What is a labral tear?

What is a Labral Tear?

A labral tear is an injury to the fibrocartilaginous ring (labrum) that surrounds and deepens the socket of either the shoulder (glenoid labrum) or hip (acetabular labrum) joint, serving to anchor joint capsule and ligaments while providing stability to the joint. 1

Anatomical Structure and Function

The labrum is a specialized fibrocartilage structure with distinct regional variations in morphology, particularly in the superior and anterior regions of the shoulder. 1 In the hip, the acetabular labrum functions similarly to deepen the socket and enhance joint stability. 2

Common Locations and Patterns

Shoulder Labral Tears

• Posterior labral tears are the most common, constituting 74% of all labral tears, contrary to historical teaching that emphasized anterior pathology. 3
• Anterior tears account for only 25.7% of labral injuries, with isolated Bankart lesions being relatively rare. 3
• SLAP lesions (Superior Labrum Anterior to Posterior) involve the superior labrum and the proximal insertion of the long head of the biceps tendon, with SLAP II being the most frequent subtype. 1
• Ten distinct tear patterns exist: including 90° tears (anteroinferior, posteroinferior, posterosuperior), 180° tears (anterior, posterior, inferior, SLAP), 270° tears (anteroinferior, anterosuperior), and circumferential (360°) tears. 3

Hip Labral Tears

• Most hip labral tears occur in the anterior quadrant of the acetabulum (59%) and are typically associated with other intra-articular pathology. 4

Causes and Mechanisms

• Shoulder tears result from: single trauma (60% of cases), repeated microtrauma, shoulder instability (particularly Bankart lesions anteriorly and Kim's lesions posteriorly), and internal impingement (Walch's postero-superior lesions). 1, 3
• Hip tears are secondary to: femoroacetabular impingement (FAI), trauma, dysplasia, capsular laxity, and degeneration. 2
• Dislocation is the most common traumatic mechanism at 31.4% of traumatic cases. 3

Clinical Presentation

Shoulder Symptoms

• Posterior labral tears predominantly cause pain (68% of cases) rather than instability (21%). 3
• Anterior labral tears predominantly cause instability (62.5%) rather than pain alone (22%). 3
• Anterosuperior labral tears without biceps involvement represent a subtle, difficult-to-diagnose cause of shoulder pain that is often missed on preoperative evaluation. 5

Hip Symptoms

• Patients typically present with anterior hip or groin pain, occasionally radiating to the buttock or thigh, with a history of hip catching or locking. 2
• The anterior hip impingement test is the most consistent physical examination finding. 2

Diagnostic Imaging

Shoulder

• MR arthrography is the reference standard for labral imaging with sensitivity ranging from 86% to 100% for detecting labral injury due to optimal glenohumeral joint distention and improved soft tissue contrast. 4
• In acute post-traumatic settings, MRI without contrast may be preferred when a post-traumatic joint effusion is present to provide sufficient visualization. 4
• CT arthrography provides comparable sensitivity and possibly improved specificity for labral lesions, with better visualization of osseous abnormalities like glenoid rim fractures, but is inferior for assessing rotator cuff tears. 4
• Preoperative diagnostic accuracy is poor: both radiologists and surgeons accurately diagnosed the tear pattern preoperatively in only 30% of cases. 3

Hip

• MR arthrography is superior to CT arthrography and noncontrast MRI for evaluation of hip labral tears in most published data. 4
• Diagnostic intra-articular injections are safe and useful for confirming the hip as the etiology of pain. 4

Clinical Pitfall

The wide variety of labral tear patterns and the high incidence of posterior shoulder labral pathology (which presents primarily with pain rather than instability) means that clinicians should not assume anterior pathology or instability as the default presentation—posterior tears are actually more common and manifest differently. 3 Additionally, preoperative imaging interpretation has low accuracy (30%), so arthroscopic evaluation remains the gold standard for definitive diagnosis. 3