Compartment Pressure Testing

Key Points

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Chronic exertional compartment syndrome (CECS) is a painful condition characterized by an increase in intracompartmental pressure (ICP) with exercise.
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This is seen most commonly in the four muscular compartments of the leg but has also been described in the foot, the four compartments of the arm, and the hand. ^,This chapter focuses on compartment pressure testing for the leg, but the principles can be applied to the other locations.
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Preexercise and postexercise ICP is the “gold standard” test to diagnose CECS.
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Compartment pressures are obtained by inserting an ICP monitor with palpation guidance into the four compartments of the leg.
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ICPs are obtained prior to exercise and at 1 minute and 5 minutes post exercise.
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CECS is confirmed using the Pedowitz criteria if the preexercise ICP greater than 15 mm Hg, 1-minute postexercise ICP greater than 30 mm Hg, or 5-minute postexercise ICP greater than 20 mm Hg.

Pertinent Anatomy

The leg contains four distinct compartments: anterior, lateral, superficial posterior, and deep posterior. The anterior compartment contains the tibialis anterior muscle, extensor hallicus longus muscle, extensor digitorum longus muscle, peroneus tertius muscle, deep peroneal nerve, and the anterior tibial artery and vein. The lateral compartment contains the peroneus longus muscle, peroneus brevis muscle, and superficial peroneal nerve (which exits through the fascia of the lateral compartment in the distal third of the leg). The superficial posterior compartment contains the plantaris muscle, gastrocnemius muscle, soleus muscle, sural nerve, and branches of tibial artery and vein. The deep posterior compartment contains the flexor digitorum longus muscle, tibialis posterior muscle, flexor hallucis longus muscle, popliteus muscle, tibial nerve, posterior tibial artery and vein, and the peroneal artery and vein. The tibialis posterior muscle is contained in its own fascia and is sometimes referred to as the fifth compartment of the leg.

Common Pathology

Chronic exertional compartment syndrome (CECS) most commonly affects the anterior (40% to 60%) and deep posterior compartments (32% to 60%), followed by the lateral (12% to 35%) and superficial posterior compartments (2% to 20%). Thickened and less-compliant compartment fascia, reduced microcapillary capacity, and venous congestion have all been postulated to contribute to the development of CECS, but the pathophysiology is still debated.

In normal muscle physiology, there is a 20% increase in muscle volume during exercise and, as a result, intracompartmental pressure (ICP) increases. In CECS, increased compartment pressure during exercise may also lead to transient neuropraxia manifesting as transient changes in sensation and strength. The neurologic symptoms are related to the nerve contained in the effected compartment. CECS involving the anterior compartment may present with deep peroneal neuropraxia with foot drop and first web space numbness that progressively develops with activity. CECS of the lateral compartment may present with activity-related progressive ankle eversion weakness and dorsal foot numbness. CECS involving the superficial and/or deep posterior compartment may present with activity-related progressive plantar foot paresthesias and ankle plantar flexion weakness.

The differential diagnosis for CECS includes medial tibial stress syndromes, stress fracture, fascial defects or herniations, popliteal artery entrapment syndrome, claudication, peripheral nerve entrapment syndromes, and lumbosacral radiculopathy. Clinical suspicion will guide the work-up, but ICP testing is the “gold standard” test to confirm the diagnosis of CECS. Normally, increases in compartment pressures return to normal within 3 to 5 minutes after exercise. A delay in normalizing pressures or pre-exercise pressure measurements greater than 15 mm Hg are suggestive of CECS. The Pedowitz criteria ( Table 29.1 ) are the established gold standard for diagnosing CECS.

TABLE 29.1

Pedowitz Criteria for the Diagnosis of Chronic Exertional Compartment Syndrome by Intracompartmental Pressure.