Compartment syndrome is where the pressure within a fascial compartment is abnormally elevated, cutting off the blood flow to the contents of that compartment.
Fascial compartments involve muscles, nerves and blood vessels surrounded by fascia. Fascia is a sheet of strong, fibrous connective tissue that encases the contents of the compartment. It is not able to stretch or expand.
Acute compartment syndrome is an orthopaedic emergency requiring surgery (fasciotomy) to relieve the pressure within the compartment and restore blood flow. Without prompt treatment, tissue necrosis (death) and permanent damage can occur.
Compartment syndrome can be classified as acute or chronic. Most of this section relates to acute compartment syndrome.
Acute compartment syndrome is usually associated with an acute injury, where bleeding or tissue swelling (oedema) associated with the injury increases the pressure within the compartment.
Presentation
Acute compartment syndrome most often affects one of the fascial compartments in the legs, but it can also affect the forearm, feet, thigh and buttocks.
It usually presents after an acute injury, particularly:
- Bone fractures
- Crush injuries
Acute compartment syndrome presents with the 5 P’s:
- P – Pain “disproportionate” to the underlying injury, worsened by passive stretching of the muscles
- P – Paresthesia
- P – Pale
- P – Pressure (high)
- P – Paralysis (a late and worrying feature)
Note that pulseless is not a feature, differentiating it from acute limb ischaemia. The pulses may remain intact depending on which compartment is affected.
TOM TIP: Disproportionate pain is a key characteristic of compartment syndrome. The pain is so severe that pain medications are not effective. If you see a patient with disproportionate pain after an injury in your exams, the diagnosis is probably compartment syndrome.
Management
Acute compartment syndrome is primarily a clinical diagnosis based on clinical signs and symptoms.
Needle manometry can be used to measure the compartment pressure. A device (manometer) measures the resistance to injecting saline through a needle into the compartment.
Initial management involves:
- Escalating to the orthopaedic registrar or consultant
- Removing any external dressings or bandages
- Elevating the leg to heart level
- Maintaining good blood pressure (avoiding hypotension)
Emergency fasciotomy is the definitive management. Ideally, this should be as soon as possible after injury (e.g., within 6 hours). If it is delayed, irreversible damage may occur, and fasciotomy may not be beneficial.
Fasciotomy involves a surgical operation to cut through the fascia, down the entire length of the compartment, and release the pressure. The compartment is explored to identify and debride any necrotic muscle tissue. The wound is left open and covered with a dressing.
Patients require repeated trips to theatre (every few days) to explore the compartment for necrotic tissue, which needs to be debrided. As the swelling improves, the wound can be gradually closed, which can take several weeks. A skin graft may be required if the wound cannot be closed around the compartment.
Chronic Compartment Syndrome
Chronic compartment syndrome (also called chronic exertional compartment syndrome) is usually associated with exertion. During exertion, the pressure within the compartment rises, blood flow to the compartment is restricted, and symptoms start. During rest, the pressure falls, and symptoms begin to resolve. It is not an emergency.
Symptoms are usually isolated to a specific location at the affected compartment. Symptoms include pain, numbness or paresthesia (pins and needles). They are made worse by increasing activity and resolve quickly with rest.
Needle manometry can be used to measure the pressure in the compartment before, during and after exertion to confirm the diagnosis. It may be treated with a fasciotomy.
Last updated August 2021