SUMMARY A rare acute injury caused by avulsion of the pectoralis major tendon and usually seen in weightlifters. Diagnosis is generally made clinically and is confirmed with MRI studies. Treatment is usually surgical repair when presenting acutely. Epidemiology Incidence rare injury (< 1 per 100,000 per year) that is increasing in incidence 75% of all reported cases have occurred since 1990 Demographics almost exclusively seen in males (20-40 years of age) often occurs in weightlifters commonly during bench-pressing Location most commonly occurs as a tendinous avulsion sternocostal head insertion of the pectoralis major tendon is the most common site of rupture Risk factors anabolic steroid use Etiology Pathophysiology mechanism excessive tension on a maximally eccentrically contracted muscle login to view 1 more bullet tendon fails in a predictable sequence login to view 4 more bullets Anatomy Pectoralis major innervation lateral pectoral nerve (C5-C7) login to view 1 more bullet medial pectoral nerve (C8-T1) login to view 1 more bullet origin (two heads) clavicular head login to view 1 more bullet sternocostal head login to view 2 more bullets insertion humeral shaft just lateral to the bicipital groove action shoulder adduction and internal rotation, to a lesser extent forward flexion (chiefly the clavicular head) other one of four muscles connecting the upper limb to the thoracic wall login to view 4 more bullets Biomechanics inferior fibers of sternal head at maximal stretch during final 30 degrees of humeral extension position at which pectoralis major is most vulnerable to rupture (as with bench pressing) Classification Modified Tietjen (Anatomic) Classification Type Description I Muscle contusion or sprain II Partial tear III Complete tear (further subclassified by location) Location III-A Muscle origin III-B Muscle belly III-C Musculotendinous junction III-D Intra-tendinous rupture III-E Tendon avulsion off humerus (no bone) III-F Bony tendon avulsion off humerus Presentation History patient may report a sudden pop or tearing sensation with resisted adduction and internal rotation Symptoms pain and weakness of shoulder Physical exam inspection & palpation swelling and ecchymosis of anterolateral chest wall and/or proximal medial brachium login to view 1 more bullet "dropped nipple" sign login to view 1 more bullet palpable defect and loss of anterior axillary contour login to view 1 more bullet motion & strength weakness most pronounced in adduction and internal rotation login to view 1 more bullet Imaging Radiographs indications limited utility recommended views standard shoulder trauma series (true AP, scapular Y, and axillary lateral) findings most often normal may show loss of pectoralis major shadow or bony avulsion MRI indications investigation of choice login to view 1 more bullet views requires dedicated sequence (standard shoulder MRI will not capture adequately) T2 sequence better for acute injuries T1 for evaluating chronic injuries findings useful in identifying the location and extent of the rupture (partial versus complete) login to view 2 more bullets Treatment Nonoperative initial sling immobilization, rest, ice, NSAIDs, physical therapy indications login to view 2 more bullets outcomes login to view 2 more bullets Operative open primary repair indications login to view 2 more bullets outcomes login to view 3 more bullets reconstruction indications login to view 3 more bullets outcomes login to view 2 more bullets Techniques Initial sling immobilization, rest, ice, NSAIDs, physical therapy technique sling in adduction and internal rotation, begin passive range of motion immediately as tolerated active assisted and active motion over the first 6 weeks transition to strengthening and unrestricted activity at 2-3 months Open primary repair approach standard deltopectoral approach repair technique all repair techniques have been shown to have comparably excellent success login to view 6 more bullets Reconstruction approach standard deltopectoral approach mobilization need to release adhesions superficial and deep to pectoralis major login to view 1 more bullet supplemental fascial release may be necessary to mobilize the muscle belly in chronic situations graft options Achilles allograft (most common) login to view 2 more bullets Gracillis weave (allograft versus autograft) Complications Re-rupture (5-7%) failure most often occurs at suture-tendon interface Persistent pain incidence most common complication Residual weakness Cosmetic deformity