Conservative Management

Nonsurgical management is the initial treatment of choice for MDI. This program must be no less than 6 months in duration and include an emphasis on proper scapular control at all times to allow the new motor skill and coordination to become permanent. If this extensive process fails and abnormal firing patterns of the shoulder girdle continue, the patient may be a candidate for surgical intervention.

An adequate therapy program is first centered on the scapular stabilizers, using bracing, taping, and isometric exercises. It is extremely important to stress to the patient, family, and physical therapist that stabilization of the scapula must precede any attempts at rotator cuff strengthening. Starting rotator cuff exercises without stabilizing the scapula with bracing, taping, or manual control will result in increased irritation and magnification of the pain. Once stabilization is achieved, the focus of rehabilitation progresses to the rotator cuff, attempting first to correct abnormal muscle firing patterns and then improve deficient proprioceptive mechanisms and restore functional ability.

Arthroscopic Treatment

Arthroscopic Capsular Shift

Arthroscopy offers several advantages over open surgery in the management of MDI. The ability to detect injuries and abnormalities under magnification extends our diagnostic capability and allows direct repair of abnormal or injured structures on all sides of the joint. Diagnostically, one can obtain an overview of the joint, detecting the presence of labral tears, capsular tears, and capsular and rotator interval laxity. Although the surgeon will already know the direction of the instability by the history and physical examination, with the patient awake and under anesthesia, repeating the examination while visualizing the movement with the arthroscope in the joint is useful (Fig. 13-1). The usual advantages of arthroscopy include preservation of muscle attachment, better visualization of pathology, anatomy-specific repairs based on this visualization, and small incisions. Patients usually experience less pain postoperatively by virtue of the minimally invasive nature of the procedure.

FIGURE 13-1 This view from the posterior portal demonstrates the anterior shifting of the humeral head on the glenoid with minimal force in this right shoulder.

An interscalene block and catheter are routinely used for intraoperative and postoperative pain relief. This should be placed under ultrasound guidance and with the help of a nerve stimulator to avoid complications by an anesthesiologist with experience in regional anesthesia. Several methods are used today.^10,11 Because of reported complication rates, avoid intra-articular pain pumps, but an indwelling interscalene catheter is currently thought to be acceptable.

Once adequate anesthesia, positioning, prepping, and draping have been carried out, the diagnostic arthroscopy can begin. The lateral decubitus position offers an ergonomic advantage when doing labral and capsular reconstructions of the shoulder; however, if one has no experience with this position, the beach chair position can be used. The diagnostic arthroscopy should begin with the standard posterior portal at the horizon of the glenohumeral joint. Several areas need to be evaluated, including the anterior capsule (Fig. 13-2), inferior capsule or axillary pouch (Fig. 13-3), posterior capsule (Fig. 13-4), rotator interval (Fig. 13-5), labrum, and rotator cuff. In some patients with MDI, the posterior capsule may so thin that the muscle of the infraspinatus can be visualized through it (Fig. 13-6).

FIGURE 13-2 This view from the posterior portal demonstrates the lax anterior capsule in this right shoulder in the lateral decubitus position.

FIGURE 13-3 This view from the posterior portal of a right shoulder demonstrates the laxity of the inferior capsule that is the hallmark of MDI.

FIGURE 13-4 This view from the posterior portal demonstrates the lax posterior capsule and absent posterior inferior glenohumeral ligament that is another hallmark of true MDI.

FIGURE 13-5 This view from the posterior portal of a right shoulder in the lateral decubitus position demonstrates the widening outward bulging and clear stratification of the tissues of the rotator interval.

FIGURE 13-6 In many cases of MDI, the posterior capsule is so thin that the muscle of the infraspinatus and teres minor can be visualized through the capsule.

The attachment of the anterior and posterior capsule to the humerus should be visualized, looking for capsular splits, perforations, or humeral avulsion of glenohumeral ligament (HAGL) lesions (Fig. 13-7).

FIGURE 13-7 A, Note the split in the middle of the anterior capsule that occurred in this MDI patient participating in competitive athletics. B, Note the multiple perforations in this damaged left shoulder. C, The view from the anterior portal demonstrating the complete detachment of the posterior capsule from the humeral head, a reverse HAGL lesion.

Treatment of the Lax Capsule

The lax capsule is best managed by plication sutures. Absorbable or nonabsorbable sutures may be used. The choice of suture is up to the individual surgeon. Common choices include PDS (polydiaxonone) sutures or one of many permanent suture materials.

The initial step involves abrading the capsule to stimulate a healing response. A full-radius shaver, without teeth and used without suction, works well. Alternatively, a synovial rasp can be used to roughen up the capsule. The capsule can be left in situ or can be cut at its attachment to the labrum. A suture hook is then used to perforate the capsule approximately 1 cm from the labrum. The area to be initially penetrated is determined by the amount of capsular laxity. A standard approach is to draw an imaginary line parallel to the horizon of the glenoid toward the capsule. This is the point of entry for the suture hook into the capsule. For a left shoulder, the anterior capsule is addressed as follows. The first suture hook is placed in the capsule at the 6 o’clock position at the point of the imaginary line and rotated until it pierces the capsule (Fig. 13-8A). The entire capsule is then advanced superiorly until the capsule appears taut (usually the 7 o’clock position; see Fig. 13-8B). This is the point of advancement of the first suture. The same suture hook is then used to penetrate the labrum at the junction of the labrum and articular margin at that point (see Fig. 13-8C). A shuttle relay or some other monofilament suture is threaded through the suture hook. This suture is used to shuttle the final suture through both the capsule and labrum or, in some systems, the permanent suture can be passed. If a PDS suture has been passed, it can simply be tied around the suture tail that will be retrograded. As the suture is tied, take care to ensure that the post limb of the suture is the limb passing through the capsule so that the knot is placed away from the articular surface. I prefer a sliding self- locking (modified Roeder) knot. All knots have a tendency to migrate toward the articular margin as they are being tightened, so you must be cognizant to push the knot away as the suture and capsule are tightened. This advances the capsule superiorly and medially.

FIGURE 13-8 A, In this view of a right shoulder from the posterior portal, the inferior capsule is penetrated by a suture hook in preparation for capsular plication. B, The hook is then moved superiorly at least 1 “hour” and then placed between the labral bone junction (left to right). C, The suture is then passed through both the capsule and labrum and tied arthroscopically, plicating the capsule. D, The posterior capsule is plicated in similar fashion, as demonstrated in this view from the anterior portal.

These steps are repeated up the face of the glenoid. The second capsular stitch is placed often at the 7 o’clock position and advanced until it is taut, which is usually near the 8 o’clock position on the glenoid. Additional sutures are placed in a similar manner up the glenoid face until the entire anterior capsular laxity is eliminated (Fig. 13-9).

FIGURE 13-9 This view of a finished anterior inferior capsular plication for MDI shows the restoration of the anterior band of the inferior glenohumeral ligament.

The posterior capsule is addressed in a similar way. For a left shoulder, start at the 6 o’clock position and shift the capsule superiorly until it is taut (usually around the 5 o’clock position) using the same technique described for the anterior procedure (see Fig. 13-8D). Continue superiorly along the length of posterior glenoid until all capsular redundancy is eliminated (Fig. 13-10).

FIGURE 13-10 A, The lax posterior capsule has been rasped and the suture hook is preparing to penetrate the distal end of the valley of the loose capsule. B, The suture hook is advanced through the tissue and the superior shift is initiated. C, The suture hook is advanced and placed between the labrum and bone of the glenoid. D, The suture is advanced through all the plicated structures in preparation for repair. E, The sutures are then tied, creating a capsular tuck.

Often in MDI, the posterior capsule is insufficient to hold a plication suture. In these cases, one may use a suture plication technique that includes the infraspinatus tendon. For this technique, the lateral capsule is pierced percutaneously with a large-lumen, 18-gauge spinal needle inferiorly near the capsular insertion into the humerus (Fig. 13-11A). A suture is threaded through the needle into the joint (see Fig. 13-11B). The initial stitch should be around the 7 o’clock position for a right shoulder and the 5 o’clock position for a left shoulder. The suture coming through the needle is grasped and the spinal needle is removed. A suture retrieval device is used to pierce the capsule adjacent to or just under the labrum, grasping the percutaneously placed suture. It is then removed out the posterior portal. The cannula is retracted until it lies just outside the infraspinatus tendon. Using a switching stick, the cannula is placed into the subacromial space. A crochet hook is used to grab the suture blindly while watching from inside the joint. One should see the cannula indenting the infraspinatus during this retrieval. This suture is tied and the degree of capsular tightening is assessed (Fig. 13-11C). These steps are repeated until sufficient laxity has been eliminated. In most cases, two to four sutures will be required.

FIGURE 13-11 A, The tendon and capsule may be plicated together in the posterior aspect of the shoulder. A spinal needle is advanced along the posterior cortex of the humerus and through the infraspinatus tendon and the lateral capsule. B, A lead suture is placed through the spinal needle and then retrieved through the medial aspect of the capsule and infraspinatus muscle. C, Both the capsule and tendon have been rasped in preparation for suture tightening. The suture is retrieved and tied blindly in the subacromial area to plicate the posterior capsule and infraspinatus tendon.

The arthroscope is then placed posteriorly above the level of the reconstruction and the rotator interval is assessed. In cases of MDI, true closure of the rotator interval is required to complete the stabilization of the shoulder. To tighten both the inner and outer layers of the rotator interval, a spinal needle is placed into the joint percutaneously approximately 1 cm from the articular margin, just anterior to the edge of the supraspinatus tendon (Fig. 13-12A). A suture is threaded through the needle into the joint and placed anteriorly for retrieval. The anterior cannula is then retracted out of the joint until it is just anterior to the subscapularis tendon and the outer layer of the rotator interval. A suture retrieval device is placed through the anterior layer of the rotator interval tissue and through the capsule entering the joint. The upper border of the subscapularis tendon should be incorporated in true MDI cases. The suture passed percutaneously is then grasped and pulled out the anterior cannula (see Fig. 13-12B). A switching stick is then used to pass the cannula around the subscapularis tendon into the subacromial space. The cannula should be seen indenting the supraspinatus from inside the joint; it is then retracted until the indention is just anterior to the suture. A crochet hook is to blindly grasp the suture blindly from the subacromial space and retrieve it out the anterior cannula as well (Fig. 13-12C). A sliding locking knot is used to close the interval (see Fig. 13-12D). Additional sutures may be needed and are placed in the same manner. Work progressively more medially with each additional stitch. Alternatively, one may look in the subacromial space to retrieve and tie the suture, being careful not to incorporate the coracoacromial ligament into the rotator interval closure. When you see minor internal rotation of the arm, there has been adequate closure of the rotator interval.

FIGURE 13-12 Technique of true rotator interval placation. A, A spinal needle is placed through the supraspinatus and superior capsule 1 cm medial to its attachment to the humeral head. B, The suture is retrieved through the subscapularis and outer rotator interval. C, The suture is blindly retrieved from the subacromial area. D, The suture is tied, plicating the rotator interval and shortening the coracohumeral and superior glenohumeral ligaments.

Treatment of the Torn Capsule and Special Techniques

Some patients with MDI may have associated labral or capsular tears, especially if they have had repeated subluxations or dislocations. In these patients, it is important to remember to address the lax capsule in addition to the torn labrum. The labrum is repaired using suture anchors, preferably double-loaded anchors. The first suture from the anchor is placed through the capsule inferior to the tear and advanced superiorly under the free edge of the labral tear. This achieves a superior capsular shift and labral repair in one step. It is a good technique to mattress the sutures for greater tissue movement when possible. The second suture from the anchor can achieve more shift of the capsule when needed, or simply be placed around the first stitch to hold the shifted tissue in place and help secure the labral tear. The placement of the anchor and suture depends on the location of the tear. Once the labrum has been re-established and the capsule has been shifted superiorly, additional capsular plication stitches can be added to shift the lax capsule further in a manner similar to what has already been described. Once the labral repair and capsular shift are completed, the rotator interval can be addressed.

If there is no labral tear, but the labrum is hypoplastic, an anchor can be inserted on the glenoid and the capsule shifted toward it by passing sutures from the anchor through the capsule. In this case, it is advisable to mattress the sutures to avoid suture irritation of the humeral head. This is also useful if there is a capsular split that needs to be addressed.

The use of a thermal device has fallen into disfavor; however, it is still used by many surgeons, with good results. There is inconsistent depth of penetration as well as tissue response and the long-term effects of intra-articular temperature extremes are unknown. This warrants caution if a heating probe is used. If used for capsular laxity, I recommend suturing around the treated area with additional sutures in the rotator interval to supplement the thermal procedure.

Wound Closure

The portals are closed with Steri-Strips only. If a larger cannula has to be used for labral repairs in addition to the capsular plication, I might use an absorbable subcutaneous stitch followed by a Steri-Strip. A sterile dressing is applied to the shoulder prior to the patient awaking from anesthesia.

Treatment Regimen

Depending on the procedure, the patient is placed in an abduction brace or a gunslinger brace. The brace is maintained full time, with the exception of showers, for 6 weeks. Initial rehabilitation efforts focus on trying to maintain correct shoulder posture while in the brace.

Each patient has a unique response to healing after surgery. In those in whom the capsular shift is healing rapidly, passive motion and scapular stabilization exercises may begin when clinically indicated, but exercises for most patients are delayed until 4 to 6 weeks postoperatively. Active exercise begins at 6 to 8 weeks, with careful attention to maintaining correct scapular position during all exercises. In patients in whom the scapula remains protracted, early dynamic bracing is initiated to retrain the scapula to remain in its correct retracted position. This may include static bracing or taping for short periods. The need to re-establish proper shoulder positioning in space at all times is vital, especially during exercise. The patient and the therapist must both be aware of this. The more quickly normal shoulder posture is re-established, the more likely a good recovery and a good result will occur.

Once the capsular reconstruction has healed, based on the clinical end point examination and progressively decreasing pain, and the patient is able to maintain correct scapular position, the therapy is progressed to include rotator cuff–strengthening exercises, proprioceptive neuromuscular facilitation exercises, and plyometrics. No passive stretching is allowed by the therapist for the first 3 months. At 4 to 8 months postoperatively, integrated rehabilitation as described by Kibler¹² is initiated, along with sports-specific conditioning in the athletic population. Sports are allowed between 6 and 12 months, depending primarily on shoulder position and tracking patterns.

Avoiding Complications

One of the most common early pitfalls is placing incorrect or inadequate portals. Be sure to use the outside-in technique to localize the placement of the portal. Take a spinal needle and insert it into the joint where you think your portal should be. Use that spinal needle to try to touch areas in the shoulder that need to be addressed. If the spinal needle can touch the areas of treatment, a good working portal will be established. Remove the spinal needle and incise the skin precisely. Insert the cannula into the joint with the same angle as the spinal needle. Alternatively, there are newer cannula systems that allow penetration with a small needle device, over which a cannulated switching stick is inserted into the joint.

High-flow infusion pump systems may be a problem in these cases because of the insufficiency of the capsule. I highly recommend the use of the lowest setting that allows good distention to prevent fluid extravasation. If the procedure takes more than 45 minutes, swelling may make the rest of it extremely difficult and taxing. Keeping the fluid flow and pressure as low as possible can help prolong the operating time.

The same risks apply to arthroscopic surgery as to open surgery. The axillary nerve is at risk in the axillary pouch. Be sure to grab separate bites of the capsule to shift it up to the labrum. One large enveloping suture could snare the axillary nerve.

If a knot is left adjacent to the articular surface, a patient may complain of clicking with shoulder range of motion. The long-term effect of this is unknown. Be sure to push the knots away from the articular surface when possible.

The most devastating complication is chondrolysis, which has been associated with thermal devices and intra-articular pain pumps.^13,14 Avoid their use to minimize risk.

Familiarity with the instruments and how they work is imperative prior to using them in surgery. Preoperative planning and mental visualization of the procedure and on models or cadavers prior to the actual operation will lead to improved repairs and better results.