Lesions of the Shoulder- ALPSA Lesions

The ALPSA lesion refers to an Anterior Labral Periosteal Sleeve Avulsion. An ALPSA lesion is a torn anterior inferior glenoid labrum. The labral ligament complex is displaced medially and shifted inferiorly. The labrum is displaced by the inferior glenohumeral (IGHL) ligament and the labrum is rolled up like a sleeve with an intact anterior scapular periosteum.

ALPSA lesions are associated with a more severe injury and the labral part remains attached to the periosteum of the scapular margin and can be tethered in this abnormal location increasing the chances of further displacement and redislocation. The ALPSA may need to be repaired before it heals in an abnormal position, which will make the surgery more difficult later on.

The ALPSA lesion is different from a Perthes Lesion. A Perthes lesion is a nondisplaced avulsion of the anterior inferior labrum with medial stripping and an intact scapular periosteum.