Imaging the ligaments of the trapeziometacarpal joint: MRI compared with MR arthrography in cadaveric specimens.

OBJECTIVE The purpose of our study was to compare the normal ligamentous anatomy of the trapeziometacarpal joint in cadavers on conventional MRI and MR arthrography and review the most common diseases and abnormalities that affect this articulation. MATERIALS AND METHODS MR images of seven trapeziometacarpal joints of seven fresh cadaveric hands were obtained before and after arthrography. The MR appearances of the ligaments around the trapeziometacarpal joint were analyzed and correlated with corresponding anatomic sections. The imaging planes that allowed best analysis of these structures were determined. RESULTS Five ligaments around the trapeziometacarpal joint were generally recognized: the dorsoradial ligament; the posterior oblique ligament; the intermetacarpal ligament; the ulnar collateral ligament (UCL); and both portions of the anterior oblique ligament, the superficial anterior oblique and deep anterior oblique ligaments. The former three were attached to the dorsal aspect and the latter three to the volar aspect of the trapeziometacarpal joint. The dorsoradial ligament, posterior oblique ligament, intermetacarpal ligament, and superficial and deep anterior oblique ligaments were best visualized in the sagittal plane, whereas the UCL was best visualized in the coronal plane. MR arthrography mainly improved visualization of the intermetacarpal ligament, superficial and deep anterior oblique ligaments, and UCL. CONCLUSION MR arthrography improves visualization of and provides detailed information about the anatomy of the ligaments around the trapeziometacarpal joint. Knowledge of the appearance of these normal ligaments on MRI allows accurate diagnosis of lesions of the trapeziometacarpal ligaments and of the adjacent structures and aid the attending physician if and when surgery is indicated.