Magnetic resonance imaging of posterior cruciate ligament injuries: a new classification of traumatic tears.

PURPOSE

The aim of our study was to propose a new classification of acute posterior ligament (PCL) injuries based on magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Using MRI, we reviewed 220 patients presenting an acute posterior ligament injury. The MRI exam was performed on a 0.2-Tesla (T) magnet and a 1.5-T magnet using T1-weighted spin echo (SE), T2-weighted SE and fat-suppression scans [short-tau inversion recovery (STIR)] in axial, sagittal and coronal planes. In no case was paramagnetic contrast agent injected.

RESULTS

Twenty-five per cent of patients were identified as having type I lesions and another 30% as having type II lesions according to the Gross classification. Out of 77 patients, 35% of the whole sample, 37 had a tear of the posteromedial fascicle (type II lesion), and the remaining 40 had anterolateral fascicle tears (type III). In 10% of cases, the ligaments appeared completely interrupted, and these were classified as type IV lesions.

CONCLUSIONS

T1-weighted SE sequences need to be integrated with T2-weighted and STIR sequences to detect the real extent of the remaining fascicle. The MRI exam could thus be able to provide a qualitative evaluation of PCL injuries and establish how the injury compromises joint stability.