Predicting Outcome After Hand Orthosis and Hand Therapy for Thumb Carpometacarpal Osteoarthritis: A Prospective Study.

Objectives: (1) To identify predictive factors for outcome after splinting and hand therapy for carpometacarpal (CMC) osteoarthritis (OA) and to identify predictive factors for conversion to surgical treatment; and (2) to determine how many patients who have not improved in outcome within 6 weeks after start of treatment will eventually improve after 3 months.

Design: Observational prospective multicenter cohort study.

Setting: Xpert Clinic in the Netherlands. This clinic comprises 15 locations in the Netherlands, with 16 European Board certified (FESSH) hand surgeons and over 50 hand therapists.

Participants: Between 2011 and 2014, patients with CMC OA (N=809) received splinting and weekly hand therapy for 3 months.

Intervention: Not applicable.

Main Outcome Measures: Satisfaction and pain were measured with a visual analog scale and function with the Michigan Hand Questionnaire at baseline, 6 weeks, and 3 months posttreatment. Using regression analysis, patient demographics and pretreatment baseline scores were considered as predictors for the outcome of conservative treatment after 3 months and for conversion to surgery.

Results: Multivariable regression model explained 34%-42% of the variance in outcome (P<.001) with baseline satisfaction, pain, and function as significant predictors. Cox regression analysis showed that baseline pain and function were significant predictors for receiving surgery. Of patients with no clinically relevant improvement in pain and function after 6 weeks, 73%-83% also had no clinically relevant improvement after 3 months.

Conclusion: This study showed that patients with either high pain or low function may benefit most from conservative treatment. We therefore recommend to always start with conservative treatment, regardless of symptom severity of functional loss at start of treatment. Furthermore, it seems valuable to discuss the possibility of surgery with patients after 6 weeks of therapy, when levels of improvement are still mainly unsatisfactory.