What is the labrum and why does it matter?
The labrum is a rim of fibrocartilage that surrounds the edge of the glenoid socket. It deepens the socket by roughly 50 percent and creates a suction effect that helps hold the humeral head in place during arm motion.
Without the labrum doing its job, the shoulder becomes mechanically unstable. Even small forces can cause the humeral head to translate excessively within the socket, leading to pain, dislocations, and progressive cartilage damage.
Labrum tears do not heal on their own. The fibrocartilage of the labrum has poor blood supply, so once a tear forms, it stays. Many patients learn to live with small labrum tears, but tears that cause functional instability or recurrent dislocations are typically repaired surgically.
This page covers the geometry of the labrum, the common tear patterns, and why the specific location of your tear determines how you should sleep during recovery.
The glenoid socket and labrum geometry
The glenoid socket on the scapula is shallow — much shallower than the hip socket. By itself, the bony socket only holds about a quarter of the humeral head.
The labrum fills the gap. Picture a flat plate (the bony glenoid) with a rubber gasket (the labrum) attached to the rim. The gasket extends the depth of the socket and creates a snug seal around the humeral head.
The labrum is divided into regions for clinical description: superior (top), inferior (bottom), anterior (front), and posterior (back). Tears are described by which region is involved.
The biceps tendon attaches to the top of the labrum at the superior labrum. This attachment point matters because tears involving the biceps anchor have specific consequences — the most common being the SLAP tear.
SLAP tears: Superior Labrum Anterior to Posterior
A SLAP tear is a tear of the superior labrum extending from anterior to posterior. The biceps tendon is involved because it attaches at this exact location.
SLAP tears are classified into four types:
Type I: Fraying of the labrum without detachment of the biceps anchor. Usually associated with normal aging or mild overuse.
Type II: Detachment of the biceps anchor and superior labrum from the bony glenoid. This is the most common and clinically significant SLAP type.
Type III: Bucket-handle tear of the superior labrum with an intact biceps anchor.
Type IV: Bucket-handle tear of the superior labrum that extends into the biceps tendon.
SLAP tears are common in overhead athletes — pitchers, swimmers, volleyball players. They are also seen after falls onto the outstretched arm and after lifting heavy objects with a sudden eccentric load.
Surgical treatment depends on the type. Type II tears are typically repaired by reattaching the biceps anchor to the glenoid with suture anchors. In older patients or those with biceps tendon damage, the surgeon may perform a biceps tenodesis instead, which moves the biceps attachment off the glenoid to a more stable location on the humerus.
Bankart tears: anterior-inferior labrum
A Bankart tear is a tear of the anterior-inferior labrum. It is the classic injury after an anterior shoulder dislocation, when the humeral head shoots out the front of the joint and tears the labrum off the glenoid rim on its way.
Bankart tears are the single most common reason for recurrent shoulder dislocations. Once the labrum is torn, the shoulder loses its anterior containment. Subsequent dislocations require less force and become progressively easier.
The recurrence risk after a single anterior dislocation without surgical repair depends heavily on age. Patients under 25 have recurrence rates of 70 to 90 percent. Patients over 40 have rates closer to 10 to 20 percent. The Bankart repair is most often recommended in younger patients precisely because of this risk profile.
A bony Bankart is a variant where a piece of the glenoid bone has also been chipped off along with the labrum. Bony Bankart lesions are biomechanically more significant and may require techniques like the Latarjet procedure rather than soft-tissue repair alone.
Reverse Bankart: posterior-inferior labrum
A Reverse Bankart is a tear of the posterior-inferior labrum. It is much less common than the standard Bankart and occurs after posterior shoulder dislocations or repetitive posterior loading.
Posterior dislocations are often missed at initial presentation because the arm position looks more normal than in anterior dislocations. They can occur after seizures, electrocution, or a fall on a flexed and adducted arm.
Repair of a Reverse Bankart involves reattaching the posterior-inferior labrum to the glenoid. The recovery considerations are similar to standard Bankart repair, but the sleep position constraints are different because the unstable direction is posterior rather than anterior.
Posterior labrum tears in athletes
Beyond Reverse Bankart, athletes — especially weight lifters and football linemen — can develop posterior labrum tears from repetitive bench-press-style loading. These tears do not always cause frank dislocation but cause pain and clicking with posterior-directed loads.
Surgical repair is selective. Many of these tears can be managed with PT focused on scapular stability and posterior cuff strengthening. Surgery is reserved for cases with functional instability or persistent pain.
How tear location determines repair anchor placement
The surgeon places suture anchors in the bony glenoid to reattach the torn labrum. The number and location of anchors depend on the tear pattern.
A type II SLAP repair typically uses one or two anchors at the top of the glenoid.
A standard Bankart repair uses three to four anchors along the anterior-inferior glenoid rim.
A combined SLAP and Bankart repair (after a dislocation that tore both regions) may use five or six anchors.
A Reverse Bankart repair places anchors along the posterior-inferior glenoid.
Each anchor is a permanent placement. Anchors fail when the labrum tears off the suture rather than when the anchor pulls out of the bone. This is why the first 6 to 8 weeks of recovery are critical — the labrum-to-suture interface needs time to heal biologically.
Athletes vs non-athletes: repair differences
A non-athlete recovering from labrum repair primarily needs to avoid forces that strain the repair during daily life.
An athlete recovering from labrum repair has the additional requirement of returning to a sport-specific load profile. Throwing athletes need late external rotation. Overhead athletes need full elevation. Lineman need contact tolerance.
These differences extend the rehabilitation timeline. A non-athlete returns to most daily activities by month 4 to 5. A pitcher returns to full throwing by month 9 to 12, sometimes longer.
Recurrence risk by tear type
Recurrence is the failure mode that matters most after labrum repair.
After Bankart repair, recurrence rates depend on the technique, the surgeon’s experience, the patient’s age, and adherence to rehabilitation. Modern arthroscopic Bankart repairs have recurrence rates of 5 to 20 percent. Open Latarjet procedures (used for bony Bankart or recurrent failure) have rates of 2 to 5 percent.
SLAP repairs have recurrence rates of roughly 10 to 15 percent at 5 years. Biceps tenodesis as an alternative has lower failure rates in patients over 35.
Sleep position contributes to recurrence risk. External rotation during sleep strains the anterior labrum repair, increasing failure risk in the first 6 weeks. We cover anti-external-rotation positioning in detail in the labrum sleep guide.
Sources
- American Academy of Orthopaedic Surgeons (AAOS), SLAP Tears patient education.
- Mayo Clinic, Shoulder Instability and Bankart Lesions.
- StatPearls, Bankart Lesion (PubMed Bookshelf NBK).
- Provencher MT et al., Recurrence after arthroscopic Bankart repair, AJSM, meta-analysis.
About the author
By James Park. I had a labrum repair early in my shoulder journey and learned the hard way that anti-external-rotation sleep positioning is not optional in the first six weeks. This page is what I wish I had read before the surgery instead of after.
Nothing on this page replaces a conversation with your surgeon.