Exertional Compartment Syndrome in the Athlete,
-a commonly missed diagnosis
Michael M Cohen DPM FACFAS‘
When shin splints are not shin splints’
There many causes of leg pain in athletes. All too often, they are lumped together under the term shin splints which most sports medicine physicians do not considered a true diagnosis. Stress fractures, tendinitis, medial tibial stress syndrome are all examples of maladies referred to as shin splints. However, one commonly missed diagnosis often confused with shin splints is exertional compartment syndrome (ECS). Exertional compartment syndrome (ECS), also known as exertional induced compartment syndrome or chronic compartment syndrome is a unique condition where an athlete experiences muscle pain in the legs with weakness of the ankle as a result of increased muscle pressure in one or all four compartments of the leg. Patients with this condition will typically note the onset of symptoms at a fix point ranging from 5-30 minutes into an activity and at a specific level of intensity, and the symptoms usually occur in both legs. The most characteristic feature of (ECS) is that it is exercise induced and never present at rest. The vast majority of patients with ECS are runners who range from the occasional jogger to the elite Olympic level runner. It is not unusual to see unconditioned athletes develop these symptoms after beginning an exercise program. Occasionally the problem is recognized in high-level cyclists as well.
Why does this happen?
There are generally 4 compartments in the leg, each is surrounded by tight tissue resembling a thick saran wrap which holds the compartment in place and separates it from the adjacent compartments. Patients with ECS will complain of cramping, burning, tightness and weakness of the ankle with exercise. Some will also develop numbness in the foot and describe a foot slap due to ankle weakness during running. This may cause the runner to trip as a result of the foot not being able to clear the ground just before landing. Pain will force the athlete to stop at which time symptoms completely resolve after resting a few minutes. The symptoms are reproducible with exertion and should be recreated in the office setting with an exercise challenge such as running on a treadmill or stair climbing. Specific muscle and sensory testing after exertion will aid in confirming the diagnosis and specifying the compartment affected. During strenuous activity blood flow increases to the leg causing the volume and weight of the muscle to increase by about 20%. As a result, the muscle fibers attempt to swell but are restricted by the tight surrounding fascia. Immediately after activity the leg may feel tense or tender with deep message or passive stretch. Runners may find that a bubble or several bubbles are visible in the front of the leg which we refer to as fascial hernias. These are areas where the fascia may have become weak allowing the muscle to herniate through due to the excessive internal leg pressure. The physical exam during rest is otherwise generally unremarkable. X-rays, magnetic resonance imaging, vascular studies and other imaging exams are used to rule out other diagnosis but are not helpful, as they are always normal in ECS. To confirm the diagnosis the sports physician will need to measure the pressure in each compartment of the leg with a special instrument much like a tire gauge. In normal patients the pressure difference between rest and activity is small, while those with ECS will have a dramatic increase in pressure readings after activity.
ECS is not an emergency
Exercised-induced compartment syndrome is not to be confused with acute compartment syndrome which is considered a surgical emergency. Typically, acute compartment syndrome is a result of a traumatic injury causing a similar increase in compartment pressures due to hemorrhaging. In this situation the pressure cannot be controlled easily and the delay in treatment may cause permanent muscle and nerve damage. In contrast people with exercise induced compartment syndrome will find that the pressure is relieved completely with rest. ECS is generally not considered an emergency.
What is the treatment?
A period of rest and avoiding high intensity activities can be tried. Often more experienced athletes will recognize the level of intensity provoking symptoms and attempt to exercise just below that threshold. Muscle retraining by running more efficiently may also improve symptoms.
However, if the diagnosis of ECS is clear and the symptoms persist despite exhausting conservative treatment, surgery may be required if the athlete intends to continue the sport. The surgery involves releasing or cutting the tight fascia using a technique called fasciotomy. This allows the muscle to expand during exercise. Complication rates are rare when done by experienced surgeons and may include bleeding, wound breakdown, and numbness. Also, recurrence of symptoms can redevelop several years after a fasciotomy in a small percentage of patients as a result of the fascia reforming. The results of the procedure however are generally very gratifying and has allowed many athletes to remain active in their sport.