The spectrum of ulnar collateral ligament injuries as viewed on magnetic resonance imaging of the metacarpophalangeal joint of the thumb.

OBJECTIVE

To elucidate the spectrum of ulnar collateral ligament (UCL) injuries detectable by magnetic resonance imaging (MRI).

METHODS

Twenty-one patients (12 male and 9 female, aged 14-62 years) with acute hyperabduction injuries of the first metacarpophalangeal joint underwent MRI for clinically suspected UCL injuries. All scans were performed in either a large-bore, 1.5-T imager or an experimental small-bore, 1.9-T imager. MRI findings and clinical evaluations of all patients and surgical reports of those who underwent surgery (n = 10) were reviewed and correlated retrospectively.

RESULTS

A total of 6 patients demonstrated injuries that did not fall into previously described categories of UCL injuries and therefore illustrated the existence of a subclass of UCL injuries. We divided the MRI findings into 5 categories: Stener's lesions (n = 6), moderately displaced (> or = 3 mm) complete tears (n = 5), minimally displaced (< 3 mm) complete tears (n = 4), nondisplaced complete tears (n = 3) and partial tears (n = 3). None of the MRI scans demonstrated a normal UCL. Although sensitivity and specificity were not calculated, only 2 cases demonstrated discordance between the MRI results and surgical findings or clinical outcomes.

CONCLUSION

There is a spectrum of UCL injuries that have not previously been described.