Shoulder and Elbow cases pectoralis major muscle injury

A 29-year-old, left-hand-dominant male presents to clinic complaining of left arm and shoulder pain for the last three days. The patient is an avid weight-lifter and was doing the bench press when his arm began to bother him. He has been using ice and resting with mild relief but has not been able to use his left arm for anything more than carrying light-weight objects. He is also having difficulty with simple activities such as putting on his shirt. On physical examination, the patient has ecchymosis and a prominent cord-like structure on the anterior left axilla. He has significant weakness with left shoulder adduction and internal rotation. He has a negative Hawkins sign and a negative Yergason sign.

Based on the information obtained thus far, which of the following is the most likely diagnosis?

1. Rotator cuff tear

2. Pectoralis major muscle rupture

3. Ruptured biceps tendon

4. Poland syndrome

5. Pectoralis minor muscle rupture

 

Discussion

The correct answer is (B). A pectoralis major muscle (PMM) tear or rupture usually occurs in weight-lifters while performing the bench press, but it can occur during

any activity in which the arm is extended and externally rotated while under maximal contraction (eccentric loading force). Patients often present with pain, swelling, ecchymosis, weakness and loss of the axillary fold in the acute setting. In the chronic setting, the swelling and ecchymosis have typically subsided. They may report an audible pop or a tearing sensation. On examination, there can be an apparent continuous muscle or tendon that is mistaken for an intact PMM tendon, but this represents the fascia of the PMM that is continuous with the fascia of both the brachium and the medial antebrachial septum. This continuous fascia will examine as a cord-like structure as shown in Figure 2–78.

 

 

 

Figure 2–78

 

The sternocostal portion of the muscle is injured more often than the clavicular. A rotator cuff tear and biceps tendon injury are unlikely given the mechanism of injury and physical examination findings. In addition, this patient is young for a rotator cuff tear. Poland syndrome is the congenital absence of the PMM. Pectoralis minor muscle rupture is scarcely reported and would not have the same history and physical examination findings.

Radiographs were normal. What is the most appropriate next step in management?

1. Ultrasound

2. Computed tomography (CT)

3. Magnetic resonance imaging (MRI)

4. Radiographs of humerus

5. Radiographs of the contralateral shoulder

 

Discussion

The correct answer is (C). Although pectoralis major muscle (PMM) injuries are

primarily diagnosed clinically, MRI is the imaging modality of choice to evaluate a PMM tendon injury. The extent and location of the injury can many times be assessed with MRI. The Tietjen’s classification system can be used for PMM injuries. Type I is a contusion or sprain. Type II is a partial tear. Type III injuries are complete tears and further classified by anatomic location: III-A (muscle origin), III-B (muscle belly), III-C (musculotendinous junction), III-D (tendinous insertion). Further subclassification were suggested including III-E (bony avulsion from the insertion) and II-F (muscle tendon substance rupture). Type II and Type III injuries have been reported at rates of 9% and 91%, respectively. Among complete tears, type III-D has been reported as the most common (65%). Ultrasound is a reasonable alternative to MRI, particularly if its use means avoiding delay of surgical repair. Ultrasound is much more user-dependent. CT will not allow adequate soft tissue evaluation. Further radiographic evaluation is incorrect because a radiograph of the injured shoulder has already been obtained. The radiographic findings are often normal, but the clinician should look for bony avulsions. The characteristic findings on radiographs are soft tissue swelling and absence of the PMM shadow.

After evaluating the MRI, the patient is diagnosed with a complete rupture of the pectoralis major tendon (Fig. 2–79). What is the recommended first step in management?

 

 

 

 

Figure 2–79

1. Sling immobilization in adducted and internally rotated position, cold compression, analgesics, and plan for surgical repair in 4 to 8 weeks

2. Cold compression, analgesics, and follow-up for surgical discussion

3. Shoulder immobilizer, cold compression, analgesics, follow-up as an outpatient in 1 to 2 weeks for transition to range of motion (ROM) exercises

4. Active ROM exercises until follow-up for outpatient surgery in 1 week to avoid loss of strength and range of motion postoperatively

5. Take immediately to the operating room for repair

 

Discussion

The correct answer is (A). Regardless of how the injury is definitively treated (nonoperative or operative), the first step should be rest, ice, compression, and pain control. Surgery is indicated for all young, active patients. If the patient was able to injure the pectoralis major muscle (PMM), then they likely utilize the muscle and should have it repaired. There is no consensus on the timing of when to repair PMM injuries; however, it would make sense to delay for ecchymosis and swelling to subside. Some believe the ideal timing for the surgery is between 4 and 8 weeks after injury. Others feel that chronicity does not affect outcome of repair even when performed 13 years after injury. Nonoperative treatment is reserved for elderly patients, suspected partial or muscle belly ruptures, and for low-demand patients. Answers B and D would risk further retraction of the tendon into the muscle belly. Answer C represents an initial nonoperative management protocol and is inappropriate for this patient.

All of the following are reported complications of operative management of a pectoralis major muscle injury, EXCEPT?

1. Re-rupture of the pectoralis major tendon

2. Numbness in the distribution of C6

3. Postoperative infection

4. Heterotopic ossification

5. Hematoma

 

Discussion

The correct answer is (B). Numbness in the distribution of C6 has not been reported in pectoralis major muscle (PMM) injuries, and the more likely injury in the case of surgical treatment for a PMM rupture is disruption of lateral or medial pectoral nerves. The incidence of re-rupture of the tendon has been reported as high as 7.7%.

Answer C is incorrect because postoperative infection is considered one of the most concerning postoperative complications following PMM tendon repair because of the location. The axillary area lends itself to higher bacterial burden with an increased infectious risk. Heterotopic ossification and hematoma have both been reported as complications.

 

Objectives: Did you learn …?

 

Diagnose a pectoralis major muscle injury?

 

Understand which imaging modalities are available for the evaluation of a pectoralis major rupture?

 

Distinguish when to conservatively manage or surgically repair a pectoralis major injury?

 

Understand the initial management of a pectoralis major injury?

 

Understand some of the complications that may be associated with pectoralis major injuries?