by By Nikhil N. Verma, MD

Glenohumeral instability is a common, complex problem presenting to the orthopaedic surgeon.  Most commonly, traumatic shoulder instability occurs in an anterior direction and once nonoperative management fails to improve the patient’s symptoms, surgical stabilization is indicated.  Over the last ten to fifteen years, surgical techniques have evolved from traditional open repair to all arthroscopic procedures.  Arthroscopic techniques offer several advantages over open repairs including preservation of the subscapularis insertion, decreased peri-operative morbidity and improved cosmesis.  With advances in surgical techniques and instrumentation, current data indicates that outcomes following all arthroscopic stabilization mirror those reported after traditional open repair.  This article will discuss modern arthroscopic techniques for shoulder stabilization using the BIORAPTOR◊ Knotless Suture Anchor.  Advantages of this technique include:

• No requirement for knot tying improves the speed and efficiency of the repair
• Ability to adjust tension of suture independent of anchor insertion
• Suture is tightly secured within the base of the anchor minimizing risk of suture slippage
• Use of a knotless anchor minimizes suture material within the glenohumeral joint which may cause articular injury or capsular irritation
  

	Pre-Operative Evaluation In most situations, patients present to the surgeon with a report of shoulder instability including either subluxation or dislocation.  A thorough history should be obtained including the history of the initial event (mechanism of injury, arm position and need for subsequent reduction) as well as number of recurrences.  In most cases, patients present with symptoms associated with instability events only, although labral tears may be suspected in young patients with chronic shoulder pain after trauma even in the absence of instability complaints.  A complete physical examination is performed including range of motion, strength testing, and specific instability maneuvers such as an anterior apprehension test and posterior “jerk” test.  Finally, neurovascular status must be obtained and documented. Plain radiographs should be obtained and evaluated to identify bony patterns of instability such as anterior-inferior glenoid rim fracture or defect, or Hill Sachs lesion.  In most cases, an MRI or MR Arthrogram is used to evaluate the labrum, capsule and rotator cuff.  In cases where significant bone involvement is suspected, a CT scan with 3D reconstruction is most helpful to quantify the size of the defect for appropriate pre-operative planning.  With larger glenoid defects involving more than 20-25% of inferior glenoid width, bony reconstruction in addition to soft tissue repair must be considered. In most cases, a first time dislocation is managed conservatively with gradual range of motion followed by progressive strengthening and return to normal activities, although some authors have advocated surgical management of an initial dislocation in military recruits or young, contact athletes.  In most cases, surgical management is indicated in cases of recurrent symptomatic subluxation or dislocation, or persistent pain despite appropriate conservative management.
Figure 1	Patient Positioning and Set-Up The procedure can be performed in either the beach chair or lateral decubitus positions.  My preference is to use the lateral position for a number of reasons.  First the lateral position allows lateral traction on the proximal humerus providing improved exposure to the inferior quadrants of the glenoid.  Second, the lateral position places the surgeon at the head of the table allowing easy access to the anterior and posterior aspect of the shoulder.  Finally, a lateral traction arm can be used eliminating the need for an assistant to provide distraction. Positioning is carried out using a bean bag positioning device, with care to place an auxiliary roll, to appropriately position the neck and to pad the opposite upper extremity and lower extremities.  The arm is prepped and draped and placed into a lateral traction device such as the Spider Limb Positioner (Figure 1).
Figure 2 Figure 3	Portals Four standard portals are used during arthroscopic shoulder stabilization and allow access to any point on the glenoid.  A standard posterior portal is placed first, approximately one centimeter distal and one centimeter medial to the posterolateral corner of the acromion.  This portal is used primarily for visualization.  Next, an anterosuperior portal is placed high in the rotator interval, just posterior to the long head biceps tendon.  A 5 to 6mm threaded CLEAR-TRAC◊ COMPLETE cannula is used in this portal, primarily for suture management.  A second mid-glenoid anterior portal is placed just above the superior edge of the Subscapularis using an 8.5mm CLEAR-TRAC◊ COMPLETE cannula to accommodate a curved suture passing device. (Figure 2) Finally, a posterior-inferior or 7 o’clock portal is placed approximately four centimeters distal to the posterolateral corner of the acromion to access the inferior and posterior quadrants of the glenohumeral joint when needed.  (Figure 3) This portal can be used for percutaneous anchor insertion or a 7 to 8.5mm CLEAR-TRAC◊ COMPLETE cannula can be placed to accommodate suture passing instrumentation.
Figure 4 Figure 5	Diagnostic Arthroscopy and Preparation The first step in the procedure is to perform a standard diagnostic arthroscopy paying close attention to the labrum, capsule and bony architecture of the glenoid and humerus.  Bone loss is commonly encountered during shoulder stabilization and in most cases can be managed using soft-tissue repair alone.  However, in cases where bone loss exceeds 20-25% on the glenoid side, or 30% on the humeral side, the surgeon should consider a bone reconstruction procedure. Once the labral tear is identified, the first step is to mobilize the labrum and prepare the glenoid neck to create a favorable biologic environment for healing.  In most cases, the labrum will be scarred in a medialized position.  Viewing with the scope in the anterosuperior portal, a Bankart elevator is placed in the anterior-inferior portal and complete mobilization of the labrum is performed. (Figure 4) It is critical that the labrum is mobilized completely to allow anatomic reduction to the glenoid rim.  A good rule of thumb is that the labrum and capsular tissue should be mobilized until the surgeon can visualize the muscular fibers of the subscapularis along the anterior glenoid neck. (Figure 5) Next, a DYONICS◊ BONECUTTER◊ shaver or burr is used to lightly decorticate the anterior glenoid neck and rim to create a bleeding bed for healing.  Care should be taken to avoid excessive bone resection.  Finally, a rasp can be used to create bleeding of the labrum and capsular tissue to facilitate soft-tissue healing.
Figure 6	Labral Repair and Capsular Plication When planning the repair strategy for anterior shoulder stabilization, it is critical to recall that the shoulder does not dislocate in a straight anterior direction, but rather translates in an anterior-inferior direction.  This creates a zone of injury which occurs in a 180° arc from the 2 o’clock to 8 o’clock position for the right shoulder (or 4 o’clock to 10 o’clock for the left shoulder).  Therefore it is critical to appropriately manage the labrum in the anterior, inferior and posterior-inferior quadrant.  With the scope in the antero-superior portal, the inferior and posterior labrum and capsule are inspected.  In most cases, two suture plication stitches are placed at the 6:30 and 7:30 position for a right shoulder.   If the labrum is intact and normal, a suture alone can be placed using a curved ACCU-PASS◊ Suture Shuttle via the 7 o’clock portal.  A one centimeter bite of capsular tissue is taken with the suture then passed under the intact labrum to be used as an anchor.  If the labrum is damaged or torn, a BIORAPTOR◊ Suture Anchor placed at the glenoid rim should be used to assure adequate fixation. Given the inferior location of this portion of the repair, in most cases a conventional anchor is used with knot tying performed after sutures are passed. Once the posterior-inferior repair is completed, the arthroscope is switched back to the posterior viewing portal.  Next, the repair suture is placed using a curved ACCU-PASS◊ Suture Shuttle (Figure 6).  The suture passer is introduced through the cannula in the midglenoid portal, and the tip is positioned perpendicular to the capsule approximately one centimeter from the glenoid rim.  It may be helpful to have an assistant grasp the capsulolabral tissue from the anterior-superior portal to shift the tissue superiorly and anatomically reduce the labrum to facilitate suture positioning and passage.  The tip of the suture shuttle penetrates the capsule and then is rotated to exit under the torn labrum, and the monofilament suture is retrieved via the anterosuperior portal.  In this manner, a #2 ULTRABRAID◊ Suture is shuttled through the capsulolabral complex and into position.  With appropriate placement, this suture will serve to both plicate the capsule and repair the labrum.  In general, a one centimeter bite of tissue provides adequate placation for most repairs.  Both ends of the suture are retrieved and stored out the midglenoid portal.
Figure 7 Figure 8   Figure 9	The first anterior anchor is placed low on the anterior-inferior glenoid rim at approximately the 5:30 position (right shoulder). (Figure 7)  If the angle from the mid-glenoid portal is too acute, percutenous placement using a trans-subscapularis approach to allow perpendicular access to the anterior-inferior glenoid rim can be considered.  If a percutaneous approach is undertaken, a standard BIORAPTOR◊ Suture Anchor with pre-loaded suture should be considered to facilitate suture management, although this will require knot tying.  The drill guide for the 2.9mm BIORAPTOR◊ drill bit is placed at the corner of the junction between the anterior glenoid neck and glenoid face, approximately 1-2mm onto the articular surface and a pilot hole is prepared, sinking the drill bit until the drill chuck is flush to the insertion guide handle.  The pilot hole should be prepared slightly superior to the level of the previously passed suture to allow a superior shift of the capsule.  Next, the previously placed ULTRABRAID◊ Suture is loaded into the BIORAPTOR◊ Knotless Suture Anchor using the blue suture threader loop.  Gentle tension is maintained on the suture as the anchor is passed down the cannula and positioned at the mouth of the pilot hole.  The anchor should be rotated to position the eyelet parallel to the direction of suture passage for ease of sliding, and the anchor is impacted into place to the depth of the laser line on the inserter shaft.  Next the sutures are tensioned independently while the repair is assessed visually to confirm appropriate capsular tension and apposition of the labrum to the glenoid margin.  Once tensioned, sutures can be stored in the slots on the insertion handle.  Once adequate tension is achieved, the knob on the insertion handle is turned until clicking from the torque limiter is heard confirming the suture is locked in place.  At this point, the sutures are removed from the storage slots and the insertion handle is disengaged from the anchor and removed.  An arthroscopic suture cutter is then used to cut the suture flush with the articular margin.  Once the first anchor has been placed, additional BIORAPTOR◊ Knotless Suture Anchors are placed in the same manner until the labrum is completely repaired (Figure 8).  In general, between three and five anchors are used for a standard unidirectional stabilization. (Figure 9) Each suture is passed, each anchor is placed, and the suture tensioned and cut before moving on to the next anchor.

Technique Pearls and Pitfalls
Appropriate portal position is critical to allow access and visualization to the entire glenoid.  Use spinal needle localization to position the cannulas in exacting fashion and consider the use of the guidewire and cannulated switching sticks provided with the BIORAPTOR◊ Knotless Suture Anchor system. 

When preparing the labrum, placing the camera through the anterior superior portal allows direct visualization along the anterior glenoid neck for appropriate mobilization and bone preparation.  This can be done by removing the scope sheath from the posterior portal.  Rather, remove the camera from the sheath leaving the sheath in place.  Have your assistant place their finger over the sheath opening to prevent fluid extravasation.  Place the camera alone through the anterior-superior cannula to allow visualization.  Labral preparation is critical and the capsulolabral tissue must be fully mobilized to allow anatomic retensioning and reduction to the glenoid rim.  Again, the labrum should be released from the glenoid rim until the muscle fibers of the subscapularis can be visualized. 

When placing anchors in the most inferior aspect of the glenoid between the 5 - 7 o’clock positions, consider percutaneous placement to allow perpendicular access to the glenoid face.  Again use a spinal needle to template the appropriate trajectory.  Next make a stab wound in the skin and using the BIORAPTOR◊ drill guide with a sharp tip trocar, place the guide percutaneously through the incision into the joint.  Take care to avoid damage to the articular surface with the sharp point of the trocar.  Once the guide is visualized within the joint, it can be positioned appropriately on the glenoid rim and the anchor inserted using standard techniques. 

Anchors must be placed in the appropriate position at the intersection of the glenoid articular cartilage and native bone of the glenoid neck.  Anchors should be placed 1-2mm onto the articular face to achieve proper positioning.  Avoid anchor placement medially along the glenoid neck which will lead to non-anatomic repair of the labrum and increase risk of failure.  Similarly, anchors placed too far onto the face of the glenoid will result in significant damage to the articular surface and compromise soft tissue healing.

Post-Operative Care
At the completion of the procedure the patient is placed in an arm sling.  Passive range of motion is initiated at the first post-operative visit with external rotation at the side to 30° and forward flexion to 120°.  Care should be taken to avoid any excess stretch on the anterior capsule in external rotation.  The sling is discontinued at four weeks post-op and active range of motion is initiated and advanced as tolerated with avoidance of end-range stretch.  At twelve weeks, range of motion can be normalized and strengthening is initiated.  Non-contact sports are allowed at four months with unrestricted overhead and contact sports activities at six months following surgery.