Compartment Syndrome

Compartment syndrome (CS) is pain caused by muscles growing faster than the sheath surrounding them. When the perfusion pressure falls below the tissue pressure in a closed anatomic space the tissue circulation and function is compromised. Each muscle or muscle group is enclosed in a compartment bound by relatively rigid walls of bone and fascia. The muscle will feel tight, numb (if nerves are involved) and the patient may have a sensation of pressure due to excess fluid or muscle development. The pain is on the outside of the forearm and comes on during exercise and lasts well beyond the finish of the session. The compartments of the lower leg and the forearm are particularly prone to developing elevated compartment pressures.

CS causes include any long-bone fracture, vascular injury, compression in the setting of a crush injury, a tight cast or dressing. Late manifestations of CS include the absence of a distal pulse, extremity paresis, and hypoesthesia. If CS is strongly suspected in the clinical examination, operative decompression is the mainstay of therapy. Compartment-pressure measurements are usually reserved for diagnosing chronic CS, for evaluating comatose patients, or for other conditions in which the clinical examination findings are equivocal. Although rhabdomyolysis and subsequent renal failure are among the most severe life-threatening complications, Volkmann contractures, a permanent flexion contracture of the hand at the wrist, resulting in a claw-like deformity of the hand and fingers, is one of the more commonly observed limb deformities. Fibrosis and contracture of the flexor compartment pulls the fingers into flexion and the wrist into flexion and pronation. However, active extension of the fingers is possible when the wrist is passively flexed indicating that the contracture is in the forearm. Damage to the median nerve may result.

Compartment syndrome (CS) occurs whenever increased tissue pressure in a myofascial compartment compromises blood flow to the muscles and nerves within that compartment, resulting in tissue and nerve damage. Two types of CS have been identified, acute and chronic.

Acute CS typically occurs subsequent to a traumatic event, most commonly fractures. Symptoms worsen acutely, and irreversible nerve injury and muscle necrosis occur within hours. Chronic CS is a recurrent syndrome that occurs with exercise or work and is usually observed in competitive or collegiate athletes. Often, it occurs bilaterally, and the pain it causes may be reproducible at a specific exercise distance or time interval. Symptoms tend to subside within one hour of terminating the activity and are minimal during normal daily activities but return when athletic activity that caused the initial problem is resumed. Chronic CS is usually observed in long-distance runners, basketball players, skiers, and soccer players. This condition is usually the result of minor trauma or repetitive overexertion.

For chronic CS, muscle bulk increases 20% during exercise and contributes to the transient increase in intracompartmental pressure. Repetitive muscle contraction alone can increase intramuscular pressure to levels that may cause transient ischemia. Chronic CS occurs when the pressure between successive contractions remains high and impedes blood flow. As the pressure rises, arterial flow during muscle relaxation decreases, and the patient experiences muscle cramping. The anterior and lateral compartments of the lower leg and forearm are commonly affected; the deep and posterior compartments are less commonly involved.