|Year : 2007 | Volume : 1 | Issue : 1 | Page : 39-44
Arthroscopic repair of retracted adhesed rotator cuff tear is complicated by the fact that standard capsulotendinous releases seldom provide enough additional lateral excursion of the tendons for repair to bone. However, the stepwise incorporation of anterior interval slides, double interval slides, and interval slide in-continuity can dramatically increase the lateral excursion up to 5 cm., allowing for tension free repair to bone. This paper details the author’s indications and techniques for performing these releases.
Keywords: Rotator cuff, tendon repair, rotator cuff repair, interval slides
|How to cite this article:
Burkhart SS. Arthroscopic repair of retracted adhesed rotator cuff tears and subscapularis tears: The effective use of interval slide releases. Int J Shoulder Surg 2007;1:39-44
Massive rotator cuff tears demand the same initial evaluation as any cuff tear, and the foremost determination is that of tear pattern recognition. Mobile tears can be classified into either crescent-shaped tears or U-shaped tears. The crescent-shaped tears are easily reducible to their bone bed with minimal tension and can be repaired to the bone bed on the greater tuberosity with suture anchors. If there is adequate mobility, double row fixation can be used. Massive U-shaped tears, on the other hand, have minimal medial to lateral mobility but good mobility from anterior to posterior. These tears should be repaired by side to side margin convergence sutures, converging the margin of the rotator cuff to the prepared bone bed on the humeral neck and greater tuberosity so that tendon-to-bone fixation can be obtained with suture anchors. By using this principle of margin convergence, the strain at the reconfigured margin is greatly reduced. It should be noted that the acute version of a U-shaped tear is actually an L-shaped tear.
Margin convergence can be accomplished by a variety of techniques. There is a hand-off technique between two suture-passing instruments, one through the posterior leaf and one through the anterior leaf [Figure – 1].
A more rapid version involves a Viper (Arthrex; Naples, FL) technique in which a Viper suture passer or a Scorpion (Arthrex; Naples, FL) suture passer is used to pass all the sutures in the anterior leaf, followed by sequential passage of the lower limb of each suture pair through the posterior leaf with a Penetrator-type suture passer [Figure – 2].
This method allows use of the same instrument repetitively in an assembly-line manner and helps to reduce operating time. Many tears that appear irreparable initially are actually amenable to margin convergence and complete repair. In fact, oftentimes one or two side-to-side sutures will reveal the reparability of the tear that initially looks irreparable [Figure – 3].
A category of great interest is that of the immobile contracted rotator cuff tear. This represents less than 10% of all rotator cuff tears in my practice, even though a large number of these types of tears are referred to me. In a general orthopedic practice, the percentage would be considerably less. These are rotator cuff tears in which the tear margins will not reach the bone bed by standard repair and mobilization techniques. There is minimal elasticity. These tears require mobilization. In the past, when we encountered such tears, we had only rudimentary mobilization techniques and frequently had to settle for partial repairs. In many cases, these worked quite well and in a small series of arthroscopic partial cuff repairs that we have looked up, 12 patients at 36-month follow-up improved their UCLA score from 8.9 to 31.7 on average (unpublished data, Burkhart and Tehrany).
In the orthopedic literature on open techniques, Bigliani and Flatow have discussed the need for open interval slides. These procedures were based on the principle of releasing the coracohumeral ligament to increase the lateral excursion of the supraspinatus tendon. Cordasco and Bigliani popularized the open anterior interval slide, whereas Codd and Flatow suggested an open posterior interval slide as well.
An arthroscopic interval slide was first reported by Tauro. He utilized an arthroscopic adaptation of the Bigliani technique in order to release the coracohumeral ligament and contracted immobile adhesed tears. Tauro suggested a couple of different patterns of tear, but both tear patterns resulted from scarring of the tear margin to the coracoid base, with tethering by the coracohumeral ligament. His technique involved arthroscopic division of the anterior interval just anterior to the leading edge of the supraspinatus tendon. The line of this cut went just above the root of the biceps and aimed toward the base of the coracoid.
My experience has been that, with an anterior interval slide, I will gain 1-2 cm of lateral excursion of the supraspinatus and no more. With massive adhesed retracted tears, this is often not enough lateral excursion to allow apposition of the tendon to its bone bed.
We have published our technique of performing an arthroscopic double interval slide as well as the results of a small series of patients that we have followed who have been repaired by that technique. This procedure begins with an anterior interval release of the coracohumeral ligament, similar to that of Tauro [Figure – 4].
The amount of lateral excursion of the supraspinatus is then judged. If that is not enough to reach the bone bed, then we do a posterior release in the interval between supraspinatus and infraspinatus, aiming towards the base of the scapular spine [Figure – 5].
One must remember that the suprascapular nerve curves tightly around the base of the scapular spine and is protected by a fat pad. When we do this procedure, we place two traction sutures, one on either side of the posterior interval so that we can pull laterally as we cut with our arthroscopic scissors. This pulls the tendon that we are cutting further away from the nerve and is an added measure of protection for the nerve. We also stop the cut when we reach the fat pad. Furthermore, we elevate the blades of our scissors above the level of the posterior-superior glenoid neck as we cut in order not to entrap the nerve at the base of the scapular spine in the event that we inadvertently slip medially with our scissors. This has allowed us to safely release the posterior interval.
By doing this double interval slide, we typically have found that we have increased the mobility of the supraspinatus tendon by 4-5 cm of additional lateral excursion. This generally allows the tendon to be repaired directly to the bone bed on the humeral neck and greater tuberosity. Furthermore, the portion of the infraspinatus that is released gains a similar amount of lateral mobility. Because these two tendon flaps are quite floppy and difficult to control, we repair them to bone prior to placing side-to-side sutures. Once they are secured to bone, then the side-to-side sutures are placed, accomplishing the strain reduction of margin convergence [Figure – 4].
In repairing the subscapularis, one must be knowledgeable about the normal arthroscopic appearance of the subscapularis and its footprint. One must also be familiar with the normal subscapularis-biceps relationship and be able to recognize a normal versus an abnormal medial sling of the long head of the biceps. This sling is composed of components of the superior glenohumeral ligament as well as the medial head of the coracohumeral ligament.
When the upper subscapularis is torn, the biceps tendon frequently is medially subluxed., This occurs when the medial sling becomes incompetent and begins to separate from its insertion onto the lesser tuberosity of the humerus. Keep in mind that the footprint of the medial sling of the biceps is located adjacent to the footprint of the upper subscapularis and that it frequently fails in tandem with the upper subscapularis. This allows the biceps to sublux posterior to the torn upper subscapularis. Sometimes early failure of the upper subscapularis and the biceps sling, associated with subluxation of the biceps, can be very subtle and can best be determined by noting that the biceps cuts posterior to the plane of the upper subscapularis [Figure – 6].
Ordinarily, the long head of the biceps should be located anterior to the plane of the upper subscapularis.
The subscapularis footprint has been studied in the lab. In a study of 12 cadavers, we found the footprint to be approximately 2.5 cm in its superior to inferior dimension and 1.8 cm from medial to lateral at its proximal aspect. It has a wider footprint superiorly than inferiorly. In fact, it is shaped roughly like the state of Nevada [Figure – 7].
Our feeling is that the wider footprint proximally signifies that the upper subscapularis is more important in terms of force generation. Therefore, we feel that upper subscapularis tears, rather than being ignored, should most definitely be repaired.
The best portal for approaching the bone bed of the subscapularis as well as for passing antegrade sutures through the subscapularis is an anterosuperolateral portal, adjacent to the anterolateral corner of the acromion [Figure – 8].
An instrument through this portal will typically be introduced into the shoulder joint parallel to the lesser tuberosity and parallel to the subscapularis tendon. We generally use a posterior viewing portal and use a combination of 30-degree and 70-degree arthroscopes to obtain an ‘aerial’ view of the subscapularis. This optimizes our view of the subscapularis footprint. Frequently, a traction suture in the lateral aspect of the subscapularis is useful to provide counter traction during dissection of a retracted subscapularis. However, if the subscapularis is torn but not retracted, I typically will make a window in the rotator interval to determine whether there is subcoracoid stenosis.If the distance from the coracoid tip to the anterior aspect of the subscapularis is less than 7 mm, then I would do an arthroscopic coracoplasty through the window in the rotator interval. In some cases there is a PASTA type of partial-thickness tear of the subscapularis where the failure begins on the articular side. These are repaired with trans-tendon suture anchors after freshening the bone surface.
When there is a complete tear of the subscapularis with retraction, the most useful arthroscopic indicator for identifying the subscapularis is the ‘comma sign’ [Figure – 9].
The comma sign refers to a vertically oriented fibrous structure located immediately above the superolateral aspect of the subscapularis tendon. In fact, it defines the superolateral border of the subscapularis tendon so that one may then predictably dissect out the subscapularis in its proper anatomic form. Retracted tears require mobilization, and I have found arthroscopic mobilization to be very satisfactory. In fact, I find it to be better than open mobilization. One must become comfortable dissecting around the coracoid. Remember that the posterolateral aspect of the coracoid, where one works in dealing with the subscapularis, is the safe side of the coracoid. I do a three-sided release, using a combination of shaver and electrocautery to release the tendon from the coracoid neck and coracoid base, as well as using an arthroscopic elevator to release it from the arch of the coracoid neck and from the anterior glenoid neck. This is a three-sided release involving anterior, superior and posterior aspects of the subscapularis tendon. In tears that still are under significant tension after this release, I will do a medialization of the bone bed of approximately 5 mm. One should remember not to plunge inferomedial when working around the base of the coracoid. In fact, one should not go medial to the mid portion of the inferior coracoid.
Anterosuperior rotator cuff tears can be very disabling. These involve the subscapularis, supraspinatus and infraspinatus in conjunction with biceps subluxation.
These are massive tears that frequently cause loss of meaningful forward flexion and complete loss of overhead function. The order of repair is important. The surgeon should first do a biceps whip stitch and tenotomy and then get the biceps temporarily out of the way until one is ready to do the tenodesis. Secondly, an arthroscopic coracoplasty and subscapularis repair are done, followed by biceps tenodesis and then repair of the residual rotator cuff (supraspinatus and infraspinatus).
[Figure – 10]: Schematic representation of the interval slide in continuity. Anterior view of a left shoulder. (A) An anterosuperior rotator cuff tear involving 50% of the subscapularis tendon and a massive tear of the supraspinatus and infraspinatus tendons. (B) A coracoplasty is performed resecting the posterolateral aspect of the coracoid tip. The dotted box outlines the proposed area for the window of the interval slide in continuity. (C) An interval slide in continuity is performed by first exposing the posterolateral aspect of the base of the coracoid. This releases the coracohumeral ligament. Then the medial rotator interval tissue is excised, creating a ‘window’ through the rotator interval, further releasing and excising the coracohumeral ligament. Care is taken to ensure the lateral margin of the rotator interval remains intact, maintaining the continuity between the subscapularis tendon and the supraspinatus tendon. (D) After an interval slide in continuity, improved mobility of the subscapularis tendon is seen. The subscapularis tear can now be repaired to bone, leaving a U-shaped posterosuperior rotator cuff tear to be repaired. (E) The residual U-shaped posterosuperior rotator cuff tear is repaired with side-to-side sutures using the principle of margin convergence. (F) The converged margin is then repaired to bone in a tension-free manner. CHL, coracohumeral ligament.
This technique does not disrupt the tear margin and allows for mobilization of the subscapularis, along with release of the coracohumeral ligament without actually cutting the tendon margins. In this way, the cuff margin is preserved for more effective repair.
For the massive retracted anterosuperior tears, one must initially find the ‘comma sign,' which leads the surgeon to the superolateral border of the subscapularis. The subscapularis is then mobilized by means of the previously described three-sided release.
A traction stitch in the subscapularis is then used to pull the tendon laterally enough so that a window can be made in the rotator interval. The scope is brought in through that window to visualize the base of the coracoid, while the tissues at the medial aspect of the coracoid base are excised by cautery and power shaver. This allows for a complete coracohumeral ligament release to achieve maximum lateral excursion of the subscapularis. The subscapularis is then repaired to its bone footprint on the lesser tuberosity; and the ‘comma sign,’ which is composed of the medial head of the coracohumeral ligament and the superior glenohumeral ligament, is available for further repair by margin convergence if need be. A biceps tenodesis is performed using a BioTenodesis screw (Arthrex; Naples, FL). The sutures from that tenodesis construct are preserved for reinforcing the lateral row of the rotator cuff repair. Then the supraspinatus and infraspinatus are repaired either by margin convergence or if there is still inadequate lateral mobility to these tendons, they are further mobilized with a posterior interval slide. They are then repaired in the standard manner to bone.There are two main traps in repairing massive tears that appear irreparable. The first of these is an unrecognized massive U-shaped tear, which can be repaired by margin convergence. If the tendon edges are mobile, then side-to-side sutures should be placed to see if it is repairable on margin convergence.The second trap is the rotator cuff that is scarred to the deltoid, the acromion and the coracoid. In such a case, one must actually excavate the cuff from the bone and soft tissue to which it has scarred. It is best to identify the fat pad posterior to the AC joint initially and then to remain in that fat layer, going laterally to develop a plane above the rotator cuff. It is helpful to skeletonize the spine of the scapula in doing this, in order to delineate the border between supraspinatus and infraspinatus.It is also important to debride the synovialized bursal leaders that are frequently present in chronic rotator cuff tears. Such bursal leaders connect the tendon margin to the deltoid fascia and can be confused for a tendon. However, this is not tendon. One must remember that the bursal leader inserts in the deltoid fascia whereas tendon inserts in the bone. These bursal leaders must be appropriately debrided. Once the tendon margins are properly identified, then the appropriate repair can be done using the principles outlined above.
There are some occasional irreparable cuff tears. In such cases, one can almost always do at least a partial repair and leave a defect in the area where the tear will not reach to the bone bed. However, using the techniques outlined in this article, the surgeon will find that irreparable tears are few and far between.
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[Figure – 1], [Figure – 2], [Figure – 3], [Figure – 4], [Figure – 5], [Figure – 6], [Figure – 7], [Figure – 8], [Figure – 9], [Figure – 10]