Thumb Basal Joint Arthritis - Can we Get New Insights Using MRI?

Background: Primary osteoarthritis of the thumb carpometacarpal joint is a common medical problem which causes pain and functional disability. It is manifested by inflammatory changes in the soft tissues, cartilage and bone which cause destruction of the joint architecture and secondary changes to adjacent joints.

Although clinical and radiographic criteria using common x-ray, are typically used for treatment decisions, they do not provide information regarding cartilage and soft tissue changes. Newer imaging methods can demonstrate cartilage injury, bone marrow edema, synovitis, ligament injury and other features that may contribute to our understanding of the disease and guide treatment in a more accurate way.

Our objective in this study is to assess soft tissue, cartilage and periarticular changes in symptomatic patients using Magnetic Resonance Imaging.

Methods: During 2018 we enrolled 30 patients who were referred to our clinic for treatment with symptomatic, X-ray diagnosed CMC1 arthritis. We performed an MRI on a standard plane and checked the images for periarticular ligaments (anterior oblique, posterior and intermetacarpal), joint space narrowing, marrow edema, intraarticular fluid and joint alignment. The studies were independently evaluated by 2 separate orthopedic surgeons. We then compared the findings to radiologic changes using the Eaton – Littler classification system and to clinical features using the DASH score.

Results: Soft tissue lesions were common in all patients included in the study. Severity of the changes correlated with the stage of arthritis according to the Eaton – Littler classification. There was also a correlation between the number of injured ligaments and the severity of the disease.

Conclusions: MRI can be used as a diagnostic tool for CMC1 arthritis to expand our understanding of the disease severity and guide treatment based on subtle changes that may not be demonstrated on the currently used diagnostic methods.