[MRI of the thumb collateral ligament at the metacarpophalangeal joint: anatomy and injuries].

OBJECTIVE

To explore the anatomy and injuries features of the thumb collateral ligamentat the metacarpophalangeal (MCP) joints.

METHODS

The study was reviewed and approved by an institutional review board of hospital. Clinical imaging data of 7 healthy volunteers who without injuries and 20 patients with thumb collateral ligament injuries were retrospectively analyzed. All subjects underwent magnetic resonance examination, then comparative analysis of the normal anatomy and the thumb collateral ligament injury at MCP joints of MRI features in healthy volunteers and patients with injury. Imaging findings were compared with the surgical results and confirmed by followed up in patients.

RESULTS

Seven volunteers without ligament injures showed homogeneous low-signal-intensity on T1-weighted and proton fat saturation sequence (PD-FS) images. The average thickness of the ulnarcollateral ligament is about 2.0 to 2.3 mm, however, the normal radial collateral ligament is thinner, the average thickness is about 1.4-1.5 mm. There were 20 patients with thumb collateral ligament injuresat MCP joints, including 12 cases of ulnar collateral ligament injury and 8 cases of radial collateral ligament injury, which demonstrated poor definition, discontinuity and heterogeneously increased signal intensity in proton fat saturation sequence (PD-FS) of the involved collateral ligament. There was edema in the soft tissues surrounding the injured sites.

CONCLUSION

MRI is an accurate method for evaluation of the anatomy and pathologic conditions of the thumb collateral ligamentsat MCP joints, and it is a useful tool for early diagnosis and treatment of the thumb collateral ligaments injuries.