Be especially vigilant for ECS when patients come in with a history of shin splints. Sometimes, in these cases, ECS is the more accurate diagnosis.
It has been well established that shin pain is often caused by excessive pronation with eccentric contraction of the soleus muscle or traction of the soleus muscle away from the periosteum of the bone. This may cause injury to the muscle or disruption of the periosteal lining or Sharpey’s fibers where they insert into the bone. This may even eventually lead to micro- or stress fracture of the bone.
In my practice, I ask these patients if they have pain when walking. If their legs hurt while walking the day after the activity, then I look for a stress fracture with an X-ray and/or bone scan. Also keep in mind that the posterior tibial muscle tendon or other medial leg musculature are commonly involved with shin pain.
Patient may also have anterior muscle pains (possibly related to running uphill, sprinting, or overworking of the anterior tibial muscle against tight calf musculature) or are suffering from shock absorption issues. Shock absorption is particularly problematic for those who have rigid foot types (especially cavus feet). For these individuals, a change of playing surfaces or switching to more cushioned shoe gear is in order.
Yet you should also be on the lookout for more obscure causes of leg pain. For example, ECS and popliteal artery entrapment syndrome share very similar symptoms. For the latter condition, the pain is most prevalent during exercise activity, is severe and commonly occurs in the calf area. As with ECS, the intense pain subsides with rest.
Proceed with diagnostic testing, including arteriography and duplex scanning, to better evaluate the course and function of the popliteal artery. You may also want to perform non-invasive vascular testing to rule out claudication symptoms associated with the vascular pathology, especially in older athletes.
Another anomaly which causes ECS is an accessory soleus muscle or accessory peroneus quartus muscle. In my practice, I have seen many cases of recalcitrant posterior leg pain which mimics chronic Achilles tendonitis, but also mimics posterior compartment syndrome during activity.
I have identified several of these cases by looking at the overall contour of the distal calf and Achilles area. If you suspect hypertrophy or if the pains to the posterior leg are out of proportion to normal muscle soreness, order an MRI to determine if an accessory muscle is present. Obviously, an extra muscle within any compartment would cause increased pressures upon the adjacent soft tissues. When this is problematic, debulking or cutting of the surrounding fascia is often indicated.
How To Test And Treat Exertional Compartment Syndrome
When patients experience intense pain, a burning sensation, tightness and/or numbness in the lower extremities during exercise activity, and the pain usually resolves quickly once the patients stop the activity, you may be looking at exertional compartment syndrome (ECS). ECS is certainly one of the more confounding conditions as differentiating between the various leg pains can be difficult.
Parasthesia to the anterior leg, ankle or between the first and second metatarsal is indicative of anterior leg compartment involvement. In addition, weakness of ankle dorsiflexion or a drop foot also involves the anterior compartment. If you find parasthesia to the arch or plantar aspect of the foot, that is associated with deep posterior leg compartment involvement. Most of the time, however, numbness is not evident. Approximately 80 percent of ECS cases involve both legs.1
Other physical findings may include mild edema, muscle herniations over the involved compartment and muscle weakness in the specific compartment.
Several studies have been done to understand the pathophysiology of ECS. Mubarak studied acute compartment syndrome and concluded that the blood flow through the intracompartmental capillaries (capillary ischemia) is impeded, but blood flow continues to larger arteries and veins with palpable pulses distally.2 The extent of capillary ischemia in ECS is unknown.
In a subsequent study performed with magnetic resonance imaging, researchers found that ECS is not related to ischemia, but is actually due to increased fluid content (water) within the muscle compartment.3 This can compromise or impair function of the muscle or nerve within a tight and constricted fascial covering.
My personal observations through clinical and surgical intervention are that some individuals are genetically predisposed due to their anatomical muscle composition. Someone who is born with good muscle development/tone may actually wind up with hypertrophic muscle(s) as a result of repeated exercise activities. Muscle volume may expand 20 percent during exercise from both increased capillary infiltration and blood content. Ultimately, this intracompartment swelling increases the pressure within the enclosed compartment.
I believe there’s a similarity between this intracompartmental pressure problem of the leg and that which is present in tarsal tunnel syndrome cases. Here, there is an impingement of a nerve by surrounding hypertrophic muscle(s) or fluids within the medial ankle area. If the athlete persists in playing a sport with the pain, he or she may have the nerve impingement and symptomatic numbness or muscle weakness described above.
This is just one example. There are other differential diagnoses that you should consider when seeing symptoms of ECS (see “Why The ECS Diagnosis Is Often Missed” on page 24).