Thumb Osteoarthritis: A Cross-Sectional Study of Mechanisms

This study was funded by that National Institutes of Health through KL2 TR001429 and was registered as a clinical trial at the request of the funding agency. The goal of this exploratory, career development project was to conduct an observational, cross-sectional study of individuals with and without carpometacarpal osteoarthritis (CMC OA). Interestingly, even though approximately a third of postmenopausal women have radiographic evidence of CMC OA, less than ten percent of all women visit the doctor with painful symptoms. This disconnect between radiographic evidence of disease and presence of painful, clinical symptoms makes CMC OA challenging to study. Here, participants were recruited into two groups: CMC OA and age-matched controls. Participants with CMC OA were defined as those recruited from orthopaedic clinics with a diagnosis of CMC OA. Age-matched controls were defined as those recruited from the community who reported during screening that they had no pain or clinical symptoms of CMC OA. All participants participated in two sessions, a biomechanics session to evaluate movement (muscle activity, joint posture) and a somatosensory testing session to evaluate pain sensitization. All participants also completed clinical outcome measures and a hand x-ray. Analyses were completed on two groups based on radiographic evidence of CMC OA: early-stage and end-stage. Note, participant assignment to the analysis groups did not necessarily match the recruitment groups, as some control subjects had radiographic evidence of end-stage CMC OA and some individuals with diagnosed CMC OA had radiographic evidence of early-stage disease. The goal of this study was to build a small, comprehensive dataset describing how movement strategies (muscle activity and joint posture) as well as experimental and clinical pain differ across individuals with CMC OA.

Inclusion criteria

• CMC OA Subjects:

• female between the age of 40 to 90 years
• end-stage CMC OA diagnosed by a board-certified clinician
• Age-Matched Control:

• female between the age of 40 to 90 years
• no joint or muscle pain in the hand or wrist

Exclusion criteria

• All Groups:

• pregnant women; minors (under age 18); mentally disabled; any persons incarcerated, on parole, on probation, or awaiting trial
• individuals with concomitant musculoskeletal pathologies (other than osteoarthritis) in the hand or wrist, including distal radius fracture, contracture, trigger finger, and carpal tunnel
• individuals with history of uncontrolled diabetes, rheumatoid arthritis, muscular dysfunction, or neurological disease