Muscle Strains and Tears

CHAPTER 122

Muscle Strains and Tears

Presentation

Strains are acute injuries to muscle-tendon units that result from overstretching or overexerting. Strains may occur in the trapezius or paravertebral muscles during a motor vehicle collision, with a whiplash-type injury to the neck. A strain can also occur in the anterior thigh, hamstring group, groin, or gastrocnemius muscle while a person is accelerating, running, or playing in a sport such as tennis. There may be an insidious development of pain and tightness, which is worse with use and better with rest. With more severe injury, such as a bicep-tendon rupture, the pain may be immediate and disabling. Tears of the muscle belly tend to be partial, with sudden onset of pain and partial loss of function. Often a tear occurs with considerable bleeding, which can lead to remarkable hematomas, causing swelling at the site and dissecting along tissue planes to create ecchymoses at distant, uninvolved sites. Complete tears are more likely in the tendinous part of the muscle. They can produce immediate loss of function and retraction of the torn end, creating a deformity and bulge.

What To Do:

Obtain a detailed history of the mechanism of injury. Elucidating an inciting event, determining the relieving and exacerbating factors, and timing of the pain can be the most important aspects of making an accurate diagnosis.

For cervical strains, see Chapter 103.

The anterior thigh (quadriceps) may be injured while the person is kicking, jumping, and sprinting. The hamstrings of the posterior thigh (biceps femoris, semitendinosus, semimembranosus, and adductor magnus) may tear during a powerful acceleration while a person is sprinting. Adductor strains of the groin occur during various sports activities, such as playing soccer or hockey. Calf muscle (gastrocnemius and soleus) strains are often seen with sudden accelerations from a dorsiflexed position. Upper arm (biceps) injury occurs with forceful lifting against resistance and with rupture of the long head of the biceps, usually presenting with anterior shoulder pain, possibly after hearing a “pop.”

Muscle strains may be classified as grade I (mild), grade II (moderate), or grade III (severe, in which the muscle is completely torn). Grade I strains are limited to local spasm and tenderness, and the patient may not notice the pain until the day after the injury. Grade II strains have a palpable area of tenderness and swelling. Passive stretching is usually painful. Grade III strains include tendinous rupture or midbelly tears that are usually accompanied by a visible and/or palpable defect or deformity.

Perform a physical examination that defines the muscle that is involved and rules out bony involvement and other possible disease.

Palpate the injured muscle, attempt active and passive range of motion, check for bony tenderness, and put proximal and distal joints through a range of motion in an attempt to elicit any joint pain (see Chapter 126 for specific evaluation of calf muscle strain).

Most strains can be easily diagnosed on physical examination, with pain on palpation of the involved muscle and pain on muscle contraction against resistance.

Without signs of bony injury, plain radiographs are of little value. Ultrasonography can be useful for diagnosing muscle and tendon tears if the diagnosis is in question.

When there is a need to know the extent of injury for treatment and prognostic purposes, MRI can be used to confirm and delineate muscle strain or tears, and partial and complete tendon tears.

Acute treatment of grade I and II strains should include relative rest and possibly short-term use of acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs). Cold packs with compressive soft splinting may be helpful when hemorrhage or swelling is present. Short-term use of opiates may be required for particularly painful injuries.

Even without hemorrhage or swelling, ice massage may be preferable to heat for providing comfort in the first 1 to 3 days. Freeze water in a small paper or Styrofoam cup, tear off the upper rim to expose the ice, and then massage the injured muscle with the ice, using slow, circular strokes for 5 to 20 minutes, using the cup as an insulator. It may be helpful to alternate heat and cold treatments and allow the patient to choose which is better for relieving pain or improving range of motion.

Severe grade II or grade III strains may require maximum immobilization with a rigid splint and/or with a sling or crutches. Midbelly muscular tears are often treated conservatively, but complete tears of the tendon’s insertion from the bone may require surgical repair.

The more severe strains require orthopedic consultation and follow-up for treatment and rehabilitation.

Most minor grade I strains will resolve within 2 to 4 weeks. Healing time for all strains can be extremely variable and prone to reexacerbations (especially hamstring injuries).

The second stage of therapy for most strains begins when the patient’s pain has subsided and should consist of gentle range-of-motion exercises, followed by progressive strengthening.

Warn the patient that partial tears can become complete after rehabilitation and that potentially alarming ecchymosis may develop in the days following the injury. They will change color and percolate to the skin at distant sites that are dependent to the injury.

What Not To Do:

Do not order radiographs when the injury is clearly isolated to a muscle or tendon and there is no bony involvement.

Do not prescribe muscle relaxants for acute muscular strain. One double-blind study demonstrated that adding cyclobenzaprine (Flexeril) to treatment with ibuprofen (Motrin) did not enhance pain relief but was associated with a higher rate of central nervous system (CNS) side effects.

Discussion

Groin injuries may result from a variety of causes. The most common groin injury in athletes is the abductor strain. Iliopsoas strain usually occurs during resisted hip flexion or hyperextension. Tenderness may be felt on deep palpation over the lateral aspect of the femoral triangle (adjacent to the femoral artery). This may be accentuated by having the patient raise his heel off the examining table to about 15 degrees.

High hamstring strains (partial avulsion of the muscle from its origin on the ischial tuberosity) occur when excessive stress is placed on the stretched hamstrings. Patients usually present with posterior thigh pain and can have radiation to the groin as well. The diagnosis is easily made when the examiner notes pain on palpation directly over the muscle insertion on the ischial tuberosity.

Sartorius strains lead to palpable tenderness over the anterior superior iliac spine.

Avulsion fractures and apophysitis should be considered in the skeletally immature pediatric age group.

The sports hernia presents as an insidious-onset, gradually worsening, deep groin pain that is diffuse in nature. It may radiate along the inguinal ligament, perineum, and rectus muscles. Coughing may increase the pain. Radiation of pain to the testicles is present in approximately 30% of afflicted men. On physical examination, no true hernia is palpable, because only the deep fascia is violated. MRI and bone scan might be helpful in ruling out other conditions (e.g., stress fractures), but not in making a definitive diagnosis of sports hernia. If symptoms persist after several weeks of conservative treatment, an athlete should undergo surgical exploration and repair.

Other potential causes of groin pain include the more common indirect and direct hernias; testicular disease, including torsion; hip disease, including avascular necrosis; and lumbar radiculopathy. Osteitis pubis, or pubic symphysitis, is a painful inflammatory condition involving the pubic symphysis and surrounding structures that is another possible cause for groin pain and is generally thought of as a self-limiting condition.

Potentially more serious intra-abdominal disease, including gastrointestinal (e.g., appendicitis), urologic (e.g., renal colic), and vascular (e.g., abdominal aortic aneurysm), can refer pain to the groin and should be considered when clinically compelling.

Rupture of the long head of the biceps is one of the most common musculotendinous tears. Proximal long-head tendon ruptures account for 96% of all biceps tendon ruptures. Rupture occurs more frequently in an aging population, specifically in patients who are older than 40 years, and generally occurs in tendinopathic tendons. Risk factors for biceps tendon ruptures include recurrent tendinitis, a history of rotator cuff tear, a history of contralateral biceps tendon rupture, age, poor conditioning, and rheumatoid arthritis.

The literature shows no clear consensus on the treatment of biceps-tendon rupture. Surgical repair tends to be favored in the younger and more athletic patient, whereas conservative, nonsurgical management is considered to be more appropriate in the middle-aged and older patient.

Overuse injuries affecting the medial aspect of the lower legs have traditionally been referred to as “shin splints.” This catchall diagnosis is gradually being replaced by that of medial tibial stress syndrome (MTSS). This condition predominantly affects running athletes. Patients who have MTSS typically present with shin pain that is related to running or jumping. Pain may be unilateral or bilateral. Examination of patients suffering from MTSS frequently reveals pain confined to the medial border of the tibia, although it can also be located laterally. Toe standing or resisted plantarflexion can exacerbate pain.

Rest is crucial for the treatment of MTSS. Ice, stretching, heel cups, NSAIDs, corticosteroid injection, and even crutches have been studied, but none has benefits that are greater than rest alone. Five to 7 days of rest are often enough to allow return to activity at a reduced intensity, gradually increasing loads to premorbid levels.

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