Tibia fractures, among others, might be complicated by a so-called compartment syndrome. What is compartment syndrome and how is it diagnosed, and treated?
Compartment syndrome is a clinical condition caused by increased pressure within an enclosed fascial space, potentially leading to ischemic damage of muscles and nerves.
The leg is a typical location affected by compartment syndrome because of its well-defined compartments: anterior, medial, superficial posterior, and deep posterior (Figure 1). These compartments are surrounded by thick fascia, which does not allow for significant volume expansion when there is an increase in pressure. Thus, the contents of the compartment can be compressed.
Compartment syndrome is caused most commonly by bleeding and extravasation of fluid as a consequence of bone and soft tissue damage (ex. tibial fracture). Other causes are compressive devices (casts and ACE wraps), IV infiltration (fluid infused directly into the compartment), and burns (tissue restriction). Some patients can also develop compartment syndrome after vascular repair, a so-called reperfusion injury.
Signs and Symptoms
The hallmark of compartment syndrome is “pain out of proportion to exam,” that is, pain that is more severe than expected given the injury/situation.
Even though one cannot know how much pain another person experiences, tracking the frequency at which patients request medication can give a quasi-objective measurement of the intensity of pain over time.
Likewise, because one would expect a decrease in pain once the injury is immobilized, a report of more pain after splinting would be alarming and considered “out of proportion” to what’s expected.
In advanced cases of compartment syndrome, a patient might develop what is known as the 6 P’s: pain, paresthesia (numbness), paresis (weakness of the affected area), pallor (pale skin), pulselessness (absent distal pulses), and poikilothermia (cold skin).
Diagnosis & Treatment
A key step in recognizing compartment syndrome is the physical exam. Examination might reveal swollen and shiny skin, and squeezing of the compartment will elicit exquisite pain.
Directly measuring the pressure of the compartments can be helpful in confirming the diagnosis. This is done by inserting a needle attached to a pressure meter. Ultimately, the decision to proceed with operative treatment is based on the overall clinical suspicion for compartment syndrome.
Treatment is fasciotomy, a procedure where long surgical cuts are made in the fascia to relieve the pressure. This must be done expeditiously, before the tissues under pressure are damaged irrevocably. The incisions are generally left open for 48-72 hours, at which point they can be closed in a second surgery.
If left untreated, the compartment’s pressure will prevent blood flow leading to damage of the muscle and nervous tissue. This can result in permanent nerve damage, loss of muscle function, and possibly lead to amputation.