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Shoulder Injuries

Anterior Dislocations: Bankart or Anterior Labral Tears

The most common type of shoulder dislocations occur when the head of the humerus slides out of the glenoid socket anteriorly, or towards the front. These injuries usually happen as a result of trauma, typically when the arm and elbow are forced above and behind the patient's head. The shoulder will then be locked and extremely painful, and then requires manipulation to relocate or "pop back in" the joint. Lesser variations of dislocations when the humerus only partially dislocates and can be self-reduced are referred to as subluxations, rather than dislocations. Patients shouldn't confuse the term shoulder separations, which involves the end of the clavicle (collar bone) at the acromioclavicular (AC) joint, with true glenohumeral joint dislocations.

Shoulder Joint Anatomy

Initial treatment of a first-time anterior shoulder dislocation in a young (under 25 years of age)  is a somewhat controversial topic.  The rate of recurrent dislocations in this population after conservative treatment with sling immobilization and subsequent physical therapy in some studies have been reported to be as high as almost 70%.  Immobilization with the arm rotated out to the side in external rotation seems to somewhat decrease the incidence of future dislocations, but this certainly hasn't been a panacea for treatment.  There has therefore been an increasing trend by surgeons to get more aggressive with first time dislocators and proceed with initial arthroscopic repair of the damaged joint. Early studies on follow-up with this form of treatment are suggesting recurrence rates in the order of 3 to 5%.

What's the damage?

When the shoulder dislocates anteriorly, the humeral head is forced violently out of the socket. The joint capsule and ligaments of the front of the shoulder are put under significant tension, and either have to stretch out, or more commonly pull so hard on the labrum where they insert that the labrum detaches from the anterior glenoid bone surface. In describing the extent of the labral tearing, surgeons refer to the glenoid as if it is the face of a clock, and it is not unusual to see anterior labral detachments extending from 1 o'clock to 5-6 o'clock (referring to a right shoulder).

Normal Labral Anatomy (Left)
Labral Tear (Right)

 
The labrum often doesn't heal from this injury satisfactorily, and because the ligaments all insert into the labral cartilage, they are effectively loosened by the displacement. Surgery is focused on repairing the labrum back onto the glenoid rim, thereby restabilizing the joint.
 

Arthroscopic View of Anterior Labral Tear
Labral Tear Extending Inferiorly
 

Arthroscopic Repair: the Details

When surgery is indicated, the AOSM team takes advantage of the latest arthroscopic techniques and instrumentation to repair the labrum while minimizing trauma and scarring to the remainder of the shoulder itself. The labral repair procedure is done as an outpatient procedure that typically requires only 3 separate quarter-inch skin punctures. In general, the procedure is broken down into the following steps:

  • Preparing the Repair Site

After inserting two small working cannulas in the front of the joint to allow easier passage of instruments and sutures through the surrounding joint soft tissues, the labral tear is fully mobilized off of the glenoid.  This allows full access to preparing the glenoid rim, as well as allows the retracted labrum to be advanced to the appropriate position.  Usually with anterior dislocations the capsule and ligaments have stretched somewhat, so it's usually best to advance the labrum in an upwards direction (counterclockwise in a right shoulder) as well as restoring it back to the glenoid rim.

A rasp or a high speed bur is then used to fully remove any scar tissue, soft tissue, or debris from the bony glenoid rim.  This also serves to provide a fresh, bleeding base which will promote better labral healing.

Labral Elevation and Rim Preparation
 

  • Suture Anchor Insertion

In the past, the challenge of repairing labral tears was finding a way to securely reattach the labrum to the bony lip of the glenoid.  The invention of suture anchors has essentially eliminated that problem and opened the door for successfully being able to reattach the labrum arthroscopically. These anchors are rigid devices that are inserted into the bone of the glenoid and lock within the bone just below the surface.  Strong, non-dissolving sutures are attached to the anchors and these are then passed around the labrum and tied to securely and effectively reattach the labrum. There are a variety of different materials these suture anchors are made of, including metal, bioresorbable material, non-resorbable inert plastic (PEEK), or combinations of different biomaterials.

Anchor Placement and Capsule Advancement
 

  • Suture Passing

Once the anchors have been securely inserted, a limb of suture must then be passed around the labrum along with a portion of the ligaments and capsule so as to gather the tissue that is going to be secured against the glenoid.  This is done using a suture passing instrument that is essentially a curved large needle with an internal loop of suture that can be passed within the hollow core of the passer and thereby serves to retrieve one of the limbs of the sutures from the anchor. This is then pulled back through the cannula to retrieve the fixation suture in preparation for tying.

Arthroscopic Suture Passer
 

  • Knot Tying

When the pair of suture limbs have been appropriately placed, they are then tied together with a single simple-throw knot or a sliding knot outside of the joint.  An arthroscopic knot pusher is then used to slide the knot down onto the labral tissue just as one would use their finger to tighten a ribbon on a gift wrapping. Repeated throws are then slid down on top of this 4 to 5 times to securely lock the knot before cutting the excess suture limbs.

Labral Anchors Tied Down
 

  • Process Repeated

For an anterior labral tear, the first suture anchor placed is at the lower portion of the tear, which in the above example of the right shoulder is at about 5 o'clock.  The sutures of this anchor are placed below the actual anchor, however, more in the 6 o'clock position, so that the restraining tissue and labrum are effectively advanced upward as they are brought back onto the bone.  This is the most important stitch for effectively tightening up the joint.  The process is then repeated with typically two more suture anchors, and these suture limbs are placed directly across from the anchor itself to simply secure the labrum and capsule firmly against the front of the glenoid without advancement.

Final Repair

Final Repair of Labrum Arthroscopic View
 

Post-op

After the arthroscopic instrumentation is removed, the 3 small incisions are closed with dissolving stitches.  A dressing is applied and the patient is then placed in a shoulder immobilizer as well as a cold cuff.  Patients usually follow up in the office 5 or 6 days after the procedure and begin physical therapy within two to 4 weeks depending on the extent of the tear and the quality of the repair felt at the time of the surgery.  Return to sports depends on the patient, the activity desired, as well as a number of other factors, but patients should expect to be out of contact sports for at least 4 months.