Anterosuperior Tears (Irreparable): Open Latissimus Dorsi Transfer

INDICATIONS

The latissimus dorsi muscle tendon transfer is indicated in younger, active patients with irreparable, anterosuperior (ie, subscapularis with or without supraspinatus) rotator cuff tears who present after failed nonoperative treatment with persistent pain and/or shoulder dysfunction consisting of internal rotation weakness, and static or dynamic humeral subluxation.

PREOPERATIVE PREPARATION

History

Comprehensive history-taking is essential to gather important information about the patient’s condition, and determine whether a latissimus dorsi muscle tendon transfer is appropriate. Most patients present with shoulder pain combined with reduced motion and internal rotation weakness. Moreover, patients might report history of recurrent anterior dislocations or subluxations. One must also understand the acuity or chronicity of symptoms and their progression over time. It is crucial to inquire about the type and number of prior surgical interventions especially on the affected shoulder, which plays an important role in decision making. The medical history and active medications should be sought including any relevant conditions that can affect the tendon transfer healing process such as diabetes mellitus, autoimmune disorders, ischemic heart diseases, corticosteroid intake, and biologic medications. Other important parameters are the patient’s hand dominance, occupation, activity level, and how the patient’s quality of life have been affected. One must also evaluate the patient’s social history such as social support system, their ability to comply with postoperative immobilization, and smoking habits.

Physical Examination

As with any shoulder condition, a full comprehensive shoulder examination should entail inspection, palpation to areas of pain, range of motion, and strength testing. With inspection, the affected shoulder should be scrutinized for any deformities, swelling, or muscle wasting, and must be compared
to the contralateral shoulder. Patients with irreparable subscapularis tears often present with anterior humeral head subluxation or anterosuperior humeral head escape. In terms of palpation, patients with subscapularis pathology often present with anterior tenderness over the lesser and the greater tuberosities if a concomitant supraspinatus tear is present. Range of motion examination can reveal increased passive external rotation of the affected shoulder indicating a compromised subscapularis. Active range of motion often reveals decreased internal rotation up the back and when the arm is abducted at 90°. Patients may also present with shoulder pseudoparalysis or pseudoparesis as the force couples about the glenohumeral joint are disrupted, resulting in reduced forward elevation secondary to anterior humeral subluxation (anterosuperior escape).

A multitude of special tests can be conducted to ascertain the presence of a subscapularis tear. The belly-press test entails asking the patient press on the abdomen with the palm of the hand while the arm is in internal rotation. Failure to maintain internal rotation indicated by the elbow dropping backward indicates a positive test. The angle of the wrist indicates the severity of internal rotation weakness, with an angle of 90° indicating a positive test. The bear hug test involves placing the palm of the hand of the affected side adjacent to the opposite shoulder. The patient is then asked to resist the examiner from pulling the arm upward. The lift-off test involves asking the patient to place the dorsum of the hand on the affected side on the back. The test is positive if the patient is unable to lift the hand away from the body. The subscapularis-specific tests have been reported with low sensitivity but high specificity.¹ The belly-press test has a sensitivity of 28% to 50% with a specificity of 96% to 99%. The bear hug test has a sensitivity and specificity of 19% to 60% and 81% to 92%, respectively, whereas the lift-off test has a sensitivity of 12% to 25% and a specificity of 95% to 100%. Each physical examination maneuver also identifies and preferentially tests various parts of the subscapularis, with the bear hug and belly-press predominantly testing the upper, tendinous portion of the subscapularis whereas the lift-off/Gerber test more effectively tests the lower, muscular portion. Combining physical examination maneuvers provides the greatest likelihood ratios.

Long head of biceps tendon pathologies are extremely common with subscapularis tears as the tendon subluxes from its groove. Physical examination of biceps yield provocative signs that are often positive such as a Popeye sign on inspection, tenderness on palpation of the bicipital groove, Speed test, and Yergason sign. Speed test is positive pain when the patient attempts elevation of the affected arm with the forearm supinated, and elbow extended against resistance. Yergason sign is positive when pain is elicited when the forearm is pronated with the 90° elbow flexion, and the patient attempts to supinate the forearm.

Diagnostics

Plain shoulders’ radiographs are useful to exclude glenohumeral osteoarthritis and advanced rotator cuff arthropathy adaptations (Hamada grade ≥ 3), both of which are contraindications for performing a muscle tendon transfer. Radiographs might often be normal with subscapularis tears; however, anterosuperior cuff deficiency can present with anterior humeral head subluxation, which is best appreciated on an axillary view. Additionally, radiographs are helpful in the evaluation of bony deformity and preexisting hardware.

Magnetic resonance imaging (MRI) is the most used imaging modality for assessing rotator cuff tears and muscle quality. In anterosuperior cuff deficiency, patients will have obvious subscapularis retracted tears with advanced fatty degeneration of at least half of the subscapularis muscle bulk, with or without supraspinatus tendon tears that are repairable or not (Figure 24-1). The subscapularis may also present with a failure in continuity, seen by tendon length greater than 60 mm, indicating a tear probability of 98%.² In addition, patients with subscapularis pathology present with long head of biceps tendon pathologies that can range from tendinitis, subluxation, to complete rupture.

FIGURE 24-1 Sagittal (A) and axial (B) T2-weighted magnetic resonance images demonstrating fatty infiltration and deficiency of the subscapularis and supraspinatus.

Computed tomography (CT) scans are primarily used to evaluate bony deformity and the degree of arthritic changes. Soft-tissue quality such as rotator cuff muscle fatty infiltration can also be ascertained with CT scans. CT arthrography is another valuable modality that is comparable to MRI in determining the presence of cuff deficiency especially in the presence of prior hardware.

TECHNIQUE

Positioning and Approach

Our preferred position is a beach chair with pneumatic arm positioner. The affected arm and hemithorax are then prepped and draped in the usual sterile fashion and the patient received appropriate antibiotics intravenously preoperatively as prophylaxis against infection (Figure 24-2). A standard deltopectoral approach is utilized. The long head of the biceps is identified and tagged with a #2 nonabsorbable suture. To facilitate the exposure of the latissimus dorsi tendon, we typically release 1 cm of the proximal part of the pectoralis major insertion. The long head of biceps is then tenotomized and pulled inferiorly; as such, the bicipital groove would be entirely empty. Alternatively, the incision may be extended below the border of the pectoralis major insertion, and this can be elevated and the latissimus dorsi tendon released by working above and below the pectoralis major.

FIGURE 24-2 Patient positioned in the beach-chair position, and draped in preparation for a standard deltopectoral approach.

(Courtesy of Jon J. P. Warner, MD.)

Latissimus Dorsi Tendon Harvest

We then place a blunt Hohmann retractor laterally underneath the deltoid and retract the pectoralis major medially to visualize the latissimus dorsi tendon, which is medial to the bicipital groove. The average tendon width is 3.3 cm with a length of 7.3 cm. Because of this, it is important to define the entirety of the latissimus insertion to obtain a complete release without tearing the muscle and tendon (Figure 24-3). A Cobb elevator is used to remove soft-tissues over the latissimus dorsi. The upper border of the latissimus dorsi is then released with electrocautery and the upper edge of the tendon is held with a clamp, and the tendon is then released along the bicipital groove. One must be cognizant not to harvest the teres major tendon accidently, which inserts immediately deep to the latissimus. The teres major insertion is composed of more muscular tissue and has a significantly shorter tendon compared to the latissimus tendon. In our experience, the latissimus dorsi and teres major tendon can be conjoined in approximately one-third of cases.³ In such a scenario, the teres major must be separated with Metzenbaum scissors so that the latissimus dorsi tendon is only harvested. Transferring the conjoint latissimus and teres major tendon anteriorly can potentially compress the axillary nerve in the quadrilateral space.⁴ The harvested latissimus dorsi tendon is prepared with nonabsorbable suture tapes on each side of the tendon (Figure 24-4). The radial nerve can be palpated and visualized medial to the latissimus dorsi tendon. With blunt dissection, the latissimus dorsi tendon can be mobilized to gain further excursion by releasing fascial bands to the triceps musculature. With the arm in a slightly flexed and internally rotated position, one would be able to bring the latissimus transfer proximally to either the supraspinatus or the subscapularis insertions. Biomechanically, placing the latissimus dorsi on the native subscapularis footprint provides the greatest internal rotation moment arm.⁵