Smith, Tyler DO; Arevalo, Alfonso DO; Kazanjian, Jack DO
Philadelphia College of Osteopathic Medicine
Department of Orthopedic Surgery
Over the past two decades, there has been a significant increase in the number of pectoralis major muscle ruptures.1,2,6 These ruptures occur almost exclusively in athletic, muscular men aged 20-40 years old.1,2,3,4 The majority of cases occur during weight lifting, specifically bench press exercise, although there have been numerous reports of other demanding activities such as wrestling, rugby, football, boxing, and gymnastics.1,3,4,5,6 The predominance of pectoralis major tears occur as tendinous avulsion at the humeral insertion, however rarely rupture at musculotendinous junction or muscle belly. 2,3,4,6 We present a case of isolated sternal head rupture at the musculotendinous junction with simultaneous muscle belly segmental tearing treated with side to side repair. To our knowledge, there are no reports in the literature citing this type of rupture and its associated treatment.
The anatomy of the pectoralis major muscle is a key component to diagnosis and treatment of these injuries. The pectoralis major is composed of two heads, clavicular and sternal, with the sternal head comprising over eighty percent of the total muscle volume.1,2,3,4 The sternal head can be further subdivided along fascial planes into seven overlapping segments that converge to form a single multipennate muscle belly with a confluence at the muscle tendon junction (Figures A, B). 1,2,3 The sequence of failure, as proposed by Elmaraghy et al, suggests that tendon injury initially begins at the inferior segment, followed by more superior segments, and finally clavicular head.1,2
Figure A. Cadaveric dissection of the seven multipennate heads of the sternal head of the pectoralis major. Reprinted with permission from Elmaraghy AW, Devereaux MW. A systematic review and comprehensive classification of pectoralis major tears. J Shoulder Elbow Sure 2012;21:412;22.)
Figure B. Schematic representation of the multipennate sternal head of the pectoralis major muscle. Reprinted with permission from Elmaraghy AW, Devereaux MW. A systematic review and comprehensive classification of pectoralis major tears. J Shoulder Elbow Sure 2012;21:412;22.)
A 43 year-old active duty male police officer presented for initial outpatient evaluation following an altercation in the line of duty. While wrestling a suspect to the ground, he experienced a sharp “pop” in the axillary fold with subsequent weakness and deformity. Clinical examination revealed extensive ecchymosis to the left chest wall and lack of axillary muscle tone consistent with pectoralis major tendon rupture. Using magnetic resonance imaging (MRI), the suspected diagnosis was confirmed. After thorough discussion of risks, benefits, and alternatives of surgical repair, the patient elected to undergo acute repair in hopes to restore his function and allow him to return to active duty.
The operation was done in the beach chair position using the modified deltopectoral approach. Exposure of the sternal and clavicular heads of the pectoralis major tendon revealed an intact clavicular head. The tendinous insertion of the sternal head at the lateral aspect of the bicipital groove was intact. Tracing the insertion medially, a rupture was noted at the musculotendinous junction of the sternal head (Figure C). In addition, there were also four separate segments of the sternal muscle belly that experienced segmental tearing and separation. The segmental separations were then repaired from superior to inferior with #2 Fiberwire (Arthrex Inc., Naples, FL, USA) suture into a single unit in order to restore the multipennate anatomy of the muscle belly (Figure D and E). The muscle tendon junction was repaired using side to side repair with #2 Fiberwire in a Krackow fashion. Furthermore, it was reinforced with #5 Ethibond suture (Johnson & Johnson, Westchester, PA, USA). The fascial, subcutaneous, and incision were closed in normal fashion and the patient was immobilized in a sling.
Figure C. Intraoperative clinical photo demonstrating sternal rupture at musculotendinous junction.
Figure D. Intraoperative clinical photo demonstrating inferior and superior sternal head muscle belly segments that were repaired with side-to-side repair
Figure E. Intraoperative clinical photo of the sternal head muscle belly following side to side repair with Fiberwire suture.
Postoperatively the patient was immobilized in a sling. At ten days he began passive range of motion exercises with forward flexion as tolerated and external rotation limited to 40 degrees. At six weeks he began active assisted range of motion exercises with forward flexion and gradual increases in external rotation as tolerated to full motion. Isometric exercises to the pec tendon were allowed at eight weeks. At ten weeks light resistance exercises were started. At sixteen weeks he began aggressive scapular stabilization exercises and plyometric strengthening. He is approximately one year from surgery at this time and reports no pain or disability. His repair remains intact and he has no cosmetic deformity at the axilla. He has returned to active duty and is able to perform all activities without deformity or dysfunction.
Understanding the complex, multipennate anatomy of the pectoralis major is a key component to planning operative fixation. The sternal head is subdivided into seven separate muscular segments, with injury typically beginning at the most inferior segments due to their shorter length and lateral pennate angle.2,3 Ruptures at the muscle tendon junction most commonly occur as indirect injury mechanisms, such as forced abduction against resistance.4 Muscle belly tears are typically associated with direct trauma or crushing injuries.4 Elmaraghy et al, in a series of 365 patients, found that only 6.5% of pectoralis major tears occurred at the muscle belly.2 The same study also reported a 3.8% incidence of musculotendinous junction ruptures isolated to the sternal head.2 No simultaneous muscle belly and muscle tendon injuries were seen in their series, and to our knowledge, none have been reported in the literature.
Unfortunately, the patient in our case could not fully recollect the exact position of his upper extremity during the time of injury. Our hypothesis is a combination of direct trauma to the muscle segments and indirect trauma via forced hyperabduction and eccentric failure at the muscle tendon junction. Due to the novelty of this injury, there is no consensus treatment guidelines in the literature. Additional high-powered studies are needed to further subdivide and classify these injuries, however restoration of the natural anatomy of the pectoralis major muscle and tendon unit remains a key principle in treatment success.
- Butt, Usman, et al. “Pectoralis Major Ruptures: a Review of Current Management.” Journal of Shoulder and Elbow Surgery, 24, no. 4, 2015, pp. 655-662., doi:10.1016/j.jse.2014.10.024.
- Elmaraghy, Amr W., and Moira W. Devereaux. “A Systematic Review and Comprehensive Classification of Pectoralis Major Tears.” Journal of Shoulder and Elbow Surgery, vol. 21, no. 3, 2012, pp. 412-422., doi:10.1016/j.jse.2011.04.035.
- Lipman, Adam and Eric Strauss. “Treatment of Pectoralis Major Muscle Ruptures.” Bulletin of the Hospital for Joint Diseases, vol. 74, no. 1, Jan. 2016, pp. 63-72
- Petilon, Julio, et al. “Pectoralis Major Muscle Injuries: Evaluation and Management.” Journal of the American Academy of Orthopaedic Surgeons, vol. 13, no. 1, 2005, pp. 59-68., doi: 10.5435/00124635-200501000-00008.
- Pochini, Alberto De Castro, et al. “Clinical Considerations for the Surgical Treatment of Pectoralis Major Muscle Ruptures Based on 60 Cases.” The American Journal of Sports Medicine, 42, no. 1, 2013, pp. 95-102., doi:10.1177/0363546513506556
- Schepsis, Anthony A., et al. “Rupture of the Pectoralis Major Muscle.” The American Journal of Sports Medicine, 28, no. 1, 2000, pp. 9-15., doi:10.1177/03635465000280012701