In the setting of acute subscapularis tears, primary repair allows for restoration of internal rotation strength. However, in the setting of chronic, retracted tears, repair may not be possible or advisable. In these cases, a tendon transfer—from the pectoralis major (PM) or latissimus dorsi—might be considered.1 This case report presents a unique injury pattern involving a chronic subscapularis tear and an acute ipsilateral PM tear, raising new and as of yet unexplored treatment considerations. This report will emphasize the treatment approach for repairable and irreparable subscapularis tears, alongside a concomitant PM tear. Furthermore, this report will provide insight to surgeons managing similar shoulder injuries while aiming to enhance the service member’s function and readiness.

Case Report

A 29-year-old active-duty resident physician with a 10-year history of right shoulder pain and weakness after a skiing accident before active service was scheduled to undergo repair versus tendon transfer of a chronic retracted subscapularis tear. The patient had been able to perform his duties and military physical fitness testing but noticed increasing disability after years of active-duty service.

Two weeks before the planned surgery, the patient sustained an ipsilateral PM tear of the sternocostal head while rock climbing (Figures 1 and 2). When the patient returned for evaluation after the new injury, the treatment plan was revisited. This included the primary treatment plan of subscapularis repair and PM repair as well as alternatives such as transfer of the torn PM if the subscapularis was irreparable or transfer of the latissimus dorsi for an irreparable subscapularis with primary repair of the PM. These treatment considerations were discussed along with the possibility of a permanent medical profile and/or a medical evaluation board after recovery given the uncertainty surrounding outcomes of this combined injury. It was also communicated that the likelihood of either a permanent profile or a medical evaluation board was dependent on the reparability of the subscapularis and in turn the need for a tendon transfer, given the notable expected decrement in strength to the donor muscle and the modest gains in strength to the recipient. After a thorough discussion of the treatment options and potential outcomes, the patient elected to proceed with surgery, ultimately undergoing primary repair of both injuries, obviating the need for any tendon transfer.

Figure 1:

Right shoulder MRI with (A) axial T2 and (B) sagittal T1 demonstrating the subscapularis tear and atrophy (dotted line), respectively. A = acromion, G = glenoid, H = humerus, S = scapula, D = deltoid; SSc = subscapularis, Is = infraspinatus, SS = supraspinatus, Tm = teres minor.

Figure 2:

Images of the patient demonstrating asymmetric right axillary fold at (A) relative neutral abduction and (B) 90 degree abduction.

The patient was placed in the beach-chair position, and diagnostic arthroscopy was performed, confirming subscapularis tear retracted to the level of the glenoid. A biceps tenotomy and 3-sided arthroscopic release of the subscapularis were performed before moving to the open portion of the case. Through a deltopectoral approach, the intact clavicular head of the PM was identified. The torn sternocostal head was subsequently identified, mobilized, and Krackow-sutured. Next, the biceps tendon was delivered through the bicipital groove. The subscapularis was again identified and mobilized with the assistance of traction sutures. After mobilization, the tendon was able to be opposed to the lesser tuberosity without undue tension; thus, the decision was made to proceed with primary repair. The subscapularis footprint was prepared, and a linked double-row repair was performed with incorporation of the previously placed traction sutures (Figure 3). Afterward, the pectoralis footprint was prepared, and the sternal head was routed deep to the clavicular head for an anatomic repair. Repair was performed using two metal cortical buttons.

Figure 3:

Images of the right shoulder in the beach chair position. (A) Traction suture in sternocostal head (SH) of pectoralis major with the intact inferior portion of SH held by a clamp. B, Completed repair of the subscapularis (SS) long head of biceps tenodesis (LHBT). C, Repaired SH routed underneath the clavicular head (CH). D, Retraction of CH laterally to demonstrate repaired SH.

Finally, a biceps tenodesis was performed with a knotless, double-loaded, all-suture button. The wounds were thoroughly irrigated and closed. The patient underwent extensive physical therapy and is now over 3 years out from surgery. His strength and range of motion have returned to preinjury levels with the patient able to continue to rock-climb without apprehension or limitation—an activity that places considerable strain on both the pectoralis and the subscapularis. Most importantly, the patient has returned to full active-duty status and continues to serve as a military physician.

Discussion

Our case demonstrates a unique shoulder injury in terms of pathology and treatment considerations, with no previously published series reporting the incidence of the described injury pattern, nor case reports highlighting the complex treatment decisions such as transferring an already torn PM for an irreparable subscapularis.

Although subscapularis injuries are rarely seen in isolation, when they are accompanied by other injuries, it is usually biceps tendon pathology and/or other rotator cuff muscles, rather than PM rupture. However, our case is not entirely unprecedented because there have been other reports of service members with unusual, combined shoulder injuries. Wolfley et al and Arciero and Cruser reported on separate cases of HAGL lesions and PM tears.2,3 In their case reports, active-duty men presented after shoulder dislocations while bench-pressing, which eliciting several interesting parallels between their cases and ours.

Effective management of these complex injury patterns requires an understanding of the mechanisms behind the injuries, the function of the individual components involved and their possible compensatory roles. First, although this patient was not overtly unstable, his case and the aforementioned cases are mechanistically rooted in shoulder instability. This becomes apparent once we understand the roles that each injured structure plays within the shoulder. The anterior labrum and glenohumeral ligament serve as static stabilizers of the glenohumeral joint, preventing instability. While the subscapularis is most often singularly linked to its function as an internal rotator, it also serves an important role as a dynamic stabilizer of the shoulder.4 By contrast, the PM works in opposition to these structures, promoting anterior instability.5 While it might then appear that these injuries occur by dissimilar means, the commonality is that each tends to occur with the arm in vulnerable functional positions under maximal loads. This includes an outwardly rotated, extended, or flexed position which can injure the stabilizers while specifically for PM, this often includes an eccentric contraction.6

Given our patient's chronic and retracted subscapularis tear, tendon transfers were discussed as a possibility at his initial preoperative appointment, before his PM injury. Although several authors have reported success with transfers for irreparable subscapularis tears, these are very much salvage operations.1 Long-term outcomes for PM tendon transfer specifically demonstrated modest final outcomes of a subjective shoulder value of 71%, from 22% preoperatively, with 4% of patients requiring conversion to reverse total shoulder arthroplasty at 20-year follow-up.7 However, a comparison with our patient is difficult, given the older study population (eg, mean age 53.0 years), with far fewer physical demands than that of our patient.7 In addition, salvage procedures such as pectoralis tendon transfers demonstrate loss of internal rotation compared with an intact subscapularis,8 further supported with long-term outcomes demonstrating that internal rotation force and range of motion are not maintained over time.9

When the patient re-presented with an acute pectoralis tear, we queried the literature for consideration of transfer of the ruptured PM if the subscapularis was in fact irreparable. However, we were unable to find any reports of transfers being performed in the setting of acute PM tear. An alternative transfer option was to repair the pectoralis primarily and perform a latissimus dorsi transfer; however, despite a recent systematic review citing potential benefits to latissimus over PM,1 the morbidity associated with taking an additional tendon when a suitable candidate is already available is hard to justify. Ultimately, after sufficient release of the subscapularis, we were able to perform primary repair of both injured tendons, making tendon transfers unnecessary. Nevertheless, if we had been unable to perform a primary repair, our plan was to attempt a primary PM tendon transfer with the caveat being that if the tissue quality of the PM tendon was concerning, a latissimus dorsi tendon transfer would instead be undertaken for the subscapularis, with primary repair of the PM tendon. These scenarios raise several interesting and as of yet unanswered treatment considerations.

In summary, our patient sustained a unique shoulder injury and underwent successful primary repairs of both the chronic subscapularis tear and acute PM tear regaining both excellent strength and range of motion. He remains on active-duty service with full active shoulder range of motion and participated in rock climbing without pain or limitation. In cases similar to ours where primary repair of the subscapularis is not possible, surgeons shoulder consider performance of a PM transfer, wherein the torn sternocostal head is routed deep to the clavicular head and attached to the lesser tuberosity. Alternatively, if concerns arise regarding PM transfer, latissimus dorsi transfer could be considered. This case underscores the importance of tailoring the surgical approach to the individual patient and being prepared to execute a variety of surgical techniques and by doing so, hopefully ensure the continued medical and force readiness of the military.

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SMARTQC

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