Rupture of the pectoralis major muscle is rare, with only approximately 150 reported cases in the literature since its first description by Patissier in 1822.^1,2 However, over half of these cases have been identified in the past 30 years. Initially associated with work-related accidents, this condition is now more common among weight lifters and athletes participating in strenuous activities. With society’s increased interest in fitness and sport it is likely that this injury may become more prevalent.

Operative treatment of a ruptured pectoralis major muscle ensures the best outcome in terms of patient satisfaction, strength, cosmesis, and return to athletic activity.^{1,2,3,4,5,6,7,8,9,10,11,12,13} A meta-analysis performed by Bak et al.¹ revealed 88% of patients treated surgically had excellent or good results versus 27% treated nonoperatively. Another study of 22 patients using objective isokinetic testing demonstrated that the peak torque in those treated surgically returned to 99% of that of the uninjured side compared to only 56% in the patients managed nonoperatively.¹⁴ Since the majority of ruptures occur at the myotendinous junction, emphasis of repair is placed on anatomic reapproximation of the ruptured tendon to its insertion site on the humerus. Several techniques for surgical repair have been described. Nevertheless, because of its rarity most results are based on only a few subjects. Furthermore, lack of standardized objective values makes it difficult to compare several of these techniques.

Schepsis et al.³ described a trough and drill hole technique using a modified Kessler grasping stitch for successfully repairing six acute injuries (less than 2 weeks after injury) and seven chronic injuries. Their results demonstrated an average overall 96% subjective rating in the acute group, 93% in the chronic group, and 51% in the nonoperative group. Objective isokinetic testing after treatment revealed 102% adduction strength in the acute group (when compared to the uninjured side), 94% in the chronic group, and 71% in the nonoperative group. Furthermore, there were no statistically significant subjective or objective differences between the acute or chronically injured patients.

This technique has also been described successfully in the treatment of a 13-year delayed repair and a rupture associated with an anterior shoulder dislocation.^15,16 Miller et al.¹⁷ reported successful repair of an acute complete tendinous rupture using bone anchors. The 19-year-old patient was able to return to collegiate football. Other authors have performed successful repairs by attaching the tendon to the humerus with periosteal sutures.^5,7,9

Another popular technique described in the literature is the reattachment of the ruptured tendon to the humerus with the use of heavy sutures and drill holes. Kretzler and Richardson⁸ achieved good success using two rows of drill holes at the site of insertion in 15 patients. Strength was fully restored in 13 of the patients, with the remaining patients reporting significant improvements. Two patients who were repaired approximately 5.5 years after the injury who did not return to full strength showed significant improvement via Cybex evaluation. One demonstrated an increase in horizontal adduction strength from 50% to 80%, and the other from 60% to 84%. Deformity and range of motion were also corrected. Similar results have been reported by other authors.^18,19 Muscle belly tears occur less frequently and can usually be treated conservatively. However, direct surgical repair has also been described with good results.⁷

Pectoralis major muscle tears can often be diagnosed clinically. The physician must have a good understanding of the typical history and findings on physical examination. Up to 50% of patients may be initially misdiagnosed or there may be a delay in accurate diagnosis.¹⁴ Patients often present with a history related to a specific incident where they report a tearing sensation at the site of injury with or without a “pop.” Furthermore, they describe a limited range of motion, swelling, ecchymosis, and weakness. Patients may self-treat this injury as a strain with rest and ice until swelling and bruising resolve and then seek medical evaluation secondary to persistent weakness and asymmetry.

Classical physical findings consist of ecchymosis and swelling over the arm and axilla, a palpable defect and weakness in adduction, and internal rotation of the affected arm (Fig. 20-1). Comparison should always be made to the uninjured side. The classical webbed appearance of a thinned out anterior axilla can be accentuated by abducting the arm 90 degrees. A visual deformity may be enhanced by contraction of the muscle or resisted adduction of the arm as the injured muscle retracts medially and occasionally pulls overlying soft tissue in cases where adhesions have formed. When all of these characteristics are present, one must assume a rupture has occurred. However, classical findings may be masked when there is moderate to severe swelling. Furthermore, the investing fascia of the pectoralis major muscle, which prevents further retraction of the ruptured tendon, may be present as a palpable cord and mistaken for an intact tendon (Carr et al., unpublished data, 2004). Imaging modalities may assist with diagnosis and help provide additional clinical information. Conventional radiographs should always be ordered to rule out any avulsions, fractures, or dislocations. The characteristic finding of a ruptured pectoralis major muscle would be soft tissue swelling and the absence of the pectoralis major shadow. Further evaluation would consist of magnetic resonance imaging (MRI), the modality of choice for a detailed assessment of this injury. We recommend axial cuts to include the contralateral pectoralis major muscle for comparison to the injured side (Fig. 20-2). MRI has been described to accurately determine the grade and site of injury with great sensitivity.^20,21,22