Arthroscopic Intramuscular Side-to-Side Repair of an Isolated Infraspinatus Tear

Given the relatively low overall incidence of intramuscular infraspinatus tears, the indications for arthroscopic side-to-side suture repair are not well described in the literature. For most patients, indications for surgery include persistent pain and/or weakness after failure of nonoperative treatment in the form of activity medication, physical therapy, and in some cases, injections. A 25-year-old right hand–dominant man presented with initial complaints of atraumatic right shoulder pain. He was managed nonoperatively with subacromial-space corticosteroid injections and physical therapy. Several months after his initial presentation, he was passing a basketball and felt acute anterior shoulder pain, which was exacerbated by overhead activities and became associated with pain at night while sleeping. The physical examination findings were remarkable for atrophy throughout the infraspinatus fossa as well as decreased strength in external rotation; the patient also had moderate tenderness in the bicipital groove. MRI showed a full-thickness tear of the infraspinatus muscle at the myotendinous junction with notable fatty infiltration within the muscle belly; the supraspinatus and subscapularis muscles and tendons were intact (Fig 1, Fig 2, Fig 3). In light of the patient's symptoms, examination findings, and imaging findings and the failure of nonoperative treatment strategies, we recommended an arthroscopic side-by-side rotator cuff repair.

We routinely administer both regional anesthesia through an interscalene block and general endotracheal anesthesia. We position the patient in the beach-chair position with the scapula stabilized with rolled towels between the scapula and the operating table. Preparation and draping are performed in sterile fashion, and intravenous antibiotics are given before incision.

We use a mechanical arm holder (Trimano; Arthrex, Naples, FL) to place the surgical arm in line with the body, with slight anterior traction. We use a standard posterior portal that is localized 2 cm inferior and 1 cm medial to the posterolateral corner of the acromion. By use of an outside-in-technique, a standard anterior midglenoid portal is established through the rotator interval just lateral to the coracoid process. Diagnostic arthroscopy and a careful evaluation of the rotator cuff are performed. Slight abduction with forward elevation can improve visualization of the undersurface of the rotator cuff. If the patient is noted preoperatively to have had positive physical examination findings and complaints consistent with long head of the biceps tendon pathology, the long head of the biceps tendon is released from its insertion on the superior glenoid for subsequent tenodesis. The remaining rotator cuff tissue, including the infraspinatus on its articular surface and the subscapularis, as well as the other intra-articular structures, including the labrum and the articular cartilage of the humeral head and glenoid, is carefully evaluated and managed appropriately.

After diagnostic arthroscopy, the arthroscope is inserted from the posterior portal into the subacromial space, and a lateral portal at the mid-acromial line, just posterior to the acromioclavicular joint, is established 2 to 3 cm lateral to the acromion by use of spinal needle localization. A thorough subacromial decompression, including elevation of the coracoacromial ligament off the anterior margin of the acromion, is performed. We then perform an acromioplasty using a posterior cutting-block technique. After adequate subacromial decompression, thorough evaluation of the bursal aspect of the rotator cuff is performed. In this case, there is a visible disruption of the myotendinous junction of the infraspinatus tendon (Fig 4). This disruption comes off of the tendon insertion as it wraps around the corner of the humerus and proceeds posteriorly toward the spine of the scapula (Video 1). We use sequential No. 2 FiberTape suture tapes (Arthrex), which are placed in a side-to-side fashion, beginning at the most anterior-lateral position, thereby bringing the tendon and muscle out to length (Fig 5, Fig 6, Fig 7, Fig 8). Viewing from the lateral portal, the surgeon introduces a reusable curved Spectrum suture passer (ConMed, Largo, FL) from the posterior portal to pierce through the 2 ends of the tendon tear; a No. 1 polydioxanone suture (PDS; Ethicon, Cincinnati, OH) is passed and retrieved anteriorly. A simple knot is tied on the PDS, and FiberTape is passed through the loop, which is then pulled tight to shuttle the tape through the tendon. This FiberTape is tied using standard arthroscopic knot-tying techniques with reverse posts and alternating half-hitch knots. Five suture tapes in total are used to create an anatomic reconstruction of the infraspinatus myotendinous junction (Figs 9 and 10). When indicated, this is followed by a mini-open subpectoral biceps tenodesis, performed through a 2-cm incision along the anterior-inferior aspect of the patient's axilla (Fig 11). The senior author's (A.A.R.) preferred technique for this procedure has been described previously.^,  The wounds are then closed by standard techniques, and the patient's arm is placed into a sling with an abduction pillow. Pearls and pitfalls of the technique can be found in Table 1, and advantages and disadvantages can be found in Table 2.

Our standard rotator cuff repair rehabilitation protocol is used for patients undergoing intramuscular side-to-side repair of an isolated infraspinatus tear. Patients are maintained in a sling with an abduction pillow for the first 6 weeks, with gentle pendulum exercises permitted immediately after surgery. Physical therapy is initiated in the first postoperative week, with passive range of motion for the first 6 weeks with a goal of 140° of forward elevation, 40° of external rotation with the elbow at the side, and up to 60° to 80° of abduction with the arm in neutral rotation. Once use of the sling is discontinued at 6 weeks, patients are allowed to begin active-assisted and active range of motion including periscapular muscle strengthening. At 8 weeks, light resistive training is allowed with the elbow at the side. Gentle strengthening is allowed at 12 months, with sport-specific rehabilitation exercises allowed at 4.5 months.