Traumatic Muscle Injuries

CHAPTER 32

Traumatic Muscle Injuries

Muscle Contusions

• Contusions are the second most common type of muscle injury, after muscle strain.

• Contusions are caused by direct, non-penetrating blows to a muscle belly, which leads to bleeding in the muscle and hematoma formation.

• Most common locations are the quadriceps (anterior or lateral thigh) and brachialis (upper arm).

• They occur most frequently in contact and/or collision sports such as American tackle football, rugby, soccer, and martial arts.

• Almost all resolve with rest, ice, compression, and elevation (RICE) in combination with rehabilitation exercises.

Quadriceps Contusion

INTRODUCTION/ETIOLOGY/EPIDEMIOLOGY

• Quadriceps are the most common location for muscle contusion.

• A blunt contact of a knee to the thigh is the most common mechanism of injury.

SIGNS AND SYMPTOMS

• Pain and swelling in the anterior or lateral thigh is worse with movement; bruising may be visible.

• The patient may report knee stiffness and difficulty bearing weight.

• Physical examination findings include tenderness, edema, ecchymosis, weakness, and pain with passive stretch of the quadriceps muscle.

• A palpable mass may be present if the intramuscular hematoma is substantial.

• Active straight-leg raise will be painful and may be impossible for the patient to perform.

• One grading system for contusion severity is based on the degree of active knee flexion post-injury.

— Mild: active knee flexion greater than 90 degrees

— Moderate: active knee flexion between 45 and 90 degrees

— Severe: active knee flexion less than 45 degrees

DIFFERENTIAL DIAGNOSIS

• Quadriceps strain

• Femur fracture

• Morel-Lavallee lesion

• Bony or soft tissue tumor

• Hip pointer

DIAGNOSTIC CONSIDERATIONS

• The diagnosis can be determined clinically.

• If the history is unclear or atypical, imaging may be helpful.

• Radiographic findings are normal in the setting of an acute muscle contusion.

• Ultrasonography may be used to measure hematoma size to help determine if surgical evacuation should be considered in a high-level athlete.

• Magnetic resonance imaging (MRI) can provide detailed characterization of the lesion.

— MRI is typically ordered when there is concern for higher level muscle tear, consideration of surgical treatment, or prolonged failure of conservative treatment.

— MRI is especially helpful in identifying small hematomas deep within the muscle belly, when ultrasonography is inconclusive.

TREATMENT

• RICE

• Immobilization of the knee in maximal tolerable flexion (see Figure 32-1) for the first 24 to 48 hours after diagnosis facilitates healing, reduces the risk of complications by limiting the size of hematoma formation, and results in faster return to sports and activities.

• After 24 to 48 hours, active quadriceps stretching and isometric strengthening should begin in a pain-free range, while continuing the use of a compression wrap around the thigh only (without the knee included in flexion).

• Crutches should be used until there is at least 90 degrees of knee flexion and no limp.

• The athlete may return to play when knee flexion is full and pain-free and quadriceps size and strength are equal to the uninjured side.

• Athletes should wear a modified thigh pad to prevent reinjury.

EXPECTED OUTCOMES/PROGNOSIS

• Prognosis is excellent if treatment is begun promptly.

• In general, disability ranges from less than 2 weeks for mild contusions to greater than 3 weeks for severe contusions.

• In one study, following the protocol of immediate immobilization in knee flexion, the average time to return to play was 3.5 days, compared with 18 days when immobilization was delayed and 47 days when the thigh was wrapped with the knee in extension.

Figure 32-1. Immobilization of the knee immediately after quadriceps contusion.

Reproduced from LaPrade RF, Wijdicks CA, Griffith CJ. Division I intercollegiate ice hockey team coverage. Br J Sports Med. 2009;43(13):1000–1005. © 2009, with permission from BMJ Publishing Group Ltd.

Figure 32-2. Radiograph of the femur showing myositis ossificans in the quadriceps (arrow).

• Complications are more likely when treatment is delayed.

— Myositis ossificans, a benign proliferation of bone and cartilage at the site of the hematoma, is the most common complication (Figures 32-2 and 32-3).

■It should be suspected if a patient is not improving after 4 to 5 days of treatment or if symptoms, especially knee flexion, worsen 2 to 3 weeks after initial injury.