Christopher R. Adams and Stephen S. Burkhart
DEFINITION
A subscapularis tendon tear typically occurs at its insertion into the lesser tuberosity of the proximal humerus.
Although the subscapularis is the largest of the rotator cuff muscles, historically it has received little attention.
Subscapularis tendon tears are often overlooked and underdiagnosed; therefore, a proper evaluation of the shoulder is of paramount importance.
Treatment of subscapularis tendon tears can restore the functional stability of the shoulder.
ANATOMY
The subscapularis muscle originates from the medial two thirds of the anterior scapular fossa.4 The muscle courses laterally beneath the coracoid and becomes tendinous at the glenoid rim. The subscapularis tendon becomes confluent with the glenohumeral joint capsule deep to it and inserts into the lesser tuberosity of the proximal humerus (FIG 1).
The normal subscapularis tendon not only intermingles with the fibers of the glenohumeral joint capsule deep to it, but at its insertion it also intermingles with the fibers of the medial sling of the long head of the biceps tendon. The medial sling is composed of fibers from the superior glenohumeral ligament and the coracohumeral ligament complex.
The tendon insertion is about 2.5 cm long (range 1.5 to 3.0 cm) and is trapezoidal, with the widest portion at its most superior (cephalad) aspect.17
The superior aspect also happens to be the strongest part of the subscapularis insertion.8
FIG 1 • Subscapularis insertion. The subscapularis insertion is wider at its superior aspect and tapers at its most inferior aspect. The insertion resembles the shape of the state of Nevada.
The subscapularis muscle is innervated by the upper and lower subscapular nerves, and its blood supply is primarily derived from the subscapular artery.4
The main functions of the subscapularis muscle are to internally rotate and adduct the humerus and to provide an anterior restraint to humeral head translation. The subscapularis also acts in concert with the remaining rotator cuff muscles and deltoid to balance both the coronaland transverse-plane force couples of the glenohumeral joint.
This results in dynamic stabilization to centralize the humeral head on the glenoid (“maintain the golf ball on the golf tee”), providing a stable fulcrum for glenohumeral motion.
PATHOGENESIS
As with the other rotator cuff tendons, intrinsic factors may play a role in the development of a subscapularis tendon tear. Furthermore, extrinsic mechanical factors have also been implicated in the process.
The normal subcoracoid space (coracohumeral interval) represents the distance from the coracoid tip to the proximal humerus. If this space is stenotic, the coracoid tip will impinge against the insertion of the subscapularis, causing damage to the tendon insertion.
Anatomic and imaging studies have defined the normal coracohumeral interval to be between 8.4 mm and 11 mm.5,7,14
Subcoracoid stenosis is defined as less than 6 mm of space between the coracoid and the proximal humerus (either by magnetic resonance imaging [MRI] or arthroscopy).14
Patients with subscapularis tears often have a significantly reduced coracohumeral interval (5 mm with subscapularis tears vs. 10 mm without subscapularis tears).16
In subcoracoid impingement, the coracoid abuts against the anterior surface of the subscapularis, causing increased articular (under) surface tensile forces that can cause tendon fiber failure (FIG 2).
Two separate cadaveric studies found that subscapularis tendon tears are often partial-thickness articular tears. Furthermore, they usually begin at the superior aspect of the insertion and are common in the elderly population.18,19
However, complete tears of the subscapularis tendon often result in medial retraction of the tendon edge to the level of the glenoid.
The retracted tendon often pulls with it the adjacent medial sling of the biceps tendon (composed of fibers from the superior glenohumeral ligament and coracohumeral ligament).
The fibers of the medial sling are oriented approximately perpendicular to the fibers of the subscapularis tendon and arthroscopically appear as a comma-shaped soft tissue structure that we refer to as the “comma sign” (FIG 3).13
FIG 2 • Schematic drawing of the roller-wringer effect. In patients with subcoracoid impingement, the prominent coracoid tip indents the superficial surface of the subscapularis tendon. This creates tensile forces on the convex, articular surface of the subscapularis tendon and can lead to failure of the subscapularis fibers. C, coracoid; H, humerus. (From Burkhart SS, Lo IKY, Brady PC. A Cowboy's Guide to Advanced Shoulder Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2006.)
We have found the “comma sign” to be a useful guide for identifying the retracted superolateral edge of the subscapularis tendon.
The loss of the subscapularis tendon results in an unstable glenohumeral fulcrum and abnormal glenohumeral arthrokinematics.12
Chronic tears of the subscapularis should be repaired (even if there is fatty degeneration and significant muscle atrophy) because the subscapularis may have the capacity to function through a tenodesis effect.17
NATURAL HISTORY
There is little available information on the natural history of subscapularis tendon tears.
In some patients (especially those with massive rotator cuff tears) the tears can be disabling. Some patients with massive rotator cuff tears never regain functional overhead use of their arms without surgical intervention.
PATIENT HISTORY AND PHYSICAL FINDINGS
Although most subscapularis tears in the community are degenerative in nature, the classic scenario for a traumatic tear is forced external rotation.
Forced external rotation results in an eccentric tensile load, which can be particularly dangerous to a “tendon at risk.”
In contrast to patients with the typical posterosuperior rotator cuff tear, who have difficulty with overhead tasks, patients with subscapularis tears often have the burden of diminished function with tasks in front of the body and below the level of the shoulder.
The typical patient complains of chronic pain and loss of arm strength with activities of daily living in front of the body.
A complete physical examination is necessary, including evaluation of the cervical spine and both upper extremities. Examinations to perform are:
FIG 3 • A,B. Anterior structures from a posterior viewing portal of a right shoulder. The medial sling (M) of the biceps tendon (BT) inserts into the lesser tuberosity of the humerus (H) along with the superolateral margin of the subscapularis (SSc). C,D. Complete subscapularis tendon tear. In this situation, the comma sign (,) leads to the superolateral border of the subscapularis tendon. G, glenoid; C, coracoid. (From Burkhart SS, Lo IKY, Brady PC. A Cowboy's Guide to Advanced Shoulder Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2006.)
Lift-off test: The test is positive when the patient cannot actively hold the hand away from the lower back; it is positive only when at least 75% of the subscapularis tendon is torn.1 The test is also difficult to perform for some patients with restricted shoulder motion.
Napoleon test, also known as modified belly press: Wrist flexed 90 degrees and elbow posteriorly positioned indicates a positive test; the entire subscapularis tendon is torn. An intermediate test is indicated by wrist flexed 30 to 60 degrees; more than 50% of the subscapularis tendon is torn. A negative test occurs when the patient is able to “strike the pose”; less than 50% of the subscapularis tendon is torn.
With a significant subscapularis tendon tear the patient flexes the wrist, the elbow drops backward, and the posterior deltoid acts to pull the hand against the belly.
Bear hug test: A positive test is indicated when the physician can pull the patient's hand off the shoulder.1 This is the most sensitive test for an upper subscapularis injury (eg, a partial tear involving the superior aspect of the subscapularis tendon).1
A patient with a subscapularis tear often has diminished internal rotation strength and increased passive external rotation (compared to the opposite extremity).
A patient with a subscapularis tear may also have additional pathology in his or her shoulder.
This again emphasizes the importance of a good physical examination that also evaluates the other rotator cuff tendons, the biceps tendon, glenoid labrum, and so forth.
Patients with a posterosuperior rotator cuff tear often have pain, weakness, or limited elevation and external rotation.
A significant tear of the subscapularis tendon may result in disruption of the medial sling of the long head of the biceps tendon. This can lead to either partial or complete tears of the biceps tendon with or without medial subluxation.
A tear of the glenoid labrum often results in “catching” pain that occurs with certain positions of the shoulder, depending on the location of the tear.
IMAGING AND OTHER DIAGNOSTIC STUDIES
We routinely obtain five views of the shoulder: anteroposterior (AP) internal rotation, AP external rotation, AP with 30-degree caudal tilt, outlet view, and axillary plain films.
Evaluation of the plain films may reveal proximal humeral migration (especially with longstanding massive rotator cuff tears), acromial morphology, glenohumeral or acromioclavicular joint degenerative changes, anterior humeral translation (seen with subscapularis tendon disruptions on the axillary view), and so forth.
We also routinely obtain an MRI of the affected shoulder.
The MRI can provide important information on the location and extent of the subscapularis tendon tear.
It can also determine whether additional pathology in the shoulder coexists (eg, additional rotator cuff tears, medial subluxation or tears of the long head of the biceps tendon, ganglion cysts, labral tears).
Tears of the subscapularis tendon are best appreciated on the axillary images of the MRI (FIG 4).
FIG 4 • T2-weighted axial MRI showing a decreased coracohumeral space (yellow line) and complete tear of the subscapularis tendon. Yellow arrow indicates the edge of the retracted subscapularis tendon. (From Burkhart SS, Lo IKY, Brady PC. A Cowboy's Guide to Advanced Shoulder Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2006.)
Signal characteristics consistent with fluid may be seen with partial-thickness tears, whereas a loss of part or all of the normal tendon will be seen with full-thickness tears.
DIFFERENTIAL DIAGNOSIS
Subscapularis tendinitis or bursitis
Posterosuperior rotator cuff tear
Biceps tendinitis
Labral tear
Neurologic impairment
NONOPERATIVE MANAGEMENT
The role of nonoperative treatment in patients with symptomatic subscapularis tears is very limited.
Most patients who present to orthopedic surgeons with subscapularis tears have had the tear for a long time.3
Furthermore, most have attempted and failed nonoperative treatment.
However, for patients who are not good surgical candidates (eg, very old, ill), nonoperative treatment is warranted.
Nonoperative treatment typically consists of activities as tolerated with gentle stretching and progressive strengthening of the shoulder.
SURGICAL MANAGEMENT
Preoperative Planning
The history, physical examination, plain films, and MRI should all be reviewed before operative intervention.
Positioning
The anesthesiologist administers general anesthesia with endotracheal intubation and applies protective eyewear to the patient.
The patient is rotated into the lateral decubitus position and an axillary roll is placed.
The patient is well padded with pillows beneath and between the legs.
The patient is secured in place with a vacuum beanbag and is tilted back approximately 10 degrees.
A warming blanket is applied to prevent hypothermia.
The sterile field must extend posteriorly to a position medial to the scapula and anteriorly just lateral to the nipple.
After the patient is properly protected, positioned, padded, and draped, the surgeon performs an examination under anesthesia.
The assistant prepares the operative extremity with a sterile scrub.
The arm is then placed in 5 to 10 pounds of balanced suspension (Star Sleeve Traction System; Arthrex Inc., Naples, FL) with the shoulder in 20 to 30 degrees of abduction and 20 degrees of forward flexion (FIG 5).
Approach
Successful treatment of subscapularis tears has been documented with both open and arthroscopic techniques.
We prefer and will present our arthroscopic technique for treatment of a subscapularis tendon tear.
FIG 5 • Positioning in the lateral decubitus position. Photograph from the head looking downward showing the arm suspended in 20 to 30 degrees of abduction and 20 degrees of forward flexion.
TECHNIQUES
PORTALS AND VISUALIZATION
The surgeon should remember the “6 Ps” for arthroscopic portals: “Proper portal placement prevents poor performance.”
Our standard posterior viewing portal is placed 4 to 5 cm inferior (caudal) to the posterior border of the acromion and 3 to 4 cm medial to the posterolateral corner of the acromion (TECH FIG 1A).
A standard diagnostic arthroscopy of the entire glenohumeral joint is performed.
To fix the tear one must be able to see the tear. This point cannot be emphasized enough, and throughout the procedure special attention is paid to optimize visualization by controlling bleeding.
Key factors include minimizing the pressure differential between the patient's blood pressure and the arthroscopic pump pressure; making use of the Bernoulli principle to achieve turbulence control; and using electrocautery as needed to cauterize specific bleeding points.
The subscapularis tendon presents a unique problem to visualization. The tendon tear is often in a very confined space that may be unfamiliar to the surgeon (TECH FIG 1B). This space can become even more constricted with soft tissue swelling as the case proceeds, so we recommend repairing the subscapularis tendon before addressing any other problems in the shoulder.
We have found that examination of the subscapularis tendon for a partial tear is optimized with shoulder flexion and internal rotation (lifts the subscapularis tendon off its footprint on the lesser tuberosity; TECH FIG 1C).
Visualization is further enhanced with a “posterior lever push” in which an assistant pushes the proximal humerus posteriorly while pulling the distal humerus anteriorly (TECH FIG 1D).
A 70-degree arthroscope is an extremely helpful additional tool that can improve visualization by providing an “aerial view.”
The initial identification and orientation should be done with a 30-degree arthroscope, however, because it is easy to get lost and stray dangerously inferior into the vicinity of neurovascular structures if the 70-degree arthroscope is used initially.
The primary working portal is the anterosuperolateral portal, which is 1 to 2 cm lateral to the anterolateral corner of the acromion.
An 18-gauge spinal needle is introduced into the glenohumeral joint to make a 10-degree angle of approach to the lesser tuberosity.
Advantages of the anterosuperolateral portal include a good angle of approach to prepare the lesser tuberosity bone bed; a near-parallel angle of approach to the subscapularis for mobilization and antegrade suture passage; and an angle of approach to the coracoid tip that will allow a coracoplasty to be made in a plane that is parallel to the subscapularis tendon.
The next portal created is the anterior portal, which is 4 to 5 cm inferior to the anterior acromion, just lateral to the coracoid tip.
An 18-gauge spinal needle is introduced into the glenohumeral joint to determine a 45-degree angle of approach to the lesser tuberosity, and then the portal is established in that line of approach.
Advantages of the anterior portal include an optimal angle of approach for anchor placement, suture management, and on occasion retrograde suture passage (although we almost always do antegrade suture passage through the subscapularis tendon via an anterosuperolateral portal).
TECH FIG 1 • Portals and visualization. A. The anterior (1), anterosuperolateral (2), and posterior (3) portals for arthroscopic subscapularis tendon repair. B,C. Arthroscopic view of the subscapularis insertion of a right shoulder from the posterior portal using a 30-degree arthroscope with the arm in 30 degrees of abduction and neutral rotation (B) and in internal rotation (C). D. The posterior lever push. H, humeral head. (From Burkhart SS, Lo IKY, Brady PC. A Cowboy's Guide to Advanced Shoulder Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2006.)
BICEPS TENDON
Subscapularis tendon tears are often associated with tearing or medial subluxation of the long head of the biceps tendon.
The long head of the biceps tendon should be inspected from its base to the intertubercular groove. It is often helpful to pull the tendon into the glenohumeral joint and to pay particular attention to the medial surface of the tendon for partial tearing.
Also, internal and external rotation of the humerus may reveal subluxation of the tendon. The biceps tendon should never pass posterior to the plane of the subscapularis with rotation of the humerus.
Most of our patients with biceps tendon tearing or subluxation in association with a torn subscapularis receive a biceps tenodesis.
In our view the alternatives are suboptimal.
Biceps tendon subluxation left alone will result in increased stress to the subscapularis repair and may ultimately cause it to fail.
Significant biceps tendon degeneration may result in continued shoulder pain and dysfunction.
Biceps tenotomy has been shown in the literature to result in decreased elbow flexion and forearm supination strength, and some patients consider it aesthetically undesirable.15 Therefore, we perform a biceps tenotomy only in elderly patients with low demands and poorly defined arm musculature.
The initial step in the tenotomy is to place two half-racking stitches 1 to 2 cm distal to the base of the long head of the biceps tendon (TECH FIG 2). These sutures tighten and lock against the tendon to securely hold it after it is tenotomized (in preparation for tenodesis).
The tenotomy is made at the base of the biceps with electrocautery or scissors. Care is taken not to damage the superior labrum.
The biceps tendon is then extracted extracorporeally through the anterosuperolateral portal. Pushing on the skin around the tendon's exit point and flexing the elbow and shoulder aid in presenting the tendon out of the portal.
A no. 2 FiberWire (Arthrex) whipstitch is run with three or four passes on each side of the tendon.
TECH FIG 2 • Biceps tendon. Two half-racking sutures are placed to secure the biceps tendon before tenotomy. A. A Penetrator (Arthrex) hands off a FiberWire suture (Arthrex) to a suture retriever. B. The FiberWire loop is then exteriorized and the free ends of the suture are passed through the loop. C. The free ends of the suture are tensioned to bring the suture loop down to the tendon. D. The biceps tendon is released close to its insertion on the superior labrum using an electrocautery Bovie. E. The biceps tendon is pulled out through the anterosuperolateral portal using the two half-racking sutures and a locking whipstitch is placed in the biceps, four throws on each side of the tendon. BT, biceps tendon; G, glenoid. (From Burkhart SS, Lo IKY, Brady PC. A Cowboy's Guide to Advanced Shoulder Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2006.)
The whipstitch sutures are temporarily pulled through the anterosuperolateral portal outside the cannula so that it will be out of the way until it is time to do the biceps tenodesis.
This temporary tenotomy improves subscapularis visualization and working space. At the end of the case, after the subscapularis tendon has been repaired, we prefer to anchor the biceps tendon to bone using the BioTenodesis screw system (Arthrex) to obtain a secure interference fit of tendon against bone.
SUBCORACOID SPACE
The first step in defining the subcoracoid space is to identify the coracoid tip.
If the subscapularis tendon is intact or partially torn, the coracoid tip is located just anterior to the upper border of the subscapularis tendon. With internal and external rotation of the humerus the coracoid tip can be seen as a moving bulge in the rotator interval.
Through the anterosuperolateral portal the electrocautery can be used to create a window in the rotator interval tissue to expose the coracoid tip (the surgeon must take care to preserve the medial sling of the biceps tendon).
If the subscapularis tendon is completely torn and retracted, the coracoacromial ligament is a useful guide to the coracoid tip.
The surgeon should use an instrument to palpate and confirm the location of the coracoid tip.
We have found that the best method of measuring the coracohumeral interval is direct visualization during arthroscopy with an instrument of known size through the anterosuperolateral portal (eg, the diameter of a shaver blade). Gentle axial distraction may be necessary to obtain an accurate measurement if there is any proximal humeral migration.
We also routinely place the shoulder in the provocative position of flexion, horizontal adduction, and internal rotation to arthroscopically evaluate if there is any impingement between the coracoid tip and the subscapularis tendon and proximal humerus.
If there is any evidence of subcoracoid stenosis (coracohumeral interval less than 6 mm) or impingement, we perform a coracoplasty with a goal of creating a coracohumeral interval of 8 to 10 mm.
TECH FIG 3 • The subcoracoid space. A. A shaver is introduced through an anterolateral portal. The coracohumeral distance is measured (↔), and there is minimal space for the subscapularis tendon, signifying coracohumeral stenosis. B. A shaver placed through the anterosuperolateral portal has an approach angle that is essentially parallel to the subscapularis tendon. C,D. Arthroscopic pictures of a right shoulder with a posterior viewing portal, 70-degree arthroscope, and no lever push (C); with a posterior lever push (D). H, humerus; SSc, subscapularis tendon; C, coracoid; (,), comma tissue; LT, lesser tuberosity. (From Burkhart SS, Lo IKY, Brady PC. A Cowboy's Guide to Advanced Shoulder Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2006.)
The soft tissues on the posterolateral surface of the coracoid are removed (“skeletonizing” the coracoid) with electrocautery and a motorized shaver (the surgeon must be careful not to release the conjoint tendon from the undersurface of the coracoid tip; TECH FIG 3A,B).
The fibers of the coracoacromial ligament may be released for improved visualization.
The anterosuperolateral portal provides a great angle of approach for the high-speed burr to be parallel to the subscapularis tendon for the coracoplasty.
A “posterior lever push” may improve the anterior working space by 5 to 10 mm (TECH FIG 3C,D). A second assistant who is anterior to the patient in a lateral decubitus position provides a posterior force to the proximal humerus with a simultaneous anterior force to the distal humerus.
Alternating between the 30and 70-degree arthroscopes as needed optimizes visualization.
The coracoplasty improves the anterior working space for the subscapularis repair and prevents future abrasion to protect the repair.
SUBSCAPULARIS MOBILIZATION
We routinely perform a three-sided release for complete, retracted subscapularis tendon tears.
The three-sided release can be difficult secondary to retraction, scarring, and working in a constricted space.
The surgeon may be concerned about the proximity of neurovascular structures; however, a cadaveric study found that the axillary nerve, axillary artery, musculocutaneous nerve, and lateral cord of the brachial plexus are all more than 25 mm from the coracoid base.10
The key is to stay on the posterolateral aspect of the coracoid.
The first step to mobilizing the subscapularis is to place a traction suture at the junction of the superolateral tendon and “comma tissue” (TECH FIG 4A).
The comma tissue is a comma-shaped fibrous band of tissue at the superolateral border of the subscapularis tendon; its fibers are oriented at right angles to those of the subscapularis. It is the remnant of the medial sling of the biceps after it pulls loose from its footprint on the lesser tuberosity directly adjacent to the footprint of the upper subscapularis.
This can be done through the anterosuperolateral portal with a Viper or Scorpion suture passer (Arthrex) loaded with a free no. 2 FiberWire suture (Arthrex). The traction suture can then be held outside the cannula to allow continued use of the anterosuperolateral portal.
The anterior release (subscapularis from the posterolateral coracoid and deltoid fascia) may be done by alternating the electrocautery with the shaver.
If a coracoplasty was not performed earlier, the soft tissues are removed from the coracoid (“skeletonizing” the posterolateral coracoid; TECH FIG 4B).
The release is continued medial along the posterolateral coracoid until the subscapularis muscle belly is visible beneath the arch of the coracoid neck and base.
TECH FIG 4 • Subscapularis mobilization. A. A traction suture is placed at the junction of the comma (,) and the subscapularis tendon (SSc) in a right shoulder seen through a posterior viewing portal. B. The coracoid dissection (solid line) has skeletonized the posterolateral coracoid to the level of the coracoid neck (CN) during the anterior release. C. A 30-degree arthroscopic elevator, introduced through an anterosuperolateral portal, is used to perform the superior release, lysing adhesions between the subscapularis and the coracoid neck and base. D.A 15-degree arthroscopic elevator is used to develop the plane between the posterior aspect of the subscapularis tendon (SSc) and the anterior glenoid neck and glenoid labrum (GL) during the posterior release. H, humerus. (From Burkhart SS, Lo IKY, Brady PC. A Cowboy's Guide to Advanced Shoulder Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2006.)
The superior release (subscapularis from the undersurface of the coracoid neck and base) may then be done with a 30-degree arthroscopic elevator (TECH FIG 4C).
The release is done only to the midpoint of the undersurface of the coracoid neck (to prevent damage to the neurovascular structures medial to the coracoid neck).
The posterior release (subscapularis from the glenoid neck) may then be done with a 15-degree arthroscopic elevator (TECH FIG 4D). The release is continued medial until the subscapularis is freely mobile.
The posterior release is the safest release (because it is in a very safe plane between the subscapularis and the anterior glenoid neck). The inferior release is the most dangerous and has not been necessary in our experience.
BONE BED PREPARATION AND ANCHOR PLACEMENT
The anterosuperolateral portal has a great angle of approach for removing the soft tissues off the subscapularis footprint of the lesser tuberosity.
A ring curette may be used to precisely remove the soft tissues up to the articular margin. Then electrocautery is used to ablate any soft tissue on the footprint (TECH FIG 5A).
The high-speed burr then removes the “charcoal” (residual of electrocauterization) to a bleeding bone bed without decorticating the bone (TECH FIG 5B).
To decrease the tension at the repair site, we have found that the subscapularis footprint may be medialized up to 5 mm with no detriment to its function.
TECH FIG 5 • Bone bed preparation and anchor placement. A,B. An electrocautery probe is used to delineate a medialized footprint on the lesser tuberosity (A), and a power burr burrs off the “charcoal” down to bleeding bone (B). C. This skeleton shows how the arm is held in 20 to 30 degrees of abduction and 20 degrees of forward flexion during shoulder arthroscopy in the lateral decubitus position. D. Photograph from the head looking downward shows how the combination of abduction, forward flexion, and normal humeral retroversion necessitates a “hand on face” position during anchor insertion into the lesser tuberosity. This highlights the need for protective goggles on the patient. E. This “hand on face” position allows the surgeon to achieve an appropriate “deadman” angle to insert suture anchors into the lesser tuberosity. LT, lesser tuberosity; SSc, subscapularis. (From Burkhart SS, Lo IKY, Brady PC. A Cowboy's Guide to Advanced Shoulder Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2006.)
One anchor should be placed every centimeter, which typically results in one anchor for a partial tear and two anchors for a complete tear (if a single-row repair is done).
The anchors should be placed in order from inferior (caudal) to superior (cephalad).
We use double-loaded anchors to reduce the load on each suture.
The best angle of approach for anchor placement is typically through the anterior portal (TECH FIG 5C).
The surgeon's hand and instruments (eg, punch and anchor inserter) are often close to the patient's face, which is one reason we place protective eyewear on every patient (TECH FIG 5D,E).
SUTURE PASSAGE AND KNOT TYING
We prefer the Viper or Scorpion suture passers (Arthrex) because they allow antegrade suture passage and retrieval (retrograde suture passage is difficult because the coracoid often blocks a good angle of approach).
One strand of suture is retrieved from the anchor, pulled out the anterosuperolateral cannula, and loaded in the suture passer.
Tension is placed on the traction suture (which is inside the anterosuperolateral portal but outside its cannula) and the suture is passed about 10 mm from the lateral edge of the subscapularis tendon (TECH FIG 6A).
For the superior anchor, the sutures should be passed over the top of the superolateral border of the subscapularis, just medial to the “comma tissue.” This will provide a “ripstop” to prevent lateral cutout of the sutures.
The process is repeated for the second suture of the same anchor.
Both the sutures are tied through a clear cannula with a double-diameter knot pusher (Surgeon's Sixth Finger, Arthrex; TECH FIG 6B).
We use a six-throw arthroscopic surgeon's knot, which is composed of a static base knot of three stacked halfhitches followed by three reversing half-hitches on alternating posts (TECH FIG 6C).
The arthroscopic surgeon's knot with a doublediameter knot pusher has been found in the laboratory to have the best combination of loop and knot security.11
To maximize efficiency and visualization, we tie the sutures of the inferior anchor before working on the superior anchor (TECH FIG 6D).
After completing the subscapularis tendon repair we internally and externally rotate the humerus to be sure that we have achieved secure apposition of the tendon against the bone.
TECH FIG 6 • Suture passage and knot tying. A. During suture passage into the upper subscapularis tendon, the tendon is grasped and the suture passed at the junction of the subscapularis (SSc) and the comma (,). B. The double-diameter knot pusher allows the subscapularis tendon to be manipulated and held in the appropriate position while each halfhitch of the knot is tied. C. Drawing of base arthroscopic knot locked with three reversing half-hitches on alternating posts (RHAP). D. Sutures from the upper anchor have been placed at the junction of the vertically oriented comma tissue and the upper border of subscapularis tendon. H, humerus. (From Burkhart SS, Lo IKY, Brady PC. A Cowboy's Guide to Advanced Shoulder Arthroscopy. Philadelphia: Lippincott Williams & Wilkins, 2006.)
POSTOPERATIVE CARE
An arthroscopic subscapularis tendon repair is usually an outpatient procedure.
After the arthroscopic portals are closed, a sterile dressing is applied over the shoulder.
A sling with a small pillow is applied with the arm at the side. The sling is worn full-time for 6 weeks, except when bathing or eating.
During the first 6 weeks the patient should perform daily active wrist and elbow motion.
The patient must not externally rotate past neutral (straight-ahead position) for 6 weeks.
There is no overhead motion in the first 6 weeks.
At 6 weeks from the operation the sling is discontinued.
The patient is started on a passive stretching program that includes passive external rotation with a cane up to 45 degrees and overhead stretches with a rope and pulley.
At 12 weeks from the operation the patient is started on a strengthening program with elastic bands.
If the subscapularis tear is part of a massive anterosuperior rotator cuff tear, then strengthening is delayed until 16 weeks postoperatively.
Progression to light weights is based on the patient's progress.
Rehabilitation focuses on strengthening the scapular stabilizers and deltoid and rotator cuff muscles.
Return to full, unrestricted activities is usually at 6 to 12 months and is based on the patient, the size of the tear, the strength of the repair, and the patient's rehabilitation progress.
OUTCOMES
The results after arthroscopic subscapularis tendon repair have been quite favorable.2,3,9
The senior author (SSB)3 published his preliminary results in 2002.
In this series of 25 consecutive patients with a mean follow-up of 11 months, 92% had good or excellent results by the UCLA criteria.
There was a significant improvement in pain and functional motion.
Eight of ten patients who had proximal humeral migration preoperatively had reversal of the migration and functional overhead use of their arm.
Bennett2 also found encouraging results in his prospective cohort with 2to 4-year follow-up.
The patients had a mean American Shoulder and Elbow Surgeons (ASES) score improvement from 16 preoperatively to 74 postoperatively.
Visual analogue pain scores improved from 9 preoperatively to 2 postoperatively.
Kim et al,9 in a recent report of patients who had an arthroscopic repair of isolated partial articular-sided tears, found similar improvements in pain and function.
At a mean follow-up of 27 months, UCLA scores improved from 23 preoperatively to 33 postoperatively, ASES scores improved from 67 to 96, and visual analogue pain scores improved from 5 to 0.3.
COMPLICATIONS
Stiffness
Retear
Neuropraxia
Infection
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