7 Arthroscopic Subscapularis Repair
Abstract
Subscapularis repair has increased in popularity as its significant role in rotator cuff function has been better understood. This repair may be achieved either with open approach or arthroscopically. There are several techniques described to achieve adequate repair, but the underlying principle is to properly identify the tear and subsequently achieve secure fixation of the tendon back to its footprint. We present our technique for arthroscopic subscapularis repair. The described technique provides reduction of the retracted tendon, sufficient pullout strength, and compression of the tendon to the footprint to facilitate healing.
7.1 Goals of Procedure
Historically, most of the rotator cuff literature was devoted to the repair of the supraspinatus, infraspinatus, and teres minor tendons. 1 – 4 However, over the last decade, it has become clear that subscapularis tendon tears are more prevalent than previously reported, and play an important role in shoulder function. 5 – 7
The subscapularis is the largest and most powerful of the rotator cuff muscles and is more important for arm elevation than either the supraspinatus or infraspinatus. 8 It is the only anterior rotator cuff muscle, and as a result, repairs must be accomplished to balance the posterior forces of the rotator cuff. 9 The upper portion of the subscapularis is particularly important because this is the part of the insertion that is broadest superiorly, and this site serves as the anterior attachment of the rotator cable. 5 , 10 Finally, for tears extending into the supraspinatus, repair of the upper subscapularis decreases the stress on the adjacent repair of the supraspinatus. 11
Therefore, restoration of subscapularis function is essential for long-term maintenance of acceptable clinical results for both traumatic and nontraumatic rotator cuff tears. The goals of surgery are to restore the subscapularis back to its native anatomical footprint. As a result, its biomechanical function will be restored. The described technique provides reduction of the retracted tendon, sufficient pullout strength, and compression of the tendon to the footprint to facilitate healing.
7.2 Advantages
The arthroscope is minimally invasive and may allow a quicker recovery with less postoperative pain than an open approach. It also allows the surgeon to address other intra-articular pathology that may be encountered, including labral pathology and posterior superior rotator cuff tears. Potential disadvantages include the need for advanced arthroscopic skills, especially in patients with full thickness retracted subscapularis tendon tears.
7.3 Indications
A thorough history and physical examination should be performed to diagnose subscapularis tendon tears, as well as other concomitant pathology in the shoulder. Particularly useful tests include the lift-off test and bear-hug test. After correct diagnosis, subscapularis repair, whether open or arthroscopic, should be considered in any patient with functional limitations such as internal rotation weakness and pain who have not responded to conservative management. Repair of this tendon is integral to maintaining the dynamic stabilization of the shoulder through balancing of the force couple. In addition, other studies have highlighted that the integrity of the subscapularis tendon plays a key role in reducing the recurrences of rotator cuff tears. 12
The role of nonoperative treatment in patients with symptomatic subscapularis tears is limited. Oftentimes these injuries are unrecognized and patients with chronic tears can present with a long history of pain and dysfunction. 6 Furthermore, most patients will eventually fail nonoperative treatment modalities. In rare instances, when the patient is a poor surgical candidate, nonsurgical management is necessary. Nonoperative treatment modalities typically consist of activity modification with gentle stretching, progressive strengthening of the shoulder, and anti-inflammatory medications.
Subscapularis repair should also be considered in cases of medial subluxation of the long-head of biceps tendon, as the upper subscapularis contributes to the medial sling of the bicipital pulley.
7.4 Contraindications
Relative contraindications to surgery are lack of pain, severe atrophy, and retraction or significant fatty degeneration on MRI.
7.5 Preoperative Preparation/Positioning
The history, physical examination, and imaging (plain films and MRI) should be reviewed before the procedure. The preoperative imaging should be used to confirm the presence of a subscapularis tendon tear and the degree of fatty atrophy and retraction, and to identify pathology to the biceps tendon.
Axial sections of the shoulder should be scrutinized to evaluate disruption of the subscapularis tendon on the lesser tuberosity.
7.5.1 Anesthesia and Positioning
Arthroscopic subscapularis repair can be achieved successfully in the lateral decubitus or beach-chair position. Position is largely based on surgeon preference. The senior author prefers the beach-chair position due to the ease of mobility of the extremity and the option to convert to an open procedure if necessary. The patient is aligned on the edge of the table so that the affected shoulder and scapula are exposed. The back of the table is elevated so that the acromion is parallel to the floor. The head is secured to the operating table with a headrest device. Care is taken to prevent excessive neck flexion or extension.
The anesthesiologist administers regional anesthesia with intravenous sedation and applies protective eyewear to the patient. An articulating arm holder holds the extremity and allows for easy manipulation of the extremity ( Fig. 7.1 ).
7.6 Operative Technique (Table 7.1)
7.6.1 Portal Placement (Fig. 7.2)
Our standard posterior portal is approximately 2 cm inferior and 1 cm medial to the posterolateral edge of the acromion. However, we adjust the portal by small amounts as needed after feeling for the “soft spot.” An anterior portal is then established with an outside-in technique using a spinal needle. This portal is placed as to approach the lesser tuberosity at a 45-degree angle to facilitate anchor placement. A cannula is placed through this portal. A systematic diagnostic arthroscopy is performed looking for other intra-articular pathology, paying particular attention to the other rotator cuff and biceps tendons.
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After the diagnostic arthroscopy is complete, an anterosuperolateral (ASL) portal is established via an outside-in technique. This portal should be superior and lateral in the rotator interval, and serves as the predominant working portal during the procedure but may also be used for visualization during mobilization of the tendon. The spinal needle should enter just off the anterolateral edge of the acromion and be directed into the glenohumeral joint. Appropriate placement of this portal facilitates a parallel approach to the footprint and subscapularis tendon for mobilization and suture passage. We place an additional 8.25-mm cannula through the ASL portal.
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