To assess ligament lesions and subluxations of the carpometacarpal joints of the thumbs (CMC I) of asymptomatic volunteers and of patients with CMC I osteoarthritis using advanced magnetic resonance imaging (MRI).
A total of 20 CMC I joints of 14 asymptomatic volunteers (6× both sides) and 28 CMC I joints of 22 patients (6× both sides) with symptomatic and X-ray-diagnosed osteoarthritis of CMC I joints were studied. During extension, flexion, abduction and adduction of the thumb, the anterior oblique (AOL), intermetacarpal (IML), posterior oblique (POL) and dorsal radial (DRL) ligaments were evaluated using 3-T MRI on two standard planes, and translation of metacarpal I (MC I) was assessed.
The MRI demonstrated that ligament lesions of the AOL and IML are frequent. Isolated rupture of the AOL was found in 6 of 28 (21%), combined rupture of the AOL + IML in 5 of 28 (18%) and isolated IML rupture in 4 of 28 (14%) joints. The patients had a significantly increased dorsal translation of MC I during extension with a median of 6.4 mm vs. 5.4 mm in asymptomatic volunteers (p < 0.05).
MRIs of CMC I in two standardized planes frequently show combined ligament ruptures. The dorsal subluxation of MC I, which is increased in patients, correlates with OA severity based on X-ray and can be quantified by MRI. For joint-preserving surgical procedures and for prosthesis implantation of the CMC I, we recommend performing an MRI in two planes of the thumb-extension and abduction-to evaluate the ligaments and dorsal subluxation of MC I.