Exertional Compartment Syndrome

A strong index of clinical suspicion is needed to rule out ACS and AECS; it is particularly crucial given the latter condition occurs in the absence of a traumatic injury or fracture.  AECS is essentially a hybrid of ACS and CECS and is often overlooked or diagnosed in a delayed fashion.  AECS patients often present following sport-related activity or exertion with nonspecific leg pain during and often persisting after strenuous or repetitive activity.  CECS clinically differentiates in that symptoms will predictably abate following activity cessation.  While CECS is often a diagnosis of exclusion, AECS should be ruled out first before considering other diagnoses, which one accomplishes by measuring the patient's compartments in question.

The diagnosis of CECS has its basis in a thorough clinical history, paying particular attention to a patient's characterization of pain during strenuous activity,  well-localized to a specific compartment and the pain/symptoms disappear quickly after the cessation of activity.[2]  Patients will generally complain of discomfort that they describe as squeezing, cramping, aching or burning that typically begins within 15 to 20 minutes of an exertional type activity, i.e., running, marching, etc.[5][6]  The discomfort resolves completely with rest, although the duration may vary.  

In 70 to 95% of cases, the pain is bilateral.[5][6]  Generally, the physical examination is unremarkable as patients do not undergo evaluation during or immediately after exercise.  If this condition is suspected, a physical examination should take place pre- and immediately post-exercise.[5]  After exercise, the affected compartment may be tender, bulge, or feel tight.  Passive stretching of the involved compartment may elicit pain.  Additionally, there may be focal neurological findings, i.e., decreased sensation, paresthesias, or weakness.[6]

Formal CECS testing following stress-testing gets confirmed by compartment pressure measurements before and after exercise utilizing the Stryker pressure monitoring system as described previously.[21]  Upon obtaining baseline measurements with the patient resting supine, the patient is often asked to perform a period of exercise activity in a controlled environment to facilitate later post-testing.  A common exercise period consists of running on a treadmill with a minimal degree of incline until the onset of severe symptoms. At that time, the patient rests for 5 minutes, followed by the measurement of compartment pressures.

History is key to suspecting this diagnosis as this condition is easy to overlook or fail to consider. Once CECS is suspected, diagnosis is confirmed by dynamic intra-compartmental pressure measurement at rest and then after exercise.[5] 

The Pedowitz criteria are often used to obtain or rule out a diagnosis of CECS in each compartment of interest[22]:

• A resting pressure of greater than or equal to 15 mmHg and/or a pressure of greater than or equal to 30 mmHg at 1 min post-exercise in any compartment, and/or;
• Post-exercise pressure greater than 20 mmHg at 5 minutes post-exercise

Just as in the setting of ACS, emergent fasciotomies must be performed in a patient presenting with AECS.  Otherwise, CECS is typically managed nonoperatively for a one- to three-month duration and surgical management may often be delayed and/or electively performed after having a discussion with the patient (or athlete) regarding the ideal timing given the athletes current sport-specific requirements.

Conservative management consists of rest, activity modification, stretching, orthotics, and physical therapy, but these measures are generally ineffective.[6] Nonoperative modalities include, but are not limited to:

• NSAIDs
• Botulinum toxin injections
  • Limited efficacy
• Gait training
  • Diebal et al. published two case series of patients with CECS prospectively treated with a gait training optimization program focusing on forefoot strike patterns[23][24][23]:
    • One study analyzed 10 study participants, concluding that none of the ten subjects required surgery at 1-year post-intervention

In refractory cases, or following at least a multiple month trial of nonoperative management modalities, operative management is discussed keeping in mind the patient/athlete's expectations for return to baseline activity and/or sport.[25][26]

Open fasciotomy is the predominant technique. However, other minimally invasive endoscopic techniques are also options.[27] The latter may include a smaller incision; by comparison, however, complication rates are reportedly similar in the literature 

In general, for the lower leg:

• Dual incision technique
  • Lateral[28]:
    • Anterior and lateral compartment access for release
    • 12 to 15 cm proximal to the lateral malleolus
    • Caution to protect/avoid the SPN
  • Medial[29]:
    • Superficial and deep posterior compartment access for release
    • Release at the middle of the tibia along the posterior border

The differential diagnosis for CECS can be quite broad.  Most commonly, CECS initially gets misdiagnosed as shin splints or medial tibial stress syndrome (MTSS).[30] 

Other considerations include[10]:

• Vascular pathologies
  • Intermittent claudication
  • Popliteal artery impingement.
• Tibial stress fractures
• Tendon pathologies (tendinitis, tendinosis, or tendon rupture)
• Nerve entrapment

In general, patients with isolated anterior and/or lateral compartment (over 80%) involvement generally report superior outcomes compared to their deep posterior compartment counterparts (60%).

Campano et al. in his systematic review of 24 articles showed a 66% success rate and an 84% satisfaction rate (short and mid-term follow up) after surgical repair.[27]  Beck et al. in his retrospective study of 155 pediatric patients showed a 79.5% return to sports rate with 18.8% requiring additional surgical revision.[25]  Prognosis also depends on the involved compartment as the anterior compartment (the most common location) has better outcomes.  Additionally, a single compartment CECS has a better surgical success rate than CECS involving multiple compartments.[27]

Where CECS is a relatively benign condition characterized by resolution of symptoms with rest, AECS is a true surgical emergency where the symptoms do not resolve.[7]  Like CECS, AECS correlates with repetitive type activities such as endurance sports, military training, and not associated with acute trauma.  This condition typically affects adolescent and young men.[7][31]  Some believe that this population is at risk secondary to the developing muscle mass in a restrictive fascial space.  Like CECS, there are elevated compartment pressures, but in AECS, it can result in irreversible myonecrosis and nerve injury.[7][31]  Treatment is surgical intervention with fasciotomy.  Unfortunately, because this entity is rare, and there is a lack of familiarity with this diagnosis, intervention is typically delayed.[7][31]  The key to making the diagnosis is awareness of this entity.  The examination is significant for pain out of proportion, and pain with passive stretch.  Tenderness remains generally isolated to the affected compartment. Pressure measurement can confirm the diagnosis.  Normal pressures are between 0 and 8mmHg.  An intracompartmental pressure of 30mmHg or a delta pressure less than 30mmHg (delta pressure = diastolic blood pressure - compartment pressure) is an indication for fasciotomy.  It is worth mentioning that if a Stryker intracompartmental pressure monitor is unavailable, an 18g or 20g needle or catheter can be attached to an arterial line monitor to determine pressures.[32]

Knowledge is key.  In the setting of an underdiagnosed and easily missed clinical entity, educating providers and patients is paramount.  Any patient that with a history of exertional extremity pain which resolves with rest should trigger consideration of CECS and seek medical attention.  Additionally, any patient with atraumatic extremity pain with findings of the pain out of proportion, pain on a passive stretch, and tender compartments merits consideration of AECS and should seek care.

Exertional compartment syndrome (ECS) requires awareness by a multitude of providers in various fields.  Physical therapists, advanced providers, nurses, and physicians may all encounter this entity in fields like primary care, emergency medicine, sports medicine, and orthopedics.  These various disciplines need to work collaboratively across interprofessional lines to help bring about optimal outcomes for these patients. [Level V] Ultimately, once suspected, the condition would need confirmation and definitive management with surgical fasciotomy by a specialist like an orthopedic surgeon.  Primary care and emergency medicine practitioners must be especially aware of the limb-threatening form of acute exertional compartment syndrome (AECS).