Multidirectional Instability/Hyperlaxity of the Glenohumeral Joint



Fig. 4.1
The view from posterior demonstrates the anterior shifting of the humeral head on the glenoid with minimal force in this right shoulder



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Fig. 4.2
In this view from the posterior portal, the widening of the rotator interval can be visualized in this lax patient


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Fig. 4.3
In many cases, the muscle fibers of the rotator cuff can be visualized through the very thin atrophic capsule


The attachment of the anterior and posterior capsule to the humerus should be visualized looking for capsular splits, perforations, or HAGL lesions (Fig. 4.4).

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Fig. 4.4
The capsule may also split or avulse from the humeral side in these patients as seen in this view from anterior




4.7 Treatment of the Lax Capsule


The lax capsule is best managed by plication sutures. The basic principle is a superior shift of the capsule while also plicating the capsule to increase its strength. Absorbable or nonabsorbable sutures may be used. The choice of suture is up to the individual surgeon. Common choices include PDS 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, used with no suction, works well. Alternatively, a synovial rasp can be used to roughen up the capsule. The capsule can be left in situ or it 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. 4.5a). The entire capsule is then advanced superiorly until the capsule appears taut (usually the 7 o’clock position- Fig. 4.5b). 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 the articular margin at that point (Fig. 4.5c). 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 the labrum, or, in some systems, the permanent suture can be passed. If a PDS has been passed, it can simply be tied (Fig. 4.5d). As the suture is tied, take care to ensure the post-limb of the suture is the limb that is through the capsule so that the knot is placed away from the articular surface. We 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.

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Fig. 4.5
(ae) In capsular plication, a suture hook is passed through the more inferior and lateral capsule (a). The hook is then advanced superiorly to take a second bite of the capsule, creating a plication of the capsule (b). The hook is then placed under the labrum, between the labrum and the bone to provide a solid anchor point for the suture (c). The suture, once the passage is completed, can then be tied to begin the process of capsular shift and repair (d). These steps can be repeated and the capsule plicated and shifted until the shoulder becomes stable (e)

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.

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 7 o’clock position) the same way as for the anterior procedure. Continue superiorly along the length of posterior glenoid until all capsular redundancy is eliminated.

In many cases of 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 g spinal needle superiorly near the capsular insertion into the humerus. A suture is threaded through the needle into the joint. 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-retrieving device is then 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 then 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 utilized to blindly grab the suture 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. These steps are repeated until sufficient laxity has been eliminated. In most cases 2–4 sutures will be required (Fig. 4.6).

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Fig. 4.6
The capsule may be too thin posteriorly for plication, in which case sutures are placed through both the capsule and overlying infraspinatus tendon to provide stability to the posterior aspect of the shoulder

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 (Fig. 4.7a, b). In order 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. 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-retrieving 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 may be incorporated, or the device can simply grab the middle glenohumeral ligament. The suture passed percutaneously is then grabbed and pulled out the anterior cannula. 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 used to blindly grab the suture from the subacromial space and retrieve it out the anterior cannula as well. A sliding locking knot is used to close the interval. 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. One must be 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.
Dec 2, 2017 | Posted by in ORTHOPEDIC | Comments Off on Multidirectional Instability/Hyperlaxity of the Glenohumeral Joint

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