Before the use of shoulder arthroscopy and magnetic resonance imaging (MRI) in the diagnosis and management of shoulder problems, glenoid labrum lesions were underappreciated. More specifically, superior labrum lesions about the insertion of the long biceps tendon were typically noted or managed using standard open surgical techniques. An improved understanding of the surgical anatomy and the biomechanical contributions of the superior labrum have demonstrated its significance in shoulder stability and its role in the pathogenesis of shoulder pain.
Andrews et al published a study that examined glenoid labrum lesions related to the long head of the biceps (LHB) in 73 throwing athletes.
The authors observed that the LHB was contiguous with the superior labrum and that most of these patients had avulsed the anterosuperior labrum off the glenoid in conjunction with the biceps tendon. Subsequently, Snyder et al defined the pattern of superior labral injury in 27 patients who were described as having superior labrum anterior posterior (SLAP) lesions.
The authors described the SLAP lesion as a labral detachment originating posterior to the long biceps insertion and extending anteriorly. These lesions were subsequently categorized as types I-IV, as follows:
See the list below:
Type I: The glenoid labrum demonstrates degenerative changes and fraying at the edges but remains firmly attached to the glenoid rim. No avulsion of the biceps tendon is present (see the image below, upper left).
Type II: Degenerative changes and fraying are present in type II lesions. The glenoid labrum is detached completely from the anterosuperior to the posterosuperior glenoid rim. This portion of the labrum is lifted by the long biceps tendon, and the attachment of the biceps tendon is unstable (see the image below, lower right).
Upper left – Type I superior labrum anterior posterior lesion. Lower right – Type II superior labrum anterior posterior lesion.
Type III: With type III lesions, the free margin of the superior labrum is displaced into the joint (bucket handle), whereas the labral attachment to the glenoid rim and biceps tendon remains intact. The insertion of the biceps tendon is not unstable (see the image below, upper left).
Type IV: The superior portion of the labrum is displaced into the joint (bucket handle) in type IV lesions. In contrast to type III tears, the long biceps tendon is also affected, involving partial rupture in the direction of the fibers (see the image below, lower right).
Upper left – Type III superior labrum anterior posterior lesion. Lower left – Type IV superior labrum anterior posterior lesion.
Superior labral pathology is now recognized as a potential sources of considerable pain and disability in active patients. The goal of this article is to familiarize the reader with the anatomy, pathophysiology, diagnosis, and management of labral tears of the superior glenoid.
Related Medscape Reference topics:
Superior Labral Lesions [in the Orthopedic Surgery section]