall significant effects were noted for disability score (QuickDASH P <.001, X = 12.1, Cohen's d = 0.9). The average improvement of 2.1 (SD = 2.6) points exceeded the minimal clinically important difference (MCID) of 1.7 points on the NPRS pain scale. Significant predictors of QuickDASH Scores were radiographic staging, bilateral hand involvement and initial pain ratings. Significant predictors for change in pain scores (meeting or exceeding the minimal clinically important difference for the NPRS) were bilateral thumb involvement and initial “pain at worst” rating. ConclusionAfter completing hand therapy with a dynamic stabilization approach, clients had less pain and disability. Those who had unilateral thumb pain, or those who started with higher pain levels were most likely to have clinically meaningful improvements in pain. Clients in early CMC osteoarthritis (OA) stages responded better than those in later stages, indicating that early referral to therapy is important.