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
Essential Pointers On Testing For ECS
It has been fairly well established that the most reliable method for diagnosing ECS is by taking intramuscular compartmental pressures. Currently, I use the Stryker intracompartmental pressure monitor system.4
When the athlete/patient comes in, I test the one leg, prep it with povidine-iodine swabs and mark the areas for injection. The athlete should be in supine position on the exam table, with his or her knees bent so the sole of the foot is flat on the table. By having the lower leg upright, I have access to all the compartments.
For the anterior compartment, the injection site is midway up the leg, staying close to the lateral aspect of the tibia and directly over the anterior tibial muscle. Mark the area and anesthetize the skin superficially with 2% lidocaine plain.
Be sure to zero balance the pressure monitor system, holding the unit approximately perpendicular to the muscle and parallel to the exam table. Insert the side-ported needle into the anterior tibial muscle approximately one inch deep and inject the saline from the syringe into the muscle belly. (As far as the saline goes, I usually inject .3cc until the patient says the injected site feels “full.”) Then record the back pressure and read off the monitor once you’ve reached an equilibrium state, which occurs when the LCD readout stops or fluctuates back and forth a few degrees mmHg.
Reload the syringe with saline and repeat the procedure for the lateral compartment, which you would measure midway up the leg and just lateral to the surface of the palpated fibula bone. Here, you’re gauging the pressure within the peroneal muscles. For the deep posterior compartment, measure it midway up the leg, staying close to the medial surface of the tibia. Insert the needle just medial and posterior, staying relatively superficial within the posterior tibial muscle belly.
Finally, measure the superficial posterior compartment, which is slightly further up on the leg. Insert the needle into the medial or lateral head of the gastrocnemius, depending on which side was more symptomatic.
The superficial posterior compartment is the least common of the compartment syndromes and testing is often not necessary. You’ll find the anterior compartment is the most commonly involved and is often present with lateral compartment syndrome.
What Comparison Pressure Readings Will Tell You
Once you record the pressures, ask the patient to run either on a treadmill or outside until he or she feels the symptoms. Immediately repeat the testing. Do another test five minutes after the post-exercise test.
Normal baseline pressures pre-exercise should be approximately 15 to 20 mmHg. If the post-exercise pressures increase greater than 30 to 45 mmHg, this is considered pathologic. However, I have noted that most patients with ECS have elevated pressures above 45 mmHg during the immediate post-exercise testing. I should also point out that many patients have had a baseline compartment pressure reading greater than 30 mmHg, which is highly suggestive of ECS. Also keep in mind that if the immediate post-exercise measurements are significantly greater than 45 mmHg., you may not have to do the final five-minute post-exercise testing.