Magnetic resonance imaging technology in evaluating the presence and integrity of the anterior oblique ligament of the thumb

This investigation examines the reliability and reproducibility of magnetic resonance imaging (MRI) technology in evaluating the anterior oblique ligament (AOL) of the trapeziometacarpal joint (TMC) of the thumb, in order to establish an effective imaging protocol to use in the early identification of conditions leading to degenerative arthritis. We used cadaver specimens, three hand surgeons independently rated from X-rays each specimen. The specimens were then scanned in a General Electric MRI machine with a standard wrist coil. An effort was made to reproduce the image of the AOL - with a unique technique to obtain images of the obliquely oriented thumb and its ligaments. Following the MRI, the specimens were dissected to expose the AOL and visualize the TMC joint. A standard MRI fiducial was sewn to the proximal and distal extent of the volar side of the AOL. The soft tissues were replaced and the skin was closed. They were then rescanned following the same protocol, and pre and post-dissection ligament-labeled specimens were compared. Following dissection and tagging of the AOL ligament, a repeat MRI confirmed its location and validated the protocol in all cases. The open dissection and ligament tagging confirmed that what was visualized was in fact the structure of interest. This investigation demonstrated that with an appropriate MRI protocol it is feasible to guide the scanner to catch appropriate images of a ligament that is closely correlated with degenerative arthritis.