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Pectoralis major tear repair, fixation help restore anatomy, biomechanics
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The pectoralis major muscle originates from multiple locations, including the costal cartilage of ribs two through six, the sternum, the medial half of the clavicle and the external oblique fascia. From this point of origin, the pectoralis major muscle divides into two muscular heads: the sternal and clavicular heads. These two muscular heads converge into a singular attachment at the humeral shaft; more specifically, at the crest of the greater tubercle and lateral lip of the intertubercular, or bicipital, groove. Nevertheless, uncertainty persists regarding the exact direction and rotation of the muscle fibers, as well as the number of tendons associated with these two muscular heads.
The pectoralis major muscle is responsible for adduction, internal rotation and forward flexion of the shoulder. As a result, an injury of the pectoralis major muscle jeopardizes the mechanics of the shoulder and, ultimately, an individual’s ability to perform activities of daily living. Although rare, a complete tear of the muscle has been reported and typically involves a forceful contraction during activities, such as bench press exercise. In most of these cases, the lesion is partial and may be successfully treated through conservative management, especially in older, less active patients. However, surgical repair allows for better restoration of the anatomy and biomechanics in the setting of a complete avulsion. Moreover, surgical repair is especially warranted in younger, more active patients given that a pectoralis major muscle tear, even if only partial, can be especially limiting and prevent full shoulder range of motion and strength.
Surgical technique
The patient is placed supine on the operating table. In many cases, a palpable defect at the pectoralis major tendon insertion can be identified. The coracoid process is first marked prior to the initial incision (Figure 1). Following this, the surgeon makes a 5-cm to 8-cm incision slightly medial to the axillary crease, beginning 3 cm distal from the coracoid process. The clavipectoral fascia is then excised in line with the skin incision, and both pectoralis major tendon heads are identified. In most cases, the clavicular head will be intact. Based on the clavicular head, the retracted sternal portion of the pectoralis major muscle may be identified, especially in a chronic case. Once identified, the pectoralis major muscle must be released from all adhesions to accommodate the sufficient mobilization needed for an anatomic reapproximation of the muscle.
Once the pectoralis major muscle is fully mobilized, the surgeon’s attention is then turned to the tendon insertion site on the humeral shaft. The long head of the biceps muscle must be identified and protected because it is in close proximity to the insertion site of the pectoralis major muscle (Figure 2). Then, using a combination of a coagulator and an acorn tip burr, the surgeon rids the insertion site of the muscle of all its soft tissue adhesions (Figure 3). This is done until a bleeding, bony bed surface is achieved. This surface will allow for optimal healing and fixation of the pectoralis major muscle following the repair. Following this, the surgeon uses a 3.7-mm spade tip drill to make three equidistant unicortical holes at the tendon insertion site on the humeral shaft. These three holes will be used for fixation via three Pec Buttons (Arthrex) or fixation posts at the level of tendon insertion, perpendicularly to the long axis of the humerus. Once the holes have been made, the surgeon passes #5 FiberWire (Arthrex) and FiberTape (Arthrex) suture through the tendon stump and posterior fascia so that the multiple limbs that emanate from the tendon can be used for fixation (Figure 4). Next, the surgeon loads three 3.2-mm x 11-mm Pec Buttons with the suture limbs and inserts them into the three previously drilled holes along the humeral shaft. Although the number of suture limbs is based on tear size and degree of retraction, we recommend the use of three #5 FiberWire or braided composite sutures and three FiberTape or high-strength sutures for a total of twelve suture limbs. For loading of the fixation posts, the surgeon should use two #5 braided composite and two high-strength tape suture limbs loaded into each fixation post. This translates into four suture limbs per fixation post for an even distribution of number and type of suture limbs across the three buttons (Figure 5). Prior to reapproximation of the muscle, the patient’s arm should be slightly abducted and externally rotated, which we consider ideal for fixation. The most distal fixation post is first loaded and inserted, and then the locking mechanism takes effect by toggling the suture limbs (Figure 6). The fixation post is then flipped and the most distal portion of the tendon stump arrives at its anatomical position. This step is repeated two more times for the medial and the most proximal fixation posts to achieve complete reapproximation of the muscle (Figure 7).
During reapproximation of the muscle, the surgeon must ensure the biceps tendon is safely retracted to avoid entrapment beneath the pectoralis major tendon. Following reapproximation, a physical examination of the shoulder should be performed with external rotation, flexion and abduction movements to verify the strength of the fixation, and to establish a patient-specific postoperative rehabilitation protocol. Once optimal fixation is confirmed, the wound should be copiously irrigated with saline solution. Then, a combination of autologous-conditioned plasma and platelet-rich plasma (PRP) should be injected at the tendon insertion site on the humeral shaft to maximize the healing potential (Figure 8). Following this step, the clavipectoral fascia and skin layers are closed using absorbable suture. Immediately following the procedure, the patient’s arm is placed in a sling.
Pearls and pitfalls
During completion of this procedure, surgeons should consider several pearls and pitfalls for a successful postoperative outcome. First, the clavicular head of the pectoralis major tendon should be used to identify the retracted sternal head. This is particularly important in the case of a chronic injury, in which scar tissue and retraction significantly increases how difficult it is to identify the tendon. On the other hand, in the setting of an acute tear, hematoma formation provides key information on the insertion site of the tendon on the humeral shaft.
Secondly, to ensure an optimal fixation and reapproximation of the muscle, the tendon must be released from all soft-tissue adhesions. To do this successfully, the surgeon should use his or her finger to free the muscle from any scar tissue formed as a result of the injury. The three holes to be used for the fixation posts should be equidistant to establish a strong, evenly distributed repair. Once the tendon is ready for reapproximation, it is whipstitched with #5 braided composite and high-strength tape suture across the stump. This ensures there is a large surface area of contact for the repair, which maximizes the healing potential and eventual strength of the repair. Prior to reapproximation, we suggest the patient’s arm be positioned in slight abduction and external rotation to ensure optimal tensioning of the repair construct. Lastly, it is important to identify and protect the long biceps tendon throughout the procedure due to its close proximity to the insertion of the pectoralis major tendon.
This surgical technique is technically demanding and requires knowledge of the anatomy. However, we believe the use of fixation posts minimizes the risk of a neurovascular injury as us of the spade tip drill does not violate the posterior humeral cortex.
- References:
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- For more information:
- Matthew T. Provencher, MD, can be reached at The Steadman Clinic, 181 W. Meadow Dr., Suite 4000, Vail, CO 81657; email: mattprovencher@gmail.com.
- Márcio B. Ferrari, MD, can be reached at Steadman Philippon Research Institute, 181 W. Meadow Dr., Suite 4000, Vail, CO 81657; email: mferrari@sprivail.org.
- George Sánchez, BS, can be reached at Steadman Philippon Research Institute, 181 W. Meadow Dr., Suite 4000, Vail, CO 81657; email: gsanchez@sprivail.org.
Disclosures: Provencher reports he is a paid consultant for and receives IP royalties from Arthrex and is a paid consultant for Joint Restoration Foundation (Allosource). Ferrari and Sánchez report no relevant financial disclosures.