2024 Volume 19 Issue 2 Pages 23-00296
Analyzing the biomechanics of the thumb carpometacarpal (CMC) joint is essential for elucidating the etiology of osteoarthritis (OA) and for developing a mechanics-based treatment. This study aimed to identify the areas where the peak stress in the cortical bone is likely to occur during thumb motion. We also investigated whether the stress in the first metacarpal and trapezium differ. CT scan was performed on 11 healthy adult men during flexion and abduction. 3D CMC joint models were created from CT images and then finite element (FE) models under the static compressive force in the bone axial direction of the first metacarpal were constructed. As a result, the peak stress in the cortical bone of the first metacarpal tended to be concentrated in the volar–central region, and that of the trapezium was uniformly distributed across the entire articular surface. Furthermore, the trapezium had higher stress in the cortical bone than the first metacarpal. These results suggest that the volar–central region of the first metacarpal is easily worn, and that the trapezium is evenly worn. These results also suggest that wear is likely to progress from the trapezium.
