The muscles in our limbs are split into sections or ‘compartments’ bound by strong and relatively unyielding membranes of fibrous tissue (deep fascia), which also attach to bone, in effect wrapping up the different muscle groups. Every compartment has a blood and nerve supply.
Compartment syndrome arises when the pressure inside this enclosed space increases to the point where it interferes with the blood supply to the structures. A cascade of injury follows, with disruption to the metabolic processes of the muscle, cell death and leakage of fluid from capillaries, which further increases the excessive pressure.
Although legs, feet and arms can all be affected by compartment syndrome, with sports-people you are most likely to come across it in the lower leg. There are two forms, acute and chronic, and the sports therapy professional needs to be aware of both. Chronic compartment syndrome is often overlooked as a possible cause of muscle pain; and acute compartment syndrome can cause serious and permanent damage if it is not treated rapidly.
Going under the name of chronic exertional compartment syndrome (CECS), this overuse condition mainly affects active, athletic people. It is characterised by muscle pain that repeatedly occurs with vigorous exercise and subsides with rest. The pain gradually worsens as exercise continues, ultimately restricting performance. There will often also be swelling and abnormal sensations in the affected limb during and immediately after exercise.
Chronic exertional compartment syndrome (CECS) can affect athletes of any age, including adolescents. Anyone whose sport involves a lot of running or jumping, or indeed long-distance walking, may be at risk. It usually occurs in the lower limb, where there are four tightly packed muscle compartments. Of these it is most commonly the anterior compartment containing the tibialis anterior muscle, that succumbs. The thigh and foot are also vulnerable.
However compartment syndrome is not exclusive to the lower leg. You may come across compartment syndrome in an arm in a weightlifter(1), sport climber(2) or motorcyclist(3); in these instances the flexor forearm compartment is usually involved.
Muscle weakness of the affected limb may be a feature of these episodes and gradually increasing fullness (literally denseness, crowding or swelling) is a frequent complaint. Pain increases both on passive stretching and active contraction. The athlete may also complain of paraesthesia (pins and needles). In general symptoms disappear within an hour of stopping the activity but recur when exercise resumes.
Thus the clinical features of chronic exertional compartment syndrome (CECS) are only evident immediately after exercise, and the nature and location of signs and symptoms will depend on the compartment affected.
As with any compartment syndrome, symptoms are the result of the structures within a closed myofascial compartment being compressed by increased pressure; but beyond this we don’t really know what causes Chronic exertional compartment syndrome (CECS), or what predisposes individuals to it. During exercise, muscle bulk increases by up to a fifth and it may be this expansion, plus repeated muscle contraction, that increases the intracompartmental pressure to a level which causes transient ischaemia and deoxygenation(4,5).
An alternative explanation is that muscle tissue, damaged by repetitive hard surface exercise, releases protein-bound ions which increase cell leakage, provoke oedema and so decrease blood flow within the compartment.
|Compartment||Major nerve supply||Muscles involved|
|Anterior||Deep peroneal||Tibialis anterior
Extensor hallucis longus
Extensor digitorum longus
|Lateral||Superficial peroneal||Peroneal longus, brevis, tertius|
|Deep posterior||Posterior tibial||Tibialis posterior, long flexors, soleus|
|Superficial posterior||Sural||Gastrocnemius complex|
Physical examination at rest often provides little helpful information: you are unlikely to see any abnormalities unless examining immediately postexercise. It is vital to take a careful history, including training regimes. You will need to establish the specifics of the pattern of pain: how long after the start of exercise and at what intensity it sets in; how and when it eases off again.
Passive stretching of the involved muscle after exercise may increase your client’s pain. Over time you may notice muscle atrophy, and the client may report tenderness and increased tension in the involved compartment. But be careful with differential diagnosis: tenderness directly over the tibia is more likely to be a stress fracture, tibialis posterior tendinitis or periostitis.
One further rare condition can present with almost identical symptoms as chronic exertional compartment syndrome (CECS) and must be excluded: popliteal artery entrapment syndrome (PAES). This most frequently affects young male athletes who describe exertional calf pain with possible associated leg weakness and paraesthesia. PAES is the partial or complete occlusion of the popliteal artery in the popliteal fossa (back of the knee), secondary to aberrant anatomy. Weaker distal pulses and poor capillary refill of the extremity with exercise or with provocative manoeuvres (repeated ankle dorsiflexion with knee extension) and normal compartment pressures help differentiate PAES from chronic exertional compartment syndrome (CECS). Angiogram provides definitive evidence.
Coupled with a careful history, the gold standard for chronic exertional compartment syndrome (CECS) diagnosis is to measure the pressure within the affected compartment, first at rest, then at several points while exercising, and finally 5, 10 and 20 minutes after exercise. It is very important that symptoms are elicited during this process and measurements taken at intervals until the symptoms subside. This is usually an outpatient procedure, requiring the insertion of a pressure probe into the affected compartment.
Several non-invasive forms of investigation have been assessed for reliability of diagnosis, including MRI, tomographic imaging and spectroscopy, but all have been shown to have inadequacies.
In the first instance a change of training regimes or complete rest may resolve the symptoms, especially if the diagnosis is made early.
Chronic exertional compartment syndrome (CECS) is usually not identified early, and each successive episode of inflammation and irritation will cause the compartment fascia to thicken and become fibrotic, making it increasingly unlikely to be able to return to its normal state of yield, even with rest. Although there have been reports of successful conservative treatment, massage and physiotherapy alone are rarely satisfactory. Fasciotomy (surgical incision of the fascia) is the treatment of choice.
After surgery 70-85% of patients are able to return to pre-treatment levels of activity, symptom-free. Patients with Chronic exertional compartment syndrome (CECS) in the deep posterior compartment respond less well than those whose anterior or lateral compartment is involved(6).
These may be amenable to further surgery but this may not alter muscle strength. Cases of recurrent Chronic exertional compartment syndrome (CECS) are almost certainly attributable to scarring and closure of the initial compartment release.
The basic nature of acute compartment syndrome (ACS) is the same as Chronic exertional compartment syndrome (CECS): increased tissue pressure within a muscle compartment compromises the blood supply and the function of structures within that space. However, it differs from CECS in that it does not require exertion of the muscles to incite pain; and the pain does not subside until treated. It can occur as a complication of any trauma to a muscle compartment or indeed an adjacent compartment. Acute compartment syndrome (ACS) is limb threatening and should be treated as an emergency.
Although acute compartment syndrome (ACS) can affect any limb or muscle compartment, including the abdomen, it mainly occurs after trauma to the lower leg. Fractures – most commonly of the tibia – are the cause in three-quarters of cases. Comminuted (multi-fragment) fractures are more likely to give rise to acute compartment syndrome (ACS), probably reflecting the greater degree of force required to cause this type of injury. Indeed any high energy trauma is more liable to cause acute compartment syndrome (ACS), and penetrating injuries such as gunshot wounds often cause severe muscle laceration and arterial tears, which in turn lead to increased intracompartmental pressure.
Muscles tolerate four hours of ischaemia well, but by six hours repair is uncertain and after eight hours, damage is irreversible(7).
Acute compartment syndrome has very occasionally been recorded in patients with no history of trauma(8).
The patient will experience severe pain, out of keeping with the injury sustained and unrelieved by opiate analgesia.
Early signs and symptoms include this disproportionate level of pain, which can be aggravated by passive muscle stretching; palpable tightness and tenderness of the area; and sensory deficit in the distribution of any sensory nerve traversing the involved compartment. Late symptoms include paraesthesia, muscle weakness and loss of distal pulses. Diagnosis will be confirmed by measuring compartment pressure, and will lead to fasciotomy.
If you suspect acute compartment syndrome (ACS) in your patient, try to:
If a plaster cast has been applied, this should be split immediately: a split on one side can instantly relieve compartmental pressure by 30% and the removal of cast and padding will bring pressure down by 85-90%(9).
Fasciotomy is the definitive and only treatment for acute compartment syndrome (ACS). Morbidity from delay is significant, so the operation should be performed immediately. The wound should not be stitched until a post-surgical assessment has been done at 48 hours, and subsequent skin grafts may be needed for successful healing.
Acute and chronic compartment syndromes may have linked pathophysiology but occur in very different clinical settings. Chronic exertional compartment syndrome (CECS) is a condition most commonly affecting the lower extremities in competitive athletes, probably caused by raised pressure within a non-compliant muscle compartment due to repetitive muscle activity causing symptoms during and immediately after exercise. Diagnosis is more complicated but less urgent than acute compartment syndrome (ACS).
Acute compartment syndrome (ACS) is usually, but not exclusively, associated with a fracture. It is a serious limb-threatening condition and delay in treatment may lead to infection, complications and even limb amputation.