gms | German Medical Science

Objectives/Interrogation: Recent research has outlined the pivotal role of psychological factors in pain and disability associated with first carpometacarpal osteoarthritis (CMC-1 OA). However, the association of pre-treatment expectations and illness perceptions (patients set of beliefs about their CMC-1) with treatment response after non-operative treatment is currently unknown. In the present study we aimed to assess the effect of psychological distress, pain catastrophizing, treatment outcome expectations and illness perceptions on the response to non-operative treatment for CMC-1 patients.

Methods: Between September 2017 and September 2018 all patients with CMC-1 OA who were non-operatively treated were included. As part of routine clinical care patients completed the Michigan Hand Questionnaire (MHQ, range 0-100) before and 3 months after treatment. A change score was calculated to measure the response to treatment. Patients also completed the Patient Health Questionnaire-4 (range 0-12), Pain Catastrophizing Scale (range 0-52), Credibility/expectancy Questionnaire (range 3-27) and the Brief Illness Perceptions Questionnaire (range 0-10) before treatment. Univariable and multivariable linear regression analysis were used to assess the effects of these factors on the change in MHQ.

Results and Conclusions: 219 patients were included in the study. Patients were predominately female (79%) and mean age was 59 years old, mean (±SD) change scores were 10.0 (±18), 5.1 (±16.4) and 5.6 (±12.8) for respectively pain, hand function and the MHQ total score. In the univariable analyses pre-treatment expectations and illness perceptions were significantly correlated with the MHQ change scores. Performing light physical labor, higher pain catastrophizing, higher expectations, and more understanding of the disease (B = 6.88[0.22 - 13.6], B = 0.38[0.05 - 0.71], B = 0.68[0.13 - 1.23] and B = 1.57[0.14 - 3.00]) were associated with more improvement in pain. Experiencing more consequences and more personal control from the illness was associated with more improvement in hand function (B = 1.33[0.02 - 2.64], B = 1.04[0.04 - 2.04]).

Discussion: Pre-treatment expectations and illness perceptions play a role in response to non-operative treatment for first carpometacarpal osteoarthritis. Our results suggest that optimizing patient expectations and illness perceptions at the start of a non-surgical treatment for thumb osteoarthritis could lead to better treatment outcomes.