Adult Reconstruction, 1st Edition

Section III - Shoulder Reconstruction

Part B - Evaluation and Treatment of Shoulder Disorders

35

Surgical Management of Traumatic Unidirectional and Atraumatic Multidirectional Instability

Xavier Duralde

The indication for surgical management of glenohumeral instability is a failure of conservative treatment modalities. The goal of surgery is to reconstruct glenohumeral anatomy in a balanced fashion avoiding excessive tightening in any one direction, in other words, to obtain a stable yet mobile shoulder without causing stiffness. Pathoanatomy will vary from case to case, so a versatile treatment strategy is necessary allowing adjustment of operative technique based on the pathology encountered. Instability presents in an extremely variable fashion from one patient to another as mentioned in previous chapters and is associated with various pathologic lesions.

The commonly described ends of this spectrum are TUBS (traumatic unidirectional instability due to a Bank-art lesion that typically requires surgery) and AMBRI (atraumatic multidirectional instability that is often bilateral and treated with rehabilitation or inferior capsular shift when conservative treatment fails).

Significant overlap occurs between these two groups, and surgical planning must take this into account. As arthroscopic techniques improve, a larger percentage of these operations may be performed arthroscopically, but the principles of treatment remain the same whether the surgery is performed open or arthroscopically. The surgeon should strive to identify all pathoanatomy based on history, physical examination, radiographic studies, evaluation under anesthesia, and diagnostic arthroscopy. Surgery can then be performed to repair all damaged structures and re-establish balanced stability of the glenohumeral joint.

Wide variation currently exists in the orthopaedic community regarding the definition of multidirectional instability.¹ This diagnosis is overestimated if it is based on laxity testing alone. Neer and Foster² first reported on the results of the inferior capsular shift for multidirectional instability in 1980, describing a group who had uncontrollable, involuntary inferior subluxation or dislocation associated with both anterior and posterior dislocations or subluxations of the shoulder. These patients had both signs and symptoms of instability in all three directions. Unfortunately, many patients with unidirectional or bidirectional instability with associated asymptomatic laxity of the shoulder in another direction have been lumped into this extreme category. The balanced surgical approach described in this chapter can be successfully adapted irregardless of the degree of instability encountered, but in the severely affected group described by Neer and Foster, a modified rehabilitation program may be in order to allow greater time for soft tissue healing.

Benefits of Arthroscopy

As in other areas of shoulder pathology, arthroscopy has greatly increased the surgeon's diagnostic and therapeutic capabilities.³ A careful diagnostic arthroscopy prior to instability repair allows the surgeon to identify all pathology contributing to the patient's instability.⁴Bankart lesions have been reported in combination with superior labral tears⁵ as well as significant stretching of the glenohumeral joint capsule.⁶,⁷ Failure to identify and treat all contributing pathology may lead to failure of the instability repair.⁸,⁹ Some lesions such as superior labral tears are best treated arthroscopically, emphasizing the importance of arthroscopic evaluation even if open instability repair is planned. Other cited advantages of arthroscopic instability techniques include lower morbidity, decreased pain, shorter surgical time, improved cosmesis, and better maintenance of motion postoperatively.³,¹⁰ The degree to which

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these theoretical advantages apply will vary from surgeon to surgeon depending on his or her own level of experience with arthroscopic surgical technique. Currently arthroscopy does have its limitations, with higher failure rates reported in cases of significant glenoid bone loss (<25% loss of inferior glenoid).⁹,¹¹,¹² Modern arthroscopic techniques with suture anchors are well suited to manage labral pathology,¹³ whereas cases involving humeral avulsions of the glenohumeral ligaments (HAGL lesion), capsular insufficiency following previous surgery,³ and multidirectional instability due to diffuse capsular laxity may be better suited to open techniques. In cases in which the surgeon cannot achieve stability with arthroscopic techniques, he or she should not hesitate to proceed with an open instability repair.

Surgical Options

Wide variability exists in both the spectrum of pathologic lesions causing shoulder instability and surgical techniques available to address pathology. Patients with traumatic shoulder instability most commonly have a Bankart lesion whereas the hallmarks of atraumatic instability are a redundant capsule and a widened rotator interval.¹⁴ Although traumatic instability is generally unidirectional, atraumatic instability is generally bidirectional or multidirectional and can occur because of congenital laxity, repetitive microtrauma to the shoulder, or traumatic events superimposed on pre-existing laxity.¹⁵ As long as the surgeon understands that significant overlap exists in these patient groups and is ready to treat all encountered pathology, a successful surgery can be planned and expected.

Currently, arthroscopic techniques are ideal for management of labral pathology such as Bankart lesions and can be adapted to treat associated capsular and rotator interval pathology. Recent reports on suture anchor techniques have shown comparable results to open Bankart repairs.¹⁶ The open inferior capsular shift offers a versatile and highly effective approach to diffuse capsular laxity and has significant advantages over other described open techniques. The capsular shift procedure described by Neer can be modified to adjust the tightening of the capsule depending on the amount and location of laxity in a particular shoulder. It can be modified for unidirectional, bidirectional, or multidirectional instability.¹⁴ The inferior capsular shift is designed to reduce capsular volume on all sides including anterior, inferior, and posterior through a single approach. It allows overlapping and therefore reinforcement of tissues in the direction of greatest instability with tightening of the capsule inferiorly and on the opposite side. This procedure also avoids asymmetric tightening, which can lead to abnormal joint mechanics and a fixed subluxation in the opposite direction.¹⁷ The operation is laterally based to allow for greater volume decrease than medially based or centrally based techniques because the glenohumeral joint capsule is a laterally based, truncated cone.¹⁸ This approach also allows treatment of associated labral avulsions anteriorly and rotator interval closure. It does not allow adequate exposure of the superior labrum, and diagnostic arthroscopy is beneficial prior to open surgery to allow visualization of the superior labrum and arthroscopic superior labral repair if needed arthroscopically.

For these reasons, the technique for the open inferior capsular shift will be described for the treatment of atraumatic instability and the arthroscopic Bankart repair using a suture anchor technique will be described for the treatment of traumatic instability. Although these techniques are by no means the only procedures recommended for the treatment of shoulder instability, they are both versatile and effective and afford surgeons the ability to adapt their techniques to all encountered pathology.

Operative Technique

Anesthesia

Instability repair can be performed under interscalene regional anesthesia, general anesthesia, or a combination of both. The interscalene block provides pre-emptive analgesia as well as excellent postoperative analgesia and has been proven to be reliable and safe.¹⁹ Its shortcomings include the fact that the posterior shoulder (posterior arthroscopic portal) and axilla are not adequately covered by the block and require the addition of local or general anesthesia. In addition, the pectoralis major is not completely included, and tension in this muscle may limit exposure during deep dissection in open repairs. For arthroscopic techniques, muscle paralysis is generally not required although it is helpful for open approaches. This author uses a combination of general anesthesia and interscalene block for all instability repairs. A laryngeal mask airway is generally used in arthroscopic cases unless airway issues require the use of an endotracheal tube. In open cases, an endotracheal tube is used so that muscle paralysis can be used to relax the pectoralis major.

Patient Positioning and Setup

Both arthroscopic and open instability repairs can be performed in the beach-chair position. In open cases, the torso is placed at a 30-degree angle to the floor. This position allows easy access to the axilla if an axillary skin incision is to be used and offers excellent access to the inferior pouch. The trunk is placed more vertically in arthroscopic cases to allow easier access to the posterior shoulder. In arthroscopic cases, the beach-chair position allows easy conversion to open surgery if necessary. Distraction of the humeral head away from the glenoid is most easily achieved, however, in the lateral decubitus position with traction on the arm and the weight of the patient's dependent body as countertraction. In the beach-chair position, distraction of the glenohumeral joint for improved arthroscopic visualization runs the risk of displacement of the patient's body off the operating table. In these cases, the patient's torso can be tied to the operating table, using a sheet to prevent displacement. A neurosurgical headrest is helpful with either approach to allow better access to the shoulder.

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Examination under Anesthesia

Examination under anesthesia serves to clarify the direction and degree of instability. This rarely contradicts the preoperative diagnosis but may be helpful, especially in muscular patients who guard on examination in the office. It is also helpful in defining the primary area of instability. The surgeon must be careful to relocate the humeral head in the glenoid prior to each maneuver to maintain a frame of reference. Translation of the humeral head over the glenoid rim is abnormal in any direction. With the arm at the side, the sulcus test in neutral will demonstrate laxity in the superior portion of the glenohumeral capsule including the superior glenohumeral ligament as well as the rotator interval. This is also indicative of an enlarged inferior pouch. Failure of the sulcus sign to improve significantly by placing the shoulder in an externally rotated position is indicative of incompetence of the rotator interval tissue as this should normally tension in external rotation. With the arm in 90 degrees of abduction and neutral rotation, the shoulder can be gently forced anteriorly and posteriorly to test the laxity of the inferior glenohumeral ligament and the anterior and posterior capsule. Crepitus on dislocation and relocation is suggestive of labral pathology. If the humeral head locks out of joint, this is suggestive of a Hill-Sachs lesion.

Diagnostic Arthroscopy

The diagnostic arthroscopy is of great benefit in identifying pathologic lesions contributing to the patient's shoulder instability whether an arthroscopic or open technique of repair is planned. A standard posterior portal is established in the soft spot, and a 30-degree arthroscope is used to perform a systematic evaluation of the glenohumeral joint. Placement of the anterior portal must be carefully planned as two anterior portals are required for arthroscopic instability repair. For the diagnostic arthroscopy, an 8-mm cannula can be placed anterosuperiorly through the rotator interval adjacent to the glenoid and labrum. This allows space for later placement of an additional cannula (usually 5 mm) farther inferiorly and laterally, which enters the rotator interval laterally at the triangular convergence of the supraspinatus and subscapularis tendons. Areas of concern include the articular surfaces, the labrum, the capsule, and the rotator cuff and biceps tendons.

The humeral head is carefully inspected for a Hill-Sachs lesion posterosuperiorly. Burkhart and DeBeer¹¹ have described a method to determine arthroscopically how much anteroinferior glenoid bone is missing in the case of a bony Bankart lesion. Bone loss >25% of the glenoid would be an indication for open bone grafting. Secondary degenerative changes of the articular surfaces owing to chronic instability or large chondral lesions from an acute traumatic dislocation can be documented as these may affect prognosis.

The labrum must be evaluated circumferentially both by visual inspection and tactile examination with a probe. The superior labrum may normally be meniscoid, with the diagnosis of a torn labrum reserved for cases with fraying and granulation. A torn superior labrum can generally be elevated off the glenoid rim by 1 cm. Anteriorly, the labrum may be detached and clearly visible or it may be healed along the anterior glenoid neck (anterior labroligamentous periosteal sleeve avulsion lesion, or ALPSA lesion).²⁰ In this latter case, the anteroinferior glenoid appears bare with the capsule attaching medially on the glenoid neck. This lesion must be identified so that the labrum can be elevated and reduced back onto the rim of the glenoid.

The capsule is inspected for signs of stretching, midsubstance tearing, or tearing from its humeral insertion (HAGL lesion). The drive through sign describes the ability to easily push the arthroscope between the humeral head and glenoid, passing the scope from the back to the front of the glenohumeral joint. The drive through sign indicates capsular laxity, and if it persists following arthroscopic labral repair, suggests a concomitant capsular stretching, which may require further capsular imbrication or open repair.

Undersurface rotator cuff injuries may be associated with glenohumeral instability, and arthroscopy allows identification and treatment. The biceps anchor may be involved with superior labral tears and is readily identified arthroscopically.

Open Inferior Capsular Shift

The crux of the capsular shift procedure is adequate release of the capsule far enough inferiorly and posteriorly to allow obliteration of the inferior pouch and any associated posterior capsular laxity. Understanding and performing several key maneuvers are critical to success and should help give the surgeon confidence with this operation. Proper takedown of the capsule is critical to avoid bisecting the inferior pouch. The capsular insertion inferiorly on the medial humeral neck is broad and somewhat variable anatomically.²¹ Safe techniques with release of both the superior capsular reflexion and the more inferior capsular insertion under direct vision are critical in avoiding potential injury to the axillary nerve. Simple guidelines are available to determine the amount of capsular release and amount of shift needed in each individual case.

For the open inferior capsular shift, a neurosurgical headrest is used to allow the assistant access to the superior shoulder. A short arm board is built up with sheets to maintain arm position anterior to the anterior axillary line (Fig. 35-1). Local anesthesia is infiltrated in the axilla and the posterior portal site as these areas are not adequately covered by the interscalene block. The table back is elevated to position the trunk at a 30-degree angle to the floor, and the table is placed in reverse Trendelenburg during the diagnostic arthroscopy. The table back is then returned to the 30-degree position for the open portion of the case. This maneuver precludes the need to readjust the headrest between the arthroscopic and open portions of the procedure.

The skin incision is made in the deltopectoral interval for muscular men and typically measures 10 cm in line between the coracoid and axillary fold.²² In thin women, a 5- to 6-cm axillary incision can be made in the skin folds. The axillary skin folds can be marked with a needle scratch prior to draping, which allows the incision to be hidden.

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Skin flaps are elevated from the inferior rolled border of the pectoralis major to the clavicle with either incision. A needle-point cautery is useful for careful dissection while allowing hemostasis. The deltopectoral interval is then developed using blunt and sharp dissection taking the cephalic vein laterally. The clavipectoral fascia is incised along the lateral border of the conjoined tendon, and this structure is retracted medially. Excessive traction on this structure is avoided to prevent damage to the musculocutaneous nerve. The subacromial and subdeltoid bursal adhesions are released, and the terminal branch of the posterior humeral circumflex vessel is cauterized as it passes between the deltoid and proximal humerus just lateral to the bicipital groove. The anterior humeral circumflex vessels are ligated using no. 0 polyester sutures. This allows access to the inferior portion of the capsule and has not been associated with avascular necrosis. The sutures are placed 1 cm apart so that the vessels can be cauterized in between and released. Care must be taken to not grasp the joint capsule with the medial suture as this will not allow the subscapularis to be separated from the capsule in later dissection.

The inferior veil of the coracoacromial ligament is released sharply to the level of the ligament itself to allow clear visualization of the rotator interval. The deep dissection is begun with an incision of the subscapularis tendon 1 cm medial to the lesser tuberosity. The superficial two-thirds of this tendon are dissected off of the capsule using blunt and sharp dissection. Typically, a pointed Adson clamp is used to spread the subscapularis fibers, and these are cut with a long-handled no. 15 blade. The thickness of the subscapularis can be determined by opening the rotator interval and palpating the thickness of the tendon so that the superficial two-thirds can be reliably peeled off of the underlying capsule while leaving some tendinous tissue attached to the capsule for reinforcement. During the inferior portion of this dissection, the axillary nerve must be palpated and protected. The tug test, as described by Flatow, is useful to localize the nerve.²³The surgeon passes the index finger of the inside hand along the subscapularis muscle beneath the conjoined tendon. With the outer hand, the surgeon palpates the axillary nerve on the undersurface of the deltoid muscle lateral to the humerus. By gently tugging back and forth with two hands, the surgeon can be sure which medial structure is indeed the axillary nerve. The ability to tug the nerve medially and feel tension on it laterally assures the surgeon of continuity of the nerve through the axilla. The inferior portion of the subscapularis has a very muscular insertion onto the capsule. This can be released using electrocautery, and the plane between the subscapularis and the capsule clearly visualized from this inferior portion of the approach. The needle-point cautery is used to carefully cut through most of the subscapularis thickness inferiorly until just a few muscle fibers are visible overlying the capsule. These last few fibers are released using a blunt elevator (a rounded blunt Cobb-like elevator is preferred). This elevator can then be passed medially gently to define the plane between the capsule and the subscapularis tendon. The tendon dissection off the capsule can then proceed both from a medial-to-lateral and a lateral-to-medial direction. It is important to free all subscapularis fibers off of the capsule so that the capsule is free to be shifted and not tethered by the subscapularis muscle. This also allows a Bankart repair to be performed more easily if this is required. If subscapularis fibers are left attached to the capsule medially at the level of the glenoid, visualization for passage of sutures during the open Bankart repair will be obscured. Suturing the subscapularis to the capsule with the Bankart sutures can potentially tether the subscapularis and limit motion. After release of the subscapularis, the capsule can be clearly visualized.

Capsular release begins at the level of the rotator interval. The capsule is transected 5 mm medial to the stump of subscapularis tendon. This leaves enough capsule laterally to anchor the repair later during capsular reconstruction. Traction sutures are placed in the medial limb of the capsule during this maneuver. At the inferior border of the subscapularis insertion, it is critical to deviate the incision in the capsule in a hockey stick fashion laterally along the neck of the humerus, essentially vertical and parallel to the line of the humerus. This avoids amputation of a portion of the inferior pouch. The axillary pouch is now palpated to determine its size. The pouch does have a variable pattern of insertion on the anatomic neck of the humerus. The periosteum and broad capsular insertion are incised vertically along the anterior humerus just distal to the most inferior aspect of the subscapularis stump. Inferior to subscapularis tendon, the entire capsule can be released from the humerus without leaving a lateral cuff as capsular repair will not require suture placement that far inferiorly. The vertical portion of the capsular and periosteal release

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is carried to the level of the latissimus dorsi tendon. An elevator can then be used to elevate the capsule off the medial anatomic neck, placing the elevator just inferior to the articular reflection of the capsule. This allows any capsular reflection adjacent to the articular surface (usually superior to the elevator) to be incised under direct vision without risk of damage to the axillary nerve. Flexion and external rotation will bring that portion of the neck of the humerus into the surgical field and allow the capsule to be released from the humerus under direct vision. This arm position also reduces tension on the axillary nerve and allows it to fall away from the inferior pouch. Additional traction sutures are placed into the margin of the capsule as more capsule is liberated from the humerus. The more inferior portion of the capsular insertion (that part inferior to the elevator) is cut under direct vision with scissors just superior to the latissimus dorsi tendon. This dissection can be carried posteriorly to the level of the posterior band of the inferior glenohumeral ligament if needed. The amount of capsular release and amount of shift required will vary from patient to patient. Guidelines for capsular release are the following. The capsule should be released from the anatomic neck of the humerus until traction on the anterior capsule obliterates the inferior pouch and also eliminates posterior subluxation of the glenohumeral joint with the arm in neutral rotation. These two observations at surgery indicate that the inferior and posterior pouches are adequately tightened by anterior tension to allow for a balanced reconstruction of the shoulder joint capsule.

At this point, a humeral head retractor (usually a Fukuda ring retractor) is inserted and the anterior labrum is carefully inspected. If a Bankart lesion is noted, it can be repaired at this time. The labrum is freed from the anterior glenoid neck, and the glenoid neck is debrided down to bleeding bone. This can be done with a curette, osteotome, or burr. This creates a fresh bleeding bed for healing of the labrum. Suture anchors are generally placed on the rim of the glenoid between the equator and most inferior point of the defect depending on the amount of labrum avulsed. The labrum is shifted superiorly with the sutures to afford a medial as well as lateral shift with this procedure. Both suture limbs can be brought underneath the labrum and out of the capsule, tying the knots extra-articularly. If the patient has a hypoplastic labrum and the labral repair does not create an adequate bumper, a no. 2 polyester suture can be placed parallel to the glenoid through the labrum from approximately the 5 o'clock to the 3 o'clock position to create a purse-string type imbrication of the labrum in that location. Palpation of the Bankart repair should demonstrate a firm bumper of the labrum at the location of the repair.

It is critical to understand that a capsular shift cannot be effectively performed if the labrum and capsule are not attached to the glenoid. A Bankart lesion must be repaired prior to performing the capsular shift. Once the labral repair is performed, a T cut can be made in the capsule obliquely along the superior border of the inferior glenohumeral ligament (IGHL). Scissors are generally used to cut the capsule. This T cut can also be performed prior to the Bankart repair to help exposure. The IGHL is usually visible, but in patients with hypoplastic ligaments, the capsular incision should proceed obliquely superiorly to end at the equator of the glenoid. This capsular incision generally passes anterior to the labrum, and the labrum should not be incised.

The shift portion of the procedure is now begun. The amount of shift performed will vary from case to case and will depend on the amount of capsule released, degree of capsular redundancy, and the arm position selected for reattachment of the capsule. Deep retractors are now removed, and for the average patient, the arm is positioned in approximately 30 degrees of abduction and 30 degrees of external rotation for performance of the capsular shift. In overhead throwing athletes, this position can be adjusted even up to 80 degrees of external rotation and abduction to allow for greater mobility in the abducted/externally rotated position. The 30/30 position, however, is the most common recommended position. The first step of capsular repair involves placement of two sutures of no. 0 polyester at the lateral aspect of the rotator interval superiorly. These are placed prior to repair of the inferior pouch to avoid having to position the arm in extension to visualize this area following repair of the inferior portion of the capsule. These sutures will be later passed through the superior margin of the superior limb of the capsule both to close the lateral aspect of the rotator interval and to anchor the superior portion of the capsule as it is pulled over the inferior capsule to complete the capsular reconstruction. With the arm in 30 degrees of abduction and external rotation, the inferior capsule is then pulled superiorly as far as possible and is repaired to the lateral stump of capsule using multiple no. 0 polyester interrupted figure-of-8 sutures (Fig. 35-2). The

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amount of shift possible will vary from patient to patient, customizing the repair to that particular patient's degree of instability. The superior limb of the capsule is then repaired to the rotator interval using the previously placed polyester sutures. The superior limb of the capsule is then pulled in a vest-over-pants fashion over the inferior limb and is sutured laterally to the stump of capsule using multiple no. 0 polyester interrupted figure-of-8 sutures. The two limbs of the capsule are then sutured together medially (Fig. 35-3). The subscapularis is now repaired anatomically using no. 0 polyester interrupted figure-of-8 sutures back to the stump of subcapularis left laterally. The continuity of the axillary is verified using the tug test. Routine deltopectoral closure and skin closure are then performed. Suction drainage is generally not required.

Arthroscopic Bankart Repair

The pathology and surgery will be described in reference to a right shoulder.

Patient Positioning

This operation can be performed in either the beach-chair or the lateral decubitus position. The lateral decubitus position has the advantage of easier joint distraction without tying up an assistant or running the risk of displacing the patient's torso off the table. If the beach-chair position is used, some type of restraining device to hold the patient's torso firmly to the operating table is recommended to avoid pulling the patient off the table. We generally use a combination of general anesthetic and interscalene block for patient comfort both during and after the procedure, but paralysis is not required for the arthroscopic procedure. Three arthroscopic portals are required for arthroscopic Bankart repair, one posterior and two anterior portals. The posterior portal is made in the soft spot centrally in the posterior aspect of the glenohumeral joint. One anterior portal should be placed to allow an 8-mm cannula to enter the joint along the most medial and superior aspect of the rotator interval into the joint. The second anterior portal is placed laterally and slightly inferior to the first but not so inferior that the cannula is aimed superiorly. This cannula will be used to drill holes and pass suture anchors into the glenoid rim. Inferior orientation of this cannula facilitates placement of the 5 o'clock anchor anteroinferiorly. A 5-mm cannula is placed through this portal, entering the rotator interval at its most lateral apex. A diagnostic arthroscopy is performed to visualize all damaged structures. The Bankart lesion classically presents as an avulsion of the labrum from the 3 o'clock to approximately the 6 o'clock position. The labrum must be carefully inspected circumferentially, however, as superior labral tears are commonly seen in association with an anteroinferior labral avulsion. The status of the biceps and rotator cuff are also carefully inspected. The posterior aspect of the humeral head is carefully evaluated for the presence of the Hills-Sachs lesion. The anterior labrum is often healed along the anterior neck of the glenoid and may not therefore be visualized on initial arthroscopic inspection. Presence of the ALPSA lesion can be confirmed by looking at the anterior glenoid neck through one of the anterior portals. An arthroscopic elevator is placed through the more superior medial portal while the surgeon views from posterior, and the displaced labrum is then elevated sharply off the anterior neck of the glenoid. This will allow the labrum to float laterally and lie adjacent to the rim of the glenoid. A 5.5-mm full-radius resector is then used to debride the anterior glenoid neck down to bleeding bone. This creates a good healing surface for labral repair.

The labrum will be repaired to the rim of the glenoid using 3-mm bioabsorbable suture anchors. Two or three suture anchors are typically used at the 5 o'clock, 4 o'clock, and 3 o'clock positions along the anteroinferior glenoid rim. Metal suture anchors are also acceptable.

It is critical that the labrum be repaired up onto the rim of the glenoid to re-establish the anteroinferior “bumper” and deepen the socket to increase the concavity compression effect of the shoulder.¹³ To achieve this, anchors must be placed either on the apex of the glenoid rim or slightly onto the face of the glenoid. Anchor placement on the anterior glenoid neck will not allow the labrum to be repaired to its anatomic position and may result in recurrent instability postoperatively.⁹ Just as in the open Bankart repair, a superior shift of the labral tissues is desirable during repair. A traction suture through the labrum will assist in achieving this shift prior to placement of suture anchors. This technique described by Boileau and Ahrens²⁴ consists of passing a traction suture through the labrum via the superior portal using either a Caspari-type punch or a suture shuttle. This suture is then placed outside the superior medial cannula and is used as a traction suture to pull the labrum superiorly. This allows the suture shuttle to pass sutures from the anchors more inferiorly through the labrum. If significant capsular laxity is noted along with the Bankart lesion, more

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capsule can be grasped with the suture shuttle to create a shift of tissue medially and superiorly while simultaneously making the labrum more bulky by the addition of capsular tissue. Specific guidelines for the amount of shift of capsular tissues needed during arthroscopic repair are not as well defined as they are for open inferior capsular shift. The surgeon can view inferiorly while tension is applied to the traction suture to determine how much of a shift is needed to obliterate the inferior pouch. There are no reports available to judge the efficacy of this technique. The first anchor is placed at the 5 o'clock position directly onto the rim of the glenoid via the more inferior-lateral cannula. The drill cannula is tapped with the mallet to secure its position on the rim of the glenoid. The drill hole is made to the depth of the drill stop, and the 3-mm bioabsorbable anchor is tapped into place. One suture limb is then grasped and retrieved out the anteromedial cannula. A 90-degree cannulated suture hook is then placed through the more anteromedial cannula and is used to pass a suture shuttle through the labrum inferior to the position of the suture anchor while tension is applied via the traction suture. This shuttle is retrieved using a suture grasper via the more inferior lateral portal and is used to pass the one suture limb in that cannula back through the labrum (Fig. 35-4). One suture limb then passes directly from the anchor out through the superior cannula while the second suture limb passes through the labrum and out through the superior cannula. The labrum can now be secured at this location using a sliding knot. This sliding knot is best tied via the more inferior lateral portal as it is in line with the anchor. The post of the sliding knot is the suture limb passing through the labrum itself as this will more reliably keep the knot off the articular surfaces (Fig. 35-5). Suture anchors are now placed at the 4 o'clock and 3 o'clock positions, and these steps are repeated to create a bumper of labrum along the anteroinferior glenoid rim (Fig. 35-6). The normal sublabral foramen superior to the 3 o'clock position should not be closed as this will not enhance the repair and will lead to a loss of external rotation. The most difficult anchor to place and suture to pass is the first. The next two suture anchors are relatively straightforward.

Superior Labral Repair

If a superior labral anterior to posterior (SLAP) tear is noted, an additional anchor can be placed at the 1 o'clock position easily through these two cannulas. The surgeon must be cautious in placing the 1 o'clock anchor because the most superior cannula is relatively medial and the drill must be aimed medially to avoid penetrating the glenoid face. Again, one suture limb can be pulled out the inferior cannula. A bird-beak tissue penetrator can be passed through the superior cannula and through the labrum grasping the suture limb that is passing out the inferior cannula. This suture is then pulled back through the labrum, and a sliding knot is again used for repair. The 11 o'clock suture anchor posterosuperiorly can usually be reached using the aforementioned cannulae. If not, a midlateral portal can be established using a spinal needle as a guide, and a 5-mm working cannula is placed directly through the rotator cuff to allow access to the 11 o'clock position posterosuperiorly. The glenoid neck superiorly in the area of the SLAP lesion is debrided

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down to bleeding bone. The 3-mm bioanchor is placed in a similar fashion to the previous anchors. One suture limb is grasped out an anterior portal. The 90-degree cannulated suture hook is placed through the anteromedial cannula and is used to pass the suture shuttle through the labrum just posterior to the biceps anchor. This shuttle is retrieved out the midlateral cannula and is used to pass the suture through that cannula through the labrum. Both sutures are retrieved out the midlateral cannula, and a sliding knot (using the suture limb through the labrum as the post) is used to secure the labrum.

Postoperative Rehabilitation

The vast majority of patients following open or arthroscopic instability repair can begin an identical postoperative rehabilitation program. The exception to this is the patient with true multidirectional instability who had signs and symptoms of true instability in all three directions preoperatively and who had an extremely patulous capsule of questionable quality at the time of surgery. That particular patient will benefit from a brace postoperatively holding the arm in neutral rotation to protect both the anterior and posterior capsule evenly and supporting the arm to avoid inferior subluxation for the first 6 weeks following surgery. Patients with instability this extreme rarely develop stiffness following capsular reconstruction, and this type of delay will allow for more scar tissue formation in the capsule.

The main difference between arthroscopic and open repairs involves the detachment of the subscapularis tendon and the subsequent need for its protection in the early postoperative period. Protection of the capsular and labral repair in these two patient groups, however, is identical and requires greater restrictions than those typically needed for the protection of the subscapularis alone. Following open repair, patients are cautioned for the first 6 weeks to avoid lifting >5 pounds, avoid excessive external rotation outside the treatment protocol, and avoid using the arm to get up from a seated position. The act of pushing oneself up from a seated position with the arm in the internally rotated position places significant stress on the subscapularis and should be avoided during the first 6 weeks following open surgery. Other than these few restrictions, the therapy protocol is identical for both groups (Table 35-1).

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Results

Neer and Foster first described the inferior capsular shift procedure in 1980² and reported uniformly satisfactory results in a series of 40 patients with multidirectional instability. A follow-up series of 100 additional patients in 1990 revealed similar results.¹⁴ Pollock et al.²⁵demonstrated the versatility of this procedure with 94% excellent and good results in a series of patients with unidirectional and bidirectional instability. Multiple other authors have subsequently shown the procedure's reliability sometimes with slight modification in technique.⁷,²⁵,²⁶,²⁷,²⁸,²⁹,³⁰ Good and excellent results are noted routinely in approximately 90% of patients with recurrent instability ranging from 4% to 11% postoperatively. Although 70% to 90% of athletes return to play following open inferior capsular shift surgery, elite overhead athletes have only about a 50% chance to return to play at the same level.

Current arthroscopic techniques of Bankart repair using suture anchors have demonstrated results equal to open techniques and are laying to rest the notion that arthroscopic techniques are unreliable for instability surgery.¹⁶ Although older techniques using bioabsorbable tacks and transglenoid techniques were not as reliable as open Bankart repair,³¹ newer series reporting on suture anchor techniques routinely demonstrate good and excellent results between 91% and 95%.⁴,⁸,¹²,³²,³³,³⁴ Fabricciani et al.¹⁶ reported no recurrences in a prospective series of 60 patients, half of whom were treated with open Bankart repair while the other half were treated arthroscopically. Better final range of motion was noted in the arthroscopic group, supporting one of the major theoretical advantages of this arthroscopic technique. Recurrent instability has been reported ranging from 0% to 11% with this arthroscopic technique. Return to sports ranges between 74% and 100%,⁴,¹²,³²,³³ but overhead athletes still have more difficulty in returning to sport at the same level of play, with results between 55% and 68% reported.⁴,³³ Glenoid bony defects greater than 25% to 30% remain a significant cause of failure⁹,¹¹,¹² and are an indication for open repair and bone grafting.

Summary

The two extremes in the spectrum of instability include traumatic unidirectional instability, usually associated with labral pathology such as a Bankart lesion, and atraumatic multidirectional instability, usually associated with capsular laxity. Glenohumeral instability is a spectrum with significant overlap in presentation and pathologic lesions contributing to the problem. The surgeon must be able to identify all pathoanatomy contributing to the instability through a careful preoperative and intraoperative evaluation. Surgery is reserved for failure of conservative management, but when performed, should address all pathology contributing to the instability. The capabilities of arthroscopy are expanding continuously, and current arthroscopic techniques have been proven equal to open techniques for Bankart repair, the usual lesion of traumatic instability. Inferior capsular shift enjoys similar success in treating the usual lesions of atraumatic instability, a patulous capsule, and widened rotator interval. Successful management with arthroscopic or open procedures depends on identification of pathology, adequate mobilization and balanced repair of tissues, protection of the axillary nerve, and a safe rehabilitation program that allows adequate healing time for the repaired tissues. Current contraindications for the arthroscopic technique include glenoid bone loss >25% and an inability to repair capsular avulsions or defects. Each surgeon should use techniques with which he or she feels comfortable to achieve the above stated goals for successful management of either traumatic or atraumatic glenohumeral instability.

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