summary Exertional compartment syndrome is an exercise-induced condition of the leg characterized by reversible ischemia to muscles within a muscular compartment. Diagnosis is made by obtaining compartment pressures at rest, during exercise and post-exercise. Treatment generally involves surgical fasciotomies of the compartments involved. Epidemiology Incidence second most common exercise induced leg syndrome behind medial tibial stress syndrome Demographics males >females often seen in 3rd decade of life runners or those who run a lot for their sport Anatomic location anterior leg compartment most commonly affected (~70%) anterior and lateral leg compartment affected in 10% posterior leg compartment involvement associated with less predictable surgical outcomes more frequently associated with popliteal artery entrapment syndrome (PAES) most common cause is the presence of an accessory head of the medial gastrocnemius muscle Etiology Pathophysiology biochemistry the local metabolism of the musculature cannot go fast enough to clear the metabolic waste products pathoanatomy vascular, advanced imaging, and histologic experiments have not provided clear evidence of the pathoanatomy of this condition may have lower density of capillaries compared to asymptomatic individuals fascial hernias have been identified with decompression 40% of people with exertional compartment syndrome have these facial defects, only 5% of asymptomatic people have such defects most common location is near the intramuscular septum of the anterior and lateral compartments, where the superficial peroneal nerve exits Presentation Symptoms aching or burning pain in leg patients can often predict how long the pain will last for after they stop exercise paresthesias over dorsum of foot symptoms are reproduced by exercise and relieved by rest symptoms begin ~ 10 minutes into exercise and slowly resolve ~30-40 minutes after exercise Physical exam may be normal decreased sensation 1st web space decreased active ankle dorsiflexion Imaging Radiographs useful to eliminate other pathology MRI not very helpful in establishing diagnosis can help eliminate other pathology Evaluation Compartment pressure measurement limb should be in relaxed and consistant position required to establish diagnosis three pressure should be measured resting pressure 1 minute post-exercise pressure 5 minutes post-exercise pressure some authors advocate for an additional measurement point 15 minutes post-exercise diagnostic criteria resting (pre-exercise) pressure > 15 mmHg immediate (1 minute) post-exercise is >30 mmHg and post-exercise pressure >20mmHg at 5 minutes post-exercise pressure >15 mmHg at 15 minutes Near-infrared spectroscopy can show deoxygenation of muscle showed return to normal within 25 minutes of exercise cessation Treatment Nonoperative activity modification indications rarely effective anti-inflammatories attempt these treatments for 3 months prior to operating Operative two incision fasciotomy indications refractory cases technique two incision approach lateral incision release anterior and lateral compartments 12-15 cm above lateral malleolus identify and protect superficial peroneal nerve may see fascial hernia medial incision used to release posterior compartments perform if needed based on measurements release at middle of tibia at posterior border endoscopic smaller incisions, similar complications outcomes not a "home run" procedure because symptoms are often multi-variable no studies directly comparing operative to non-opertative treatment options surgery is successful in >80% of cases for the anterior compartment deep posterior compartment success is lower (around 60%) Complications Nerve injury most commonly the SPN DVT Recurrence up to 20% at a mean of 2 years after fasciotomy because of fibrosis/scar formation risk factors: isolated compartment release