Anterior compartment syndrome

Overview

Anterior Compartment Syndrome is a condition in which pressure builds up within the anterior compartment of the lower leg, leading to decreased blood flow and potential damage to muscles and nerves. The anterior compartment contains key structures such as the tibialis anterior muscle, deep peroneal nerve, and anterior tibial artery. This syndrome can be acute (a medical emergency) or chronic (typically exercise-induced and less urgent).

When not treated promptly—especially in acute cases—compartment syndrome can result in permanent tissue damage, limb dysfunction, or even loss of the limb.

Causes

The primary cause of anterior compartment syndrome is increased pressure within the confined fascial space of the anterior leg. This pressure compromises circulation and impairs nerve and muscle function.

Acute Causes:

• Fractures (especially tibial fractures)

• Severe muscle contusions or crush injuries

• Vascular injuries or bleeding within the compartment

• Reperfusion injury after prolonged ischemia

• Burns or overly tight casts/bandages

Chronic Causes (Chronic Exertional Compartment Syndrome - CECS):

• Repetitive exercise, especially running or jumping

• Muscle hypertrophy in athletes

• Abnormal fascial anatomy

Symptoms

Acute Anterior Compartment Syndrome (medical emergency):

• Severe pain in the front of the lower leg, out of proportion to injury

• Tightness or fullness in the anterior leg

• Paresthesia (tingling or numbness) in the web space between the first and second toes (deep peroneal nerve)

• Weakness in dorsiflexion (difficulty lifting the foot)

• Shiny, swollen skin over the anterior shin

• Pain worsened by passive stretching of the muscles

• Pulselessness and paralysis (late signs)

Chronic Exertional Compartment Syndrome (CECS):

• Gradual onset of aching or cramping in the anterior leg during exercise

• Symptoms resolve with rest

• Possible numbness, tingling, or foot drop during exertion

• No symptoms at rest or during routine activities

Diagnosis

Acute Compartment Syndrome:

• Clinical diagnosis based on history and physical exam—do not delay treatment for imaging

• Intracompartmental pressure measurement: Readings >30 mmHg or within 30 mmHg of diastolic blood pressure suggest compartment syndrome

Chronic Compartment Syndrome:

• Pre- and post-exercise pressure testing: Confirm elevated compartment pressure after exercise

• MRI or near-infrared spectroscopy (optional): May assist in diagnosis but not routinely needed

Treatment

Acute Anterior Compartment Syndrome:

• Emergency fasciotomy: Surgical decompression of the compartment to relieve pressure and restore circulation

• Delay in surgery can lead to irreversible damage, muscle necrosis, and functional impairment

Chronic Exertional Compartment Syndrome:

• Activity modification or cross-training

• Physical therapy and stretching programs

• Elective fasciotomy: May be considered in severe or nonresponsive cases

Prognosis

The prognosis depends on whether the condition is acute or chronic and how quickly it is treated.

Acute Compartment Syndrome:

• Good outcomes if fasciotomy is performed within 6 hours of onset

• Delayed treatment increases the risk of permanent nerve damage, muscle necrosis, contractures, or amputation

Chronic Exertional Compartment Syndrome:

• Most individuals recover fully with proper activity modification or surgery

• Recurrence is possible, but long-term outcomes after fasciotomy are generally favorable