Effects of Magnetic Resonance Imaging With Axial Traction of the Thumb Carpometacarpal Joint on Articular Cartilage Visibility: A Feasibility Study

Objectives The objective of this study was to verify the usefulness of magnetic resonance imaging (MRI) with axial traction of the thumb for observing articular cartilage. Materials and methods Eleven healthy adult volunteers (39.7 ± 7.4 years) without thumb carpometacarpal joint arthritis or trauma were included in this study. A 3-tesla (3T) MRI (Magnetom Skyra, Siemens Healthineers AG, Munich, Germany) of the right thumb with axial traction applied by a finger trap with three traction weights (0, 2, and 5 kg) was performed. A 3D T2* multiecho data imaging combination (MEDIC) was selected to visualize the articular cartilage. After multiplanar reconstruction, sagittal and coronal images of the thumb carpometacarpal joint were used to evaluate the articular cartilage visibility and joint space widths at five locations. Articular cartilage visibility was evaluated using our original classification method that used the percentage of the cartilage detectable area. The Friedman test was used to compare the differences between each traction weight and location. Results Articular cartilage visibility significantly improved with axial traction. The average joint space widths with the 5-kg application were 1.9 ± 0.8, 3.9 ± 0.6, 2.0 ± 0.9, 3.9 ± 1.1, and 2.5 ± 1.4 mm at the center, volar edge, dorsal edge, radial edge, and ulnar edge, respectively. The joint space widths significantly increased proportionally with the traction weight at all locations. The joint space widths at the volar and radial edges were significantly greater than those at other locations. Conclusion Applying axial traction to the thumb increased the joint space widths and improved the visibility of the articular cartilage in the carpometacarpal joint on MRI.