In carpometacarpal osteoarthritis (CMC OA) of the thumb, to what extent treatments should be directed by radiographic disease severity versus pain-based indicators remains an open question. To address this gap, this study investigated the relative impact of disease severity and pain severity on the range of motion in participants with CMC OA. We hypothesized larger differences would exist between extremes in the pain severity cohort than the disease severity cohort, suggesting pain modulates movement to a greater extent than joint degradation. Thirty-one female participants (64.6 ± 10.9 years) were grouped as symptomatic or asymptomatic (pain severity cohort) and early stage OA or end-stage OA (disease severity cohort) using radiographs and questionnaires. Kinematics were measured during single-planar and multiplanar range of motion tasks. Joint angle differences between groups were statistically compared. Differences in self-reported pain, function, and disability were evident in both participant cohorts. Notably, substantial distinctions emerged exclusively during multiplanar tasks, with a greater prevalence in the disease severity cohort compared to the pain severity cohort. Participants with end-stage OA also exhibited similar overall area covered during circumduction in comparison to those with early-stage OA, despite having a decreased range of motion at the CMC joint. The study underscores the importance of assessing multiplanar tasks, potentially leading to earlier identification of CMC OA. While movement compensations such as employing the distal thumb joints over the CMC joint were observed, delving deeper into the interplay between pain and movement could yield greater insight into the underlying factors steering these compensatory mechanisms.
Keywords: joint angles; kinematics; motion capture; thumb; trapeziometacarpal.
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