MR imaging in the evaluation of SLAP injuries of the shoulder: findings in 10 patients.

OBJECTIVE

Injuries to the superior portion of the glenoid labrum, called SLAP (superior labrum, anterior and posterior) injuries, are recently recognized injuries consisting of tears of the long head of the biceps tendon anchor/superior labral complex. The purpose of this study was to determine if the MR imaging findings in patients with surgically proved SLAP injuries correspond to the abnormalities found at arthroscopy.

MATERIALS AND METHODS

Four variants of SLAP lesions have been described; they are based on the degree of compromise of the superior portion of the glenoid labrum, biceps tendon, and labral-biceps anchor. A type I lesion has superior labral fraying in the region of the biceps anchor. A type II lesion has superior labral fraying and stripping of the superior part of the glenoid labrum and attached biceps off the underlying glenoid fossa. A type III lesion has a bucket-handle tear of the superior portion of the glenoid labrum in the region of the biceps anchor. A type IV lesion has a bucket-handle tear of the superior part of the glenoid labrum with extension of the tear into the proximal biceps tendon. Standard spin-echo MR imaging studies in 10 patients with surgically proved SLAP lesions were evaluated retrospectively. Correlations were made between MR imaging findings and the SLAP injury type determined from descriptions in the surgical report. MR imaging studies in a control group of seven symptomatic patients surgically proved not to have SLAP injuries also were evaluated.

RESULTS

MR imaging examinations of two patients with type I lesions showed irregularity of the labral contour and a slight increase in signal intensity on all imaging sequences. MR imaging examinations of two patients with type II lesions showed globular high signal interposed between the superior part of the glenoid labrum and the superior portion of the glenoid fossa. One case showed high signal in the labral-biceps anchor. The other case showed paired cleavages in the superior and inferior aspects of the superior part of the glenoid labrum at the labral-biceps anchor. MR imaging examinations of two patients with type III lesions showed superior labral tears identified as high signal intensity within the superior part of the labrum separate from the normal superior part of the labral cavity. MR imaging examinations of the four patients with type IV lesions showed diffuse high signal intensity within the superior part of the glenoid labrum with marked abnormal high signal intensity extending into the proximal high signal intensity within the superior part of the labrum separate from the normal superior part of the labral cavity. MR imaging examinations of the four patients with type IV lesions showed diffuse high signal intensity within the superior part of the glenoid labrum with marked abnormal high signal intensity extending into the proximal biceps tendon. None of the MR imaging studies of patients in the control group showed findings seen on MR imaging studies of patients with surgically proved SLAP lesions.

CONCLUSION

Although prospective data are required to document accuracy, these preliminary data suggest that an MR examination can be useful in detecting SLAP abnormalities and establishing the type of SLAP lesion before surgery, thereby permitting better operative planning.