Pectoralis Major Tendon Rupture
Pectoralis Major Tendon Rupture
Ramsey Shehab
Basics
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Most commonly refers to complete avulsion of the pectoralis tendon at the humeral insertion (1)
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Ruptures at the myotendinous junction, muscle belly, or bony avulsion are possible but less likely (2).
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Associated with weightlifting (bench press) mostly, but possible with falls as well as direct trauma to tendon (3)
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Pectoralis is a powerful adductor, internal rotator, and flexor of humerus.
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Main source of power to the torso during strenuous activity
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2 heads:
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Superior/clavicular: Originates at medial clavicle and upper sternum
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Inferior/sternal: Originates at distal sternum, external oblique fascia, costal cartilage of 1st 6 ribs
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Fibers converge, rotate 90 degrees, and insert lateral to bicipital groove on humerus.
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Innervation: Medial and lateral pectoral nerves
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Blood supply: Pectoral branch of thoracoacromial artery
Epidemiology
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1st reported in 1822 by P. Patssier
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Increasing incidence with increase in health and fitness activities
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More than 200 cases reported in medical literature
Risk Factors
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Medications:
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Steroid use: Muscle strength increases disproportionately to tendon strength leaving it vulnerable to injury (4).
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Corticosteroid injection: Weakens tendon structure
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Systemic diseases: Connective tissue disorders, collagen vascular disease, diabetes (1)
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Advanced age
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Disuse atrophy
Etiology
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Indirect mechanism most common with excessive tension on a maximally contracted muscle (5)
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Weightlifting (bench press specifically) is a common mechanism (3).
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Direct trauma to muscle in wrestling, rugby, and auto accidents also reported (4)
Diagnosis
History
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Men 20–40 yrs of age (2)
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Usually report a pop or tearing in the shoulder (2,4)
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Complain of pain/weakness in chest or shoulder (1,4)
Physical Exam
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Swelling and ecchymosis in anterior shoulder/chest most common (4)
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May have loss of axillary fold accentuated by abduction to 90 degrees (1)
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Shoulder motion limited by pain
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Weakness in abduction and internal rotation
P.453
Diagnostic Tests & Interpretation
Imaging
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Plain radiographs initially to rule out bony avulsions, fracture, or dislocations (1)
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Characteristic finding on x-ray is soft tissue swelling and loss of pectoralis major shadow (1)
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US can identify tears by uneven echogenicity and muscle thinning.
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MRI is optimal; assesses grade, muscle retraction, acuity, and presence of adhesions in chronic tears (3)
Differential Diagnosis
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Long head biceps subluxation
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Proximal humerus fracture
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Glenohumeral dislocation
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Rotator cuff tear
Treatment
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Acute treatment:
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Analgesics
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Ice
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Sling immobilization
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Long-term care:
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Tear type, patient age, activity level, and cosmetic desires determine care (1).
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Most partial tears, sternoclavicular tears, and muscle belly tears are treated nonsurgically (2).
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Complete sternal tears require surgical repair to restore function and strength (3).
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Conservative treatment may be enough in elderly/inactive population irrespective of type of tear (1).
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Ongoing Care
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Nonsurgical treatment:
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Begin shoulder mobilization and unresisted stretching when tolerated (1).
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Advance to resisted strengthening exercises at 6–8 wks post injury (1).
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Unrestricted activity at 3–4 mos after injury (2)
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Instruct in proper weightlifting technique to decrease re-rupture rate (5).
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Surgical management:
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Provides best outcomes in terms of patient satisfaction, strength, cosmesis, and return to sport (1,2)
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Acute repair within 8 wks is optimal (3).
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Delayed repairs do better than nonsurgical treatment (1).
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References
1. Petilon J, Carr D, Sekiya J: Pectoralis major muscle injuries: evaluation and management. J Am Acad Orthop Surg. 2005;13:59–68.
2. http://www.eorif.com/Shoulderarm/PectoralisRupture.html
3. Potter BK, Lehman RA, Doukas WC: Pectoralis major ruptures. Am J Orthop. 2006;35(4):189–195.
4. Hasegawa K, Schofer J: Rupture of the pectoralis major: a case report and review. J Em Med. 2008;01.025.
5. Dodds SD, Wolfe SW: Injuries to the pectoralis major. Sports Med. 2002;32:945–952.
Codes
ICD9
727.69 Nontraumatic rupture of other tendon
Clinical Pearls
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Usually a complete avulsion of pectoralis major tendon at humerus
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Most commonly occurs during weightlifting; specifically bench press
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Patients may report a pop and present with swelling, ecchymosis, and palpable tendon deformity.
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MRI is gold standard for diagnosis.
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Type of tear, patient age, and activity level dictate treatment.
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Surgical repair provides best outcomes in terms of strength, return to play, and patient satisfaction.