Large to Massive Rotator Cuff Tears

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CHAPTER 21 Large to Massive Rotator Cuff Tears

Stephen Burkhart, Samuel Koo

PREOPERATIVE CONSIDERATIONS

During the past 10 to 15 years, there has been a dramatic evolution in the arthroscopic treatment of massive rotator cuff tears. In the past, many massive rotator cuff tears (more than 5 cm in greatest dimension, as defined by DeOrio and Cofield ¹) were regarded as irreparable. Today, we have gone from being unable to repair any rotator cuff tears arthroscopically to being able to repair almost all rotator cuff tears, even massive ones, arthroscopically.

Massive rotator cuff tears make up approximately 20% of all cuff tears ² and a considerably greater percentage (80%) of recurrent rotator cuff tears.³ In the early 1990s, the recommendation often included simple débridement of the massive tears.⁴ Although débridement of massive tears has been relatively successful in terms of pain relief, overhead function is often not an attainable goal, particularly for patients who do not have balanced force couples.⁵^,⁶

Advancement in arthroscopic shoulder surgery has now improved our understanding of tear patterns and has offered new opportunities and capabilities in terms of rotator cuff repair techniques.² Understanding tear patterns is particularly important. Without a comprehensive understanding of tear patterns, the traditional repair techniques have focused on covering the hole. This was usually accomplished via an open or miniopen approach and subsequent extensive release of the cuff muscles to achieve enough mobilization to allow a repair to the bone. This medial to lateral technique did not respect the true pattern of pathology. Also, the extensive mobilization required can result in overtensioning of the rotator cuff and its subsequent failure.⁷ This can lead to damage to the suprascapular nerve, thereby leaving a repaired cuff completely nonfunctional.⁸ This may explain the traditionally poor results repairing primary and recurrent massive rotator cuff tears via an open approach¹^,⁹^,¹⁰ or an arthroscopic approach based on a purely medial to lateral mobilization and repair.¹¹

More recently, some have proposed the use of orthobiologic tissue patches to cover the hole in massive rotator cuff tears.¹² Again, this approach does not respect the biomechanics of the rotator cuff and is therefore doomed to failure. Unless the rotator cuff tendons can be appropriately tensioned to achieve an optimal position along the muscle length-tension curve, ultimate improvement in function is unlikely.

Although truly irreparable rotator cuff tears do exist (tears with 75% or greater fatty infiltration),¹³ most patients with massive rotator cuff tears can obtain a good cuff closure and clinical result. The key to repairing the traditional irreparable tear is understanding the pattern of the tear and then knowing how to deal with each pattern. With a suitable knowledge of tear patterns and with adequate and appropriate mobilization and repair techniques (see later), most massive rotator cuff tears can and should be repaired. This leads not only to improved pain relief but also a return of a significant amount of function, usually including overhead function.²^,³

PRINCIPLES AND ANATOMY

Before we discuss rotator cuff repair, it would be instructive to review the principles and anatomy that guide our reconstructive strategies. Three key areas to understand are force couples, the rotator cable-crescent complex, and rotator cuff tear patterns.

Force Couples

A primary function of the rotator cuff is to balance the force couples about the glenohumeral joint. A force couple is a pair of forces that act on an object and cause it to rotate. For any object to be in equilibrium, the forces must create moments about a center of rotation that are equal in magnitude and opposite in direction. In the situation in which the center of rotation is equidistant from the point of application of each force, the forces must be equal and opposite in direction for equilibrium to exist.

In the shoulder, the coronal plane force couple has been described by Inman and colleagues.¹⁴ This force couple is a result of the balance of moments created by the deltoid versus those created by the intact portions of the inferior rotator cuff (Fig. 21-1). During abduction, the coronal plane force couple will only be balanced if the line of action of the rotator cuff force is below the center of rotation of the humeral head, so that it can oppose the moment created by the deltoid. Balancing the coronal plane force couple is essential because this maintains a stable fulcrum for glenohumeral joint motion.

FIGURE 21-1 Coronal plane force couple. The inferior rotator cuff must balance the moment created by the deltoid. a, moment arm of the inferior rotator cuff; A, moment arm of the deltoid; C, rotator cuff force; D, deltoid force; O, center of rotation.

An equally important force couple is the transverse plane force couple. This force couple consists of the subscapularis anteriorly, balanced against the posterior rotator cuff (Fig. 21-2). This force couple is relevant in massive rotator cuff tears in which the tear may extend more posteriorly, leaving only a remnant of intact posterior cuff. In many cases, the posterior rotator cuff is so weak that it cannot balance the anterior moment created by the large subscapularis tendon. Furthermore, a large posterior rotator cuff tear can result in such a deficiency that the moment created by the inferior rotator cuff is also insufficient to maintain equilibrium in the coronal plane. This can then result in anterior and superior translation of the humeral head and the inability to maintain a stable fulcrum of motion. Therefore, when faced with a rotator cuff tear, the primary goal of surgery is to balance the force couples in the transverse and coronal planes and not necessarily to cover the hole. Again, the goal of rotator cuff repair is not to bring a medialized tendon stump laterally to bone, but to restore the balance of forces that control shoulder motion.

FIGURE 21-2 Transverse plane force couple (axillary view). The anterior rotator cuff must balance the moment created by the posterior rotator cuff. I, infraspinatus; O, center of rotation; r, moment arm of the subscapularis; R, moment arm of the infraspinatus and teres minor; S, subscapularis.

Rotator Cable-Crescent Complex: Suspension Bridge Analogy

When arthroscopically viewed from the glenohumeral joint, the articular surface of the intact rotator cuff demonstrates an arching, cable-like thickening of the capsule surrounding a thinner crescent of tissue that inserts into the greater tuberosity of the humerus.¹⁵ This cable-like structure, which represents a thickening of the coracohumeral ligament, is consistently located at the avascular zone margin of the rotator cuff (Fig. 21-3). It extends from its anterior attachment into the greater tuberosity of the humerus, just posterior to the biceps tendon, to its posterior attachment near the inferior border of the infraspinatus. This rotator cable potentially serves a protective role by stress-shielding the thinner, avascular crescent tissue, analogous to a load-bearing suspension bridge.

FIGURE 21-3 The rotator cable and crescent. A, Superior view. B, Posterior view. The rotator cable spans the entire length of the supraspinatus and infraspinatus insertions. B, rotator crescent; BT, biceps tendon; C, rotator cable width; I, infraspinatus; S, supraspinatus; TM, teres minor.

Similar to the intact rotator cuff, a rotator cuff tear can also be modeled after a suspension bridge, in which the free margin of the tear corresponds to the cable and the anterior and posterior attachments of the tear correspond to the supports at each end of the cable’s span. This model would predict, and subsequent studies have shown, that despite a tear in the avascular zone of the supraspinatus tendon, the supraspinatus muscle could still exert a compressive effect on the glenohumeral joint by means of its distributed load along the span of the suspension bridge configuration. The study by Halder and associates ¹⁶ supports the concept that in small and medium-sized rotator cuff tears, the rotator cuff muscle forces are effectively transmitted along the rotator cuff cable, bypassing the torn supraspinatus tendon. That is why certain rotator cuff tears, even massive ones, can demonstrate functional kinematics and why after rotator cuff repair, good results can be achieved, even when a water-tight closure is not obtained.¹¹^,¹⁷

Furthermore, the implication of the cable-crescent concept contradicts the historic principle of covering the hole, particularly when using techniques such as tendon transfers to obtain closure of massive, so-called irreparable, rotator cuff tears. Others have advocated the use of tendon transfers, including the infraspinatus and subscapularis, to cover rotator cuff defects in massive tears.¹⁷ Transferring these muscles superiorly, however, significantly alters the normal mechanics of the rotator cuff.

Tear Patterns

The first step in approaching massive rotator cuff tears is recognizing the pattern of the tear. This point cannot be overemphasized. Arthroscopy has greatly enhanced our understanding of rotator cuff tear patterns. Unlike traditional open surgery, which is limited by an anterolateral exposure, arthroscopy is not restricted by spatial constraints. Using arthroscopic techniques, rotator cuff tears can now be assessed and treated from several different angles, with minimal disruption to the overlying deltoid. This new perspective on evaluating and treating rotator cuff tears has led to the recognition of four major types of rotator cuff tears: (1) crescent-shaped tears; (2) U-shaped tears; (3) L-shaped and reverse L-shaped tears; and (4) massive contracted, immobile tears.

Crescent-shaped tears are the simplest of all tears and, although they can be massive, these tears do not typically retract medially to a significant degree. They demonstrate excellent mobility from a medial to lateral direction and can be repaired directly to bone, with minimal tension to the anatomic bone bed (Fig. 21-4).

FIGURE 21-4 A, Crescent-shaped tear, superior view. B, These tears demonstrate excellent mediolateral mobility and can be repaired directly to bone. IS, infraspinatus; SS, supraspinatus.

In contrast, U-shaped rotator cuff tears extend much farther medially than crescent-shaped tears, with the apex of the tear adjacent to or medial to the glenoid rim. Recognizing this tear pattern is critical, because attempting to mobilize and repair the apex of the tear to a lateral bone bed will result in overtensioning of the rotator cuff margin and subsequent failure. These tears demonstrate significant mobility from an anterior to posterior direction and should be initially repaired in a side to side fashion using the biomechanical principle of margin convergence (Fig. 21-5).

FIGURE 21-5 A, U-shaped tear, superior view. B, These tears demonstrate excellent anteroposterior mobility and should be repaired with side to side margin convergence sutures first. C, They can then be repaired directly to bone. IS, infraspinatus; SS, supraspinatus.

L-shaped and reverse L-shaped tears are similar to U-shaped tears. These are usually massive tears, with a longitudinal component in the direction of the fibers of the rotator cuff and a transverse component along the lateral cuff insertion (Fig. 21-6). One of the leaves is more mobile than the other leaf and can be easily brought to the bone bed.

FIGURE 21-6 A, Chronic L-shaped tear, superior view B, These tears demonstrate excellent anteroposterior mobility. Margin convergence sutures should restore the anterolateral corner of the supraspinatus (A’) to its anatomic insertion point (A) first. C, It can then be repaired directly to bone in a tension-free manner. CHL, coracohumeral ligament; IS, infraspinatus; RI, rotator interval; SS, supraspinatus; Sub, subscapularis.

These first three tear patterns represent about 90% of posterosuperior rotator cuff tears and can be repaired using the principles outlined here. Thus, most rotator cuff tears, even massive tears, can be repaired without extensive mobilization with an understanding and recognition of these tear patterns. Repairing tears according to their tear pattern can lead to excellent results.²

In the fourth tear pattern, the massive, contracted, immobile rotator cuff tear, other techniques must be used.

HISTORY AND PHYSICAL EXAMINATION

As with all orthopedic conditions, a thorough assessment should begin with the history and physical examination. The chronicity of the tear is an important element of the history and is often difficult to ascertain fully. Although a history of a traumatic event, such as a fall onto an outstretched hand, is often reported as the initiating event, many patients with a massive rotator cuff tear will give a history of a long period of shoulder problems. These patients may have had a chronic rotator cuff tear that still allowed a balanced force couple across the glenohumeral joint. At the time of their recent trauma, they may extend their tears to the point where they lose overhead function. This is important to note in the history, because patients with a long period of shoulder symptoms are more likely to have rotator cuff tears that are large and require mobilization for repair.

The subscapularis examination is a key element to the shoulder examination that is frequently untested. The lift-off test is not positive until at least 75% of the subscapularis tendon is detached and therefore is not a good test for upper subscapularis tears.¹⁸ The bear hug test is the most sensitive test for a torn subscapularis, particularly a partial tear involving only the upper subscapularis.¹⁹ In this test, the patient places the hand of the affected side on the opposite shoulder with the fingers extended and the elbow elevated into a forward position. The examiner then tries to pull the patient’s hand off the shoulder perpendicular to the plane of the forearm as the patient resists (Fig. 21-7). If the examiner is able to lift the patient’s hand off the shoulder, this is a positive finding and is suggestive of at least a partially torn subscapularis tendon. Other tests for the subscapularis include the belly press and Napoleon tests.²⁰

FIGURE 21-7 The bear hug test. The extended hand of the affected shoulder is placed on the opposite shoulder as the patient resists the examiner’s force to pull the hand off the shoulder (arrow). The test is positive if the examiner is able to lift the hand off the shoulder.

DIAGNOSTIC IMAGING

Plain radiographs are important in initial assessment. The status of the glenohumeral joint must be determined because patients who suffer from moderate to severe glenohumeral degenerative joint disease (DJD) will be less likely to benefit significantly from arthroscopy and rotator cuff repair. In addition to arthritis, the surgeon should examine the plain films for evidence of superior migration of the humerus.

The next step in preoperative planning is to perform magnetic resonance imaging (MRI) of the shoulder. MRI can give the surgeon a good idea of the severity of the cuff tear and reveals associated pathologies. It is also helpful in surgical planning because the amount of fatty infiltration can be determined (see later).

INDICATIONS AND CONTRAINDICATIONS

Proper patient selection is important in any type of surgery. It is particularly vital in arthroscopic repair of massive rotator cuff tears. In the evaluation of a patient with a massive rotator cuff tear, the surgeon must weigh numerous factors in the decision-making process. First, and most important, are patient-related factors, such as the patient’s general health status and comorbidities. Also, the patient’s current and desired level of function are important. However, for most people with massive rotator cuff tears, surgery remains the best option to improve both pain and function.

Traditionally, fatty infiltration of more than 50% on preoperative MRI scans has been considered a poor prognostic indicator for rotator cuff repairs.²²^–²⁴ These patients have been discouraged from undergoing cuff repair with the assumption that surgical repair would not improve their outcome. In the senior author’s practice (SB), assessment of fatty infiltration within the muscle belly of the infraspinatus is critical, because it affects outcome. Muscle imparts elasticity to the rotator cuff and, without adequate muscle tissue, it would be difficult, if not impossible, to repair the tendon to the greater tuberosity. Lo and Burkhart have reported the results of repair of massive immobile rotator cuff tears that required the interval slide technique.²¹ Their patients demonstrated significant improvements in pain, active forward elevation, active external rotation, strength, and function. More recently, Burkhart and coworkers¹³ have evaluated the outcomes of massive cuff repairs and correlated these outcomes to preoperative MRI findings. The data suggest that patients who have greater than 75% fatty infiltration have a guarded prognosis for significant improvement because only 40% of these patients demonstrated clinical improvement. This is essential to determine prior to surgery because these patients can then be informed of their less favorable prognosis. They may choose not to proceed with surgical intervention, given their limited probability of functional improvement. However, patients with 50% to 75% fatty infiltration actually improved significantly after rotator cuff repair. In fact, 100% (17/17) of patients with less than 75% fatty infiltration had significant clinical and functional improvement after rotator cuff repair. Thus, in contradistinction to Goutallier’s cutoff of 50%, we consider all patients with less than 75% fatty infiltration on MRI scans to be potential surgical candidates.¹³

One area in which massive contracted rotator cuff tears are frequently encountered is during revision rotator cuff repair. Many authors have reported the results of revision rotator cuff surgery done through an open approach.¹^,⁹^,¹⁰^,²² Overall, these studies have demonstrated that although frequently effective in terms of pain relief, functional improvements have been slight. Recently, Lo and colleagues³ have reported on the arthroscopic revision of failed rotator cuff tears and demonstrated significant functional improvement in 93% of these patients, with a mean increase in the UCLA score of 15.5.

Some authors have also suggested proximal migration as a poor prognostic sign for rotator cuff surgery.²³^,²⁴ Burkhart and associates¹⁸ have demonstrated results to the contrary. In their study of patients who had proximal migration of the humeral head associated with anterosuperior cuff tears (subscapularis plus supraspinatus ± infraspinatus), 80% of patients demonstrated lasting reversal of the superior humeral head migration and a return of overhead function after repair. Proximal migration of the humeral head is not a contraindication to rotator cuff repair. Instead, one could argue that patients with proximal migration of the humeral head have the most to gain from rotator cuff repair. It is important to note, however, in the senior author’s (SB) experience, that proximal migration of the humerus combined with radiographic findings of a rounded greater tuberosity and acetabularization of the acromion suggest a long-standing tear that may be irreparable. In these situations, arthroscopic surgery may have limited applications.

TREATMENT OPTIONS

Conservative Management

Nonoperative treatment for massive rotator cuff tears includes lifestyle changes, exercise programs, and steroid injections. These methods are preferred in dealing with older low-demand patients with massive rotator cuff tears before consideration of surgery. Because these patients are often disabled at the time of their initial office visit, the temptation is to rush into surgical management. This can be a mistake. These patients should initially undergo nonoperative treatment with an exercise program. If the primary complaint includes pain, a series of steroid injections may dramatically benefit the patient. The senior author (SB) prefers a series of 3 monthly injections to control the inflammation and then limit the injections to once yearly. After these nonoperative measures have been used, a decision regarding surgical management can be considered. The surgeon may accelerate the surgical timetable somewhat if the involved extremity is on the patients’ dominant arm, if the patient is extremely disabled by his or her condition, and if the patient is physiologically younger than his or her chronologic age.

Arthroscopic Technique

The surgeon should begin every shoulder surgery with an examination under anesthesia. In the case of massive rotator cuff tears, one should pay particular attention to the amount of passive external rotation of the affected shoulder. If the patient demonstrates an increased arc of passive external rotation in the operative shoulder, this may be suggestive of a complete or near-complete tear of the subscapularis tendon.

After induction of general anesthesia, the patient is placed in the lateral decubitus position. Five to 10 pounds of balanced suspension is used with the arm in 20 to 30 degrees of abduction and 20 degrees of forward flexion. Diagnostic glenohumeral arthroscopy is then performed. One should consider placing the posterior portal more inferiorly than what is often used because significant fluid extravasation can be expected. As the shoulder swells, if the posterior portal is too high, the posterior acromion can prevent a direct parallel approach into the subacromial space.

The arthroscopic examination should begin with the anterior structures. A 30-degree arthroscope is used and the biceps tendon, anterior labrum, glenohumeral ligaments, and subscapularis tendons are examined. Particular attention must be paid to the insertion of the subscapularis tendon and the medial sling of the biceps. The junction of the medial sling with the superior border of the subscapularis tendon make up what has been called the comma sign (Fig. 21-8 ).²⁵

FIGURE 21-8 The comma sign. The comma is always located just lateral to the upper border of the subscapularis tendon (SSc). CT, coracoid tip; H, humerus.

At this point, the 70-degree arthroscope should be inserted to provide an aerial view of the subscapularis insertion as well as the medial sling of the biceps tendon. To visualize the subscapularis footprint better, the assistant can hold the arm in internal rotation and perform a posterior lever push.²⁶ The relationship between the anterior surface of the subscapularis and the biceps tendon is extremely important. At no time during rotation of the humerus should the biceps cut posterior to the plane of the subscapularis. If this occurs, it is suggestive of an incompetent medial sling of the biceps and early biceps tendon instability. This will require a biceps tenotomy or tenodesis.

The order of repair in dealing with massive cuff tears is important. If the surgeon identifies any operative biceps or subscapularis pathology, these problems must be addressed prior to any other procedures. This is because the anterior procedures become much more difficult when the shoulder becomes distended by fluid extravasation.

Next, it is important to determine the space available for the subscapularis. The phenomenon of the roller-wringer effect has been described, and subcoracoid impingement is important to diagnose and treat appropriately.²⁷ The best portal for approaching the subscapularis and coracoid is an anterosuperolateral portal, adjacent to the anterolateral corner of the acromion. The coracoid tip should be identified. If the subscapularis is not retracted, the tip of the coracoid should be at the level of the superior border of the subscapularis. The surgeon should make a window in the rotator interval to identify the coracoid tip and 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, an arthroscopic coracoplasty is necessary. The posterolateral aspect of the coracoid can be skeletonized with a combination of the shaver and electrocautery through the anterosuperolateral portal (Fig. 21-9). In exposing the coracoid, one must preserve the attachment of the conjoined tendon. The plane of the coracoplasty is parallel to the plane of the subscapularis tendon. The goal is to create a 7- to 8-mm space between the reconfigured coracoid tip and the anterior plane of the subscapularis tendon. The 30-degree arthroscope should be used initially to be sure that one does not get disoriented and wander inferior to the coracoid.

FIGURE 21-9 Posterior viewing portal of right shoulder (70-degree arthroscope). The coracoid neck (CN) and coracoid tip (CT) are visible. subscapularis tendon (SSc).

After appropriate treatment of any intra-articular pathology, the arthroscope is placed into the subacromial space through the same posterior skin incision. A lateral portal is created in line with the posterior aspect of the clavicle or slightly anterior or posterior, depending on the position of the rotator cuff tear.

To allow complete visualization and classification of the rotator cuff tear, all fibrofatty and bursal tissue must be removed from the margins of the tear. The tear is then identified and assessed for mobility. For tear pattern recognition, it is helpful to expose the scapular spine because it serves as a landmark to separate the supraspinatus tendon anteriorly and the infraspinatus located posteriorly (Fig. 21-10). Then, with the arthroscope posterior, the medial to lateral mobility of the tear can be assessed using a soft tissue grasper introduced through the lateral portal. Noncontracted crescent-shaped tears have excellent medial to lateral mobility and reduce easily to the bone bed. These tears are repaired directly to bone. Tears with poor medial to lateral mobility are then further assessed for anterior and posterior mobility, with the arthroscope in the lateral position. Posterior leaf mobility is assessed by pulling the leaf anteriorly with the grasper placed through the anterior portal; the anterior leaf is assessed by pulling the anterior leaf posteriorly with the grasper placed through the posterior portal. If the anterior and posterior leaves are mobile enough to allow side to side closure, then the tear is classified as a U-shaped massive tear and the technique of margin convergence is used. The converged rotator cuff margin is then repaired to bone as described here.

FIGURE 21-10 Lateral viewing portal of left shoulder. The scapular spine (SP) separates the infraspinatus (IS) from the supraspinatus (SS).

U-Shaped Tears

Repair of massive U-shaped tears can be gratifying, because many of these tears appear irreparable on first view. U-shaped tears demonstrate significant mobility from an anterior to posterior direction and should be initially repaired in a side to side fashion using the biomechanical principle of margin convergence (see later). One or two side to side sutures often will achieve such dramatic margin convergence that repair to bone can be simple (see Fig. 21-5). We typically begin side to side closure with a combination of the Penetrator and BirdBeak suture passers (Arthrex, Naples, Fla) that are used to pass sutures through the posterior and anterior leaves of the cuff tear, while using the arthroscope in a lateral subacromial position. Most of the large and massive tears require three to four side to side sutures. These sutures are tied sequentially, the most medial suture first, to achieve margin convergence of the cuff margin over the prepared bone bed. Two suture anchors are then placed, one for each leaf of the cuff tear. The anchor for the posterior leaf is placed approximately 1 cm anterolateral to the edge of the posterior leaf of the cuff so that the posterior leaf can be shifted proximally and anteriorly. This maneuver maximizes the moment produced by the posterior cuff in the transverse and coronal planes, thereby creating balanced force couples in both planes. The achievement of balanced force couples allows the shoulder to establish a stable fulcrum of glenohumeral motion. The anterior leaf typically is not as mobile as the posterior leaf in a U-shaped tear, and a significant shift of the anterior leaf usually is not possible or necessary, so the anterior anchor is placed adjacent to the edge of the anterior leaf. The sutures from the anchor are then passed through the tissue and tied. The free margin of the rotator cuff can then be easily repaired to the bone bed in a tension-free manner. The technique of margin convergence allows repair of seemingly irreparable tears and minimizes strain at the repair site.²⁸ Theoretically, this decreases the risk of rupture and subsequent failure of the rotator cuff repair.

L-Shaped Tears

In L-shaped and reverse L-shaped tears, one of the leaves is more mobile than the other leaf and can be easily brought to the bone bed and to the other leaf. In these cases, side to side suturing is first performed along the longitudinal split and then the converged margin is repaired to bone (see Fig. 21-6). In more chronic cases, the physiologic pull of the rotator muscle posteriorly will cause a reversed L-shaped tear to assume a more U-shaped configuration.

The bone bed must be meticulously prepared down to a bleeding base. Without this, good rotator cuff healing cannot occur. We use the electrocautery to remove the soft tissue from the tuberosity and then uses a high-speed burr to shave the bone to a bleeding base. A ring curette is used to prepare the articular margin.

Specific Techniques

A category of great interest is that of the immobile contracted rotator cuff tear. These are rotator cuff tears in which the tear margins will not reach the bone bed by standard repair and mobilization techniques. In the past, when such tears were encoun tered, only rudimentary mobilization techniques were available and frequently partial repairs were all that could be performed. With recent advances in arthroscopic shoulder surgery, we now have multiple tools in our arsenal to tackle these difficult tears. We will discuss some of them here.

Excavation of the Rotator Cuff.

In massive rotator cuff tears, the cuff is often scarred to the deltoid and the acromion. In such cases, one must excavate the cuff from the bone and soft tissue to which it has scarred. Identifying the fat pad posterior to the acromioclavicular (AC) joint and then developing the fatty layer between the rotator cuff below and the acromion above is the best way to achieve this goal (Fig. 21-11). One then proceeds laterally until the rotator cuff margin is found. In performing this dissection, we commonly view through a lateral portal and introduce our instruments through a posterior portal. By staying in the fatty layer, one can be sure to stay above any viable rotator cuff tissue. It is helpful to identify the spine of the scapula prior to doing this to delineate the border between the supraspinatus and infraspinatus. The skeletonized spine of the scapula looks much like the keel of a boat. The tissue anterior to the keel is the supraspinatus and the tissue posterior is the infraspinatus.

FIGURE 21-11 Lateral viewing portal of right shoulder. A, The fibrofatty layer is initially identified above the rotator cuff just posterior to the acromioclavicular joint. B, The layer is developed to identify the rotator cuff. Bursal tissues insert into the deltoid muscle fascia while the rotator cuff tendon inserts into the bone. AC, acromion; B, bursal leader; G, glenoid; H, humerus; RC, rotator cuff.

It is also important to débride the synovialized bursal leaders that are frequently present in chronic rotator cuff tears. Such bursal leaders connect the tendon margin to the deltoid fascia laterally and can be confused with tendon. A good way to distinguish tendon from bursa is to remember that the bursal leader inserts into the deltoid fascia but tendon inserts into the bone. These bursal leaders must be appropriately débrided. Once the tendon margins are properly identified, the appropriate repair can be performed.

Margin Convergence.

The term margin convergence refers to the phenomenon that occurs with side to side closure of large rotator cuff tears, in which the free margin of the tear converges toward the greater tuberosity as side to side repair progresses (see Fig. 21-5). This technique reduces the strain at the free edge of the cuff dramatically, leaving an almost tension-free converged cuff margin overlying the humeral bone bed for repair. For example, side to side closure of two thirds of a U-shaped tear will reduce the strain at the cuff margin to one sixth the strain that existed at the preconverged cuff margin. This mechanical strain reduction creates an added safety factor for the repair of tendon to bone because decreased strain means that there will be a lower likelihood of failure of fixation to bone. Strain reduction should also be effective in protecting against suture failure and propagation of the tear, even if the cuff margin is not repaired to bone. It is possible that the reduced strain can enhance function indirectly by decreased mechanical stimulation of pain receptors in the rotator cuff because deformation of these receptors should decrease as the strain decreases. Margin convergence is a powerful tool in the surgeon’s armamentarium for repairing massive rotator cuff tears.

Interval Slides.

Rarely, massive rotator cuff tears may be fixed and severely contracted, with poor mobility from a medial to lateral and anterior to posterior direction. This lack of mobility precludes either a repair directly to bone (as in crescent-shaped tears) or a repair after margin convergence (as in U-shaped or L-shaped tears). In these cases, an interval slide technique may be used to mobilize tendons.

In the orthopedic literature, the use of the open interval slide has been introduced. Cordasco and Bigliani ²⁹ have described the open anterior interval slide, whereas Codd and Flatow³⁰ have suggested an open posterior interval slide as well.

Tauro ³¹ was the first to describe an arthroscopic interval slide for release of the rotator interval from the supraspinatus tendon. An arthroscopic adaptation of the Bigliani technique was used to release the coracohumeral ligament and contracted immobile adhesed tears. This technique involved arthroscopic division of the rotator 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. This release improved the mobility of the supraspinatus, allowing repair of retracted tears.

Our procedure for the anterior interval slide is similar to the release of the subscapularis. The base of the coracoid is skeletonized and, in so doing, adhesions securing the anterior edge of the supraspinatus to the coracoid are released. The supraspinatus tendon is then identified and a traction stitch is placed at the anterolateral corner of the tendon and pulled out through a lateral portal. When performing an anterior interval slide, it is easiest to view from the lateral or posterior subacromial portal. These portals allow the correct orientation and visualization of the release. A dissecting scissor is introduced and the supraspinatus tendon is released from lateral to medial, starting at the free margin of the tendon tear and progressing to the base of the coracoid. This release also incises the coracohumeral ligament (Fig. 21-12). Alternatively, an anterior interval slide in continuity can be done by bluntly releasing the coracohumeral ligament from the coracoid base.³²

FIGURE 21-12 A, Massive, contracted, immobile tear, superior view. The anterior interval slide incises the interval between the supraspinatus (SS) tendon and rotator interval. B, The slide gives an additional 1 to 2 cm of lateral excursion. C, The residual defect is closed by side to side sutures between the infraspinatus and supraspinatus, and then the distal ends of these two tendons are repaired to bone. CHL, coracohumeral ligament; IS, infraspinatus; RI, rotator interval; SS, supraspinatus; Sub, subscapularis.

In general, with an isolated anterior interval slide, only 1 to 2 cm of lateral excursion of the supraspinatus is gained. With massive adhesed retracted tears, this is often not enough lateral excursion to allow apposition of the tendon to its bone bed. In this case, the addition of a second, more posteriorly located interval slide is necessary. When done in combination, the procedure is known as a double-interval slide.²¹

The posterior interval slide releases the interval between the supraspinatus and infraspinatus (Fig. 21-13). Arthroscopically exposing the scapular spine, which marks the interval between the supraspinatus and infraspinatus tendon, is imperative. This can be done by resecting the medial fibrofatty tissue until the arching column of the scapular spine is visible. Traction sutures are then placed on the supraspinatus and infraspinatus tendons. The posterior release is performed by cutting between the supraspinatus and infraspinatus tendons with an arthroscopic scissor, aiming toward the base of the scapular spine (Fig. 21-14).

FIGURE 21-13 A, Massive, contracted, immobile tear, superior view. The double-interval slide involves an anterior interval slide between the supraspinatus (SS) tendon and rotator interval and a posterior interval slide, between the SS and infraspinatus (IS). B, The anterior slide gives an additional 1 to 2 cm of lateral excursion and the posterior slide gives up to 3 to 5 cm of excursion. C, The tendons can then be repaired to the lateral bone bed. D, The residual defect between the tendons (SS and IS) is closed by side to side sutures. CHL, coracohumeral ligament; RI, rotator interval; Sub, subscapularis.

FIGURE 21-14 Posterior interval slide. While aiming toward the scapular spine, the arthroscopic scissors cut between the tendons of the infraspinatus and supraspinatus.

Care must be taken to protect the suprascapular nerve as it curves around the base of the scapular spine. To help protect the nerve, the supraspinatus and infraspinatus should be pulled laterally while the surgeon releases the interval. This pulls the tendon away from the nerve to decrease the chance of damage while cutting the interval. Also, the blades of the scissors should be raised above the level of the posterosuperior glenoid neck so as not to entrap the nerve at the base of the scapular spine in case one inadvertently slips medially with the scissors. This allows a safe release of the posterior interval. The release is terminated once the fat pad is reached.

By doing the double-interval slide, 3 to 5 cm of additional lateral excursion of the supraspinatus and infraspinatus can be attained. 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 floppy and difficult to control, we repair them to bone prior to placing side to side sutures.

Footprint Reconstruction.

The rotator cuff footprint is a complex three-dimensional structure overlying a large surface of the proximal humerus. One potential shortcoming of suture anchor repair of the rotator cuff is that suture anchors provide point fixation only. Therefore, when performing an arthroscopic rotator cuff repair with a single row of lateral anchors, the normal footprint of the rotator cuff is not restored and the medial aspect of the rotator cuff tendon insertion can lift away from the bone bed during abduction of the shoulder.

A double-row repair using a row of medial anchors at the articular margin and a row of lateral anchors restores the footprint of the rotator cuff more adequately and increases the area of contact for healing. Furthermore, by providing a second row of fixation, the number of points of fixation is increased, thereby increasing the strength of the initial repair construct and decreasing the load that each anchor must resist. All these factors can potentially improve the mechanical strength and function of the repaired rotator cuff by providing more complete healing across the anatomic footprint.³³ Cadaveric studies have highlighted the superiority of a double-row repair at restoring the supraspinatus footprint compared with a single-row repair.³⁷^–³⁹ In our experience, a single lateral row reconstituted 47% of the footprint in 26 patients whereas the double-row repair reconstituted the remaining 53% in these patients.³⁴

Today, in addition to the double-row, we now have a transosseous-equivalent or suture bridge technique in which compression is applied to the tendon against the prepared bone bed (Fig. 21-15). In this technique, two rows of fixation with sutures from the medial row draping over the tendon laterally provide increased tendon contact and compression over the anatomic footprint to improve and promote healing.³⁵^,³⁶ Using this technique, Frank and associates³⁷ have demonstrated a high healing rate on imaging studies at 1 year. Of the first 25 patients repaired with this technique, 88% had an intact rotator cuff repair on MRI evaluation. This indicates excellent cuff healing, as judged by the intact repair sites, compared with most standard arthroscopic rotator cuff repair series. Although this is a small sample size, continuing advancements in arthroscopic rotator cuff repair hold much promise for the future.

FIGURE 21-15 Subacromial view of a double-row footprint reconstruction technique.

Subscapularis Mobilization and Repair.

When there is a complete tear of the subscapularis with retraction, finding the retracted subscapularis tendon can be difficult. The key to finding the subscapularis and differentiating it from the conjoined tendon and the coracoacromial ligament is to locate the comma sign ²⁵ (see Fig. 21-8). The comma sign is a comma-shaped arc of tissue located at the superolateral border of the subscapularis, which always will lead the surgeon to the superolateral border of the subscapularis. The comma is actually the remnant of the medial sling of the biceps and is composed of fibers of the medial head of the coracohumeral ligament as well as a portion of the superior glenohumeral ligament. Typically, when the subscapularis fails completely, the medial sling of the biceps will pull away from the lesser tuberosity so that it remains confluent with the superolateral subscapularis tendon. This is convenient because the comma then allows the surgeon to be able to delineate the superolateral aspect of the subscapularis fully.

If the biceps is intact, visualization will be much easier if one does a biceps tenotomy (in preparation for later tenodesis) prior to repairing the subscapularis. We generally prefer to do a biceps tenodesis except in older patients who have low demands. In these patients, we perform a simple tenotomy.

Initially, two half- racking sutures are placed through the biceps tendon and the tendon is detached from the superior labrum with arthroscopic scissors (Fig. 21-16). The tendon is then exteriorized through the anterosuperolateral portal and a whipstitch is placed in the tendon (Fig. 21-17). The biceps tendon is allowed to retract down the bicipital groove prior to performing a tenodesis with a Biotenodesis interference screw (Arthrex) after the subscapularis repair. One must recognize that biceps tenotomy or tenodesis is important in the case of biceps subluxation or dislocation. If the biceps is not transferred out of the way of the subscapularis to a tenodesis site, the persistent force of the subluxed biceps over the top of the subscapularis repair will cause the repair to fail.