The lower extremity nerves, muscles, and blood vessels are grouped into 4 compartments surrounded by fascial tissue. The fascia holds the 4 compartments together, including the anterior, lateral, superficial posterior, and deep posterior compartments. The fascial tissue has limited expansion potential as each compartment is wrapped tightly. Traumatic injuries and bleeding can cause the compartments to swell, and without room to expand the pressure within the compartments can elevate. When compartment pressures increase to dangerous levels the vascular and nerve supply to the distal leg can be compromised. Without distal perfusion and an adequate blood supply, tissue can begin to die in the foot. Compartment syndrome most commonly occurs with tibial shaft fractures, although rarely seen (occurring in an estimated 2% of tibia fractures). Other causes of compartment syndrome may include bleeding disorders, crush injuries, tight dressings or casts, burns, and overexertion.1,2

It is crucial to recognize compartment syndrome as a surgical emergency. Classic early signs of acute compartment syndrome of the lower extremity include increasing pain out of proportion despite intravenous pain medication and severe pain with passive stretch of the ankle. If the patient’s clinical signs clearly indicate acute compartment syndrome, then emergent fasciotomy should be performed. If the diagnosis remains unclear and other treatments have failed (bivalving or removing a cast or splint, elevation, ice, and intravenous pain medication), then the compartments should be measured. The most common location for compartment syndrome is the anterior compartment, but all 4 compartments should be measured. When measuring the compartments, any measurement in which the diastolic pressure minus the compartment pressure is <30 mm HG indicates compartment syndrome.1,2

Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).

References

  1. Karadsheh M. Compartment syndrome. Available at: http://www.orthobullets.com/trauma/1001/leg-compartment-syndrome (Accessed on August 22, 2017).
  2. Olsen SA, Glasgow RR. Acute compartment syndrome in lower extremity musculoskeletal trauma. J Am Acad Orthop Surg. 2005;13:436-444.
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