Pectoralis major tendon ruptures (PMTR), once a rare injury, have recently been rising in incidence, likely due to an increasingly active population with a growing interest in weight-training and use of anabolic steroids. This injury occurs almost exclusively in males. The pectoralis major is composed of two heads with separate origins. The smaller clavicular head arises from the anteromedial clavicle and often appears to be confluent with the deltoid muscle. The larger sternal head arises from the anterolateral sternum, ribs 1-6 and the external oblique aponeurosis. Both insert on the humeral shaft, lateral to the bicipital groove. The sternal head is at a mechanical disadvantage and is typically torn, while the clavicular head is often intact.
Petilon et al reviewed the diagnosis of PMTR. Complete ruptures are most often avulsions from the humeral insertion, which occur primarily during weight lifting (i.e. eccentric contraction during bench press). Patients often report a tearing sensation, with or without a pop. On exam, loss of normal axillary fold and chest wall contour as well as ecchymosis over the anterior chest and/or upper arm may be seen. Chest wall asymmetry can be accentuated by resisted adduction of the shoulder. Weakness in shoulder adduction is common. MRI is useful to confirm the diagnosis, differentiate complete from partial tears and determine tear location/retraction for surgical repair.
Butt et al reviewed the management of PMTR. Surgical repair of PMTR provides the greatest patient satisfaction, cosmesis and return to competitive sport. Nonsurgical management is only recommended for proximal tears at the sternoclavicular origin, some partial tears and in older, more sedentary patients. Prompt diagnosis is essential, as a delay can make primary repair difficult and necessitate the use of allograft for successful repair, which may have less favorable outcomes.