VCOM Carolinas Research Day 2023

Clinical Case-Based Reports

Myotendinous Rupture of Pectoralis Major: A Case Report E. Casey Anders, OMS-II. Chinedum Nkemakolam, OMS-II. Lindsay Tjiattas-Saleski, DO, MBA, FACOEP Edward Via College of Osteopathic Medicine, Spartanburg, SC.

Abstract # CBR-5

Introduction

Results

Conclusions

References Injury: • The sternal head passes underneath the clavicular head, becoming maximally stretched during abduction, external rotation, and extension 4 • Most ruptures affect the distal portion of the muscle (at the musculotendinous junction or insertion site) 4 History/Physical Exam: • Reported tight pulling sensation or audible sound with sudden pain and weakness at the time of injury 5 • Present with bruising, swelling, and cosmetic defects to the axilla, anterior chest, and upper arm on the injured side 1,6 • Notable loss of motion and strength during internal rotation 1 • Inspection of the chest wall may show unilateral bulging of the muscle or a dropped nipple 1 Diagnosis: • Comprehensive history and physical exam • A standard radiograph can exclude other contributing pathologies but is limited in evaluation • An ultrasound may expedite diagnosis but is unclear how accurate • MRI, the gold standard for diagnosis, can confirm a muscle tear, classify the type, assess the grade, and determine location of the injury 5,7 Treatment: • Surgical treatment, especially when completed within the first 8 weeks, has a significantly better outcome 2 • Non-surgical treatment consists of rest, ice, analgesics, and immobilization for three weeks prior to physical therapy 2,5 Prognosis: • Rehabilitation focuses on restoring range of motion, strength, and stability • 90% of surgically repaired injuries returned to sport 6 months post surgery, with 74% performing at the same level prior to injury 6 1. Haley CA, Zacchilli MA. Pectoralis Major Injuries. Clinics in Sports Medicine . 2014;33(4):739-756. doi:10.1016/j.csm.2014.06.005 2. Mooers B, Westermann R, Wolf B. Outcomes Following Suture-Anchor Repair of Pectoralis Major Tears: A Case Series and Review of the Literature. The Iowa Orthopaedic Journal . 2015;35. 3. Marsh NA, Calcei JG, Antosh IJ, Cordasco FA. Isolated tears of the sternocostal head of the pectoralis major muscle: surgical technique, clinical outcomes, and a modification of the Tietjen and Bak classification. Journal of Shoulder and Elbow Surgery . 2020;29(7):1359-1367. doi:10.1016/j.jse.2019.11.024 4. Kakwani RG, Matthews JJ, Kumar KM, Pimpalnerkar A, Mohtadi N. Rupture of the pectoralis major muscle: Surgical treatment in athletes. International Orthopaedics . 2006;31(2):159-163. doi:10.1007/s00264-006-0171-2 5. Durant E, De Cicco F. Pectoralis Major Tear . StatPearls Publishing; 2022. 6. Yu J, Zhang C, Horner N, et al. Outcomes and Return to Sport After Pectoralis Major Tendon Repair: A Systematic Review. Sports Health: A Multidisciplinary Approach . 2018;11(2):134-141. doi:10.1177/1941738118818060 7. Pectoralis Major Injuries - WikiSM (Sports Medicine Wiki). wikism.org. https://wikism.org/Pectoralis_Major_Injuries Acknowledgements A special thank you to our patient; thanks for letting us share your story.

• In 2015, there were less than 400 documented cases of pectoralis major muscle ruptures, with 76% of them occurring after 1990 1,2 • They commonly occur from either direct trauma or extreme tension on a muscle that is already extended, externally rotated, and eccentrically contracted, a movement typically seen during a bench press • From 2008-2014, the most common type of surgically repaired sternocostal head tears were complete myotendinous junction tears and complete tendon avulsion tears 3

Figure 1. Photograph of anterior arm and chest wall after initial injury

Patient Case

A 39-year-old male presented to the emergency department with right shoulder pain that occurred during a workout 2 days prior. At the time of injury he reported being on his last repetition of a bench press series with 345 lbs on the bar when he described what felt like “a braided rope being torn fiber by fiber” localized to the shoulder area. This sensation caused him to initially drop the bar, but there was no lasting pain. He later noticed weakness and found his right shoulder and upper arm to be swollen and bruised (Figure 1). At presentation, he was documented to have bruising on the right arm and chest wall, tenderness, edema, and decreased range of motion with external rotation and extension. The arm was noted to be neurovascularly intact and his pain level was rated at 7/10. An MRI of the right shoulder and humerus was ordered in the ER. The patient had no previous injury to this area. He has an extensive surgical history including a right knee meniscus repair in 2017, hemilaminectomy and microdiscectomy in 2018, gangrenous appendix removal in 2019, and L3-L4 fusion with prosthetic disc in 2020. His maintenance medications included gabapentin 600 mg BID, tramadol 50 mg, flexeril 10 mg, indomethacin 50 mg BID, and tylenol OTC prn. He has no pertinent past medical history. He smokes cigars daily and denies use of alcohol or illicit drugs. An MRI of the chest without contrast revealed a full thickness rupture of the right pectoralis major with medial retraction of redundant tendon stump within the sternal segment of the muscle and surrounding edema (Figure 2). The inferior segment of pectoralis major looked edematous, and there was relative sparing of the superior segment. The patient underwent surgical repair 22 days after initial injury. He started physical therapy 4 days post-surgery (26 days after initial injury). He denied pain post-surgery but did note right arm muscle cramping and limitations in ADLs.

Figure 2. MRI chest without contrast, coronal view. Note the arrow indicating the region of fluid accumulation near the attachment of the right pectoralis major

Figure 3. The pectoralis major is a large, superficial muscle laying in the anterior thoracic cage. The muscle flexes, adducts, and internally rotates the humerus 1

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