[Antero-posterior lesions of the superior glenoid labrum. Magnetic resonance evaluation].

PURPOSE

To assess MR potentials in the evaluation of superior glenoid labrum disease and possible associated conditions of the rotator cuff and of the anterior mechanism of the shoulder.

MATERIAL AND METHODS

We retrospectively evaluated 51 patients (age range 18 to 53 years) with a diagnosis of anteroposterior lesion of the superior glenoid labrum. MR examinations were performed with a 0.2 T permanent magnet and a dedicated coil, using T1- and T2-weighted SE sequences on mostly coronal-oblique planes. Slice thickness was 4 mm. In 8 cases, the examination was completed with intra-articular injection of contrast agent. Twenty-eight patients were submitted to surgery (arthrotomy in 7 cases; arthroscopy in 21 cases).

RESULTS

We considered only the cases with surgical confirmation and divided them into 2 groups: 15 patients with isolated alteration of the superior glenoid labrum and 13 patients with an anteroposterior lesion of the glenoid labrum associated with disease of the rotator cuff or of the anterior mechanism of the shoulder. MRI demonstrated 5 cases of superior labrum irregularities at the level of its glenoid insertional portion (type I lesion); 6 cases of detachment of the superior portion of the labrum (type II); 9 cases of bucket handle tear of the superior labrum with involvement of the insertional portion of the long head of the biceps tendon (type III); 8 cases of superior labrum tear extending within the long head of the biceps tendon (type IV). In the patients with associated disease MRI demonstrated supraspinatus tendon tear in 5 cases, lesion of the labrum also in its anteroinferior portion in 1 case, Hill-Sachs intraspongious fracture with involvement of the inferior glenohumeral complex in 1 case, and complete tear of the rotator cuff in 7 cases. Subsequent surgery always confirmed the presence of associated lesions, while the superior labrum lesion was not confirmed in 3 patients. In 4 cases, surgical findings provided a different classification of the lesion type than MRI.

DISCUSSION

In the presence of a type I anteroposterior lesion of the superior glenoid labrum, coronal MRI can depict the loss of the triangular shape of the labrum. Type II lesions show detachment of the labrum, which appears on the MR images as a high signal intensity band passing through the labrum with caudocranial orientation. A superior glenoid labrum tear with a low signal intensity area within the joint indicates a type III lesion. Complete tear of the superior glenoid labrum with involvement of the long head of the biceps tendon demonstrated on the coronal T1-weighted SE and T2-weighted GE sequences is a sign of a type IV lesion.

CONCLUSIONS

MRI can be a valuable diagnostic technique in type III and IV lesions of the superior glenoid labrum. It often provides important information about the possible presence of associated diseases, especially of the rotator cuff, which are helpful for treatment planning.