|
 |
| |
Compartment Syndrome
As the sporting season begins again, here is an article that may be relevant to many -- especially for those who have done too much, too soon.
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 attached 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, the most common site is the lower leg. There are 2 forms -- acute and chronic. Chronic compartment syndrome is often overlooked as a possible cause of muscle pain, and the acute syndrome can cause serious and permanent damage if not treated rapidly.
Chronic syndrome
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 also often be swelling and abnormal sensations in the affected limb during and immediately after exercise.
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, the condition is not exclusive to the lower leg. You may come across compartment syndrome in the arm in a weightlifter, sport climber or motorcyclist, in these instances the flexor 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 with stretching and active contraction. The athlete may also complain of pins and needles or numbness. In general, symptoms will disappear within an hour of stopping the activity but recur when exercise resumes.
Thus the clinical features of CECS are only evident immediately after exercise, and the nature and location of the 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 CECS or what predisposes individuals to it. During exercise muscle bulk increases by up to one-fifth and it may be this expansion, plus repeated muscle contraction, that increases the intra-compartmental pressure to a level that causes transient ischaemia (a temporary decrease in blood flow) and deoxygenation.
An alternative explanation is that muscle tissue, damaged by repetitive hard surface exercise, provokes swelling and therefore decreases blood flow within the compartment.
Treatment in the first instance is a change of exercise regimen or complete rest, especially if the diagnosis is made early. Unfortunately CECS is rarely diagnosed early and each successive episode of inflammation and irritation will cause the compartment fascia to become less and less yielding. There have been several reports of successful conservative treatment of massage and physiotherapy, but if they do not work alone then fasciotomy (surgical incision to the fascia) is the treatment of choice.
Acute syndrome
The basic nature of acute compartment syndrome (ACS) is the same as CECS: increased tissue pressure within a muscle compartment compromises the blood supply and the function of the 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 result of any trauma to a muscle compartment or indeed an adjacent compartment. ACS is limb-threatening and should be treated as an emergency.
Although 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 75% of cases. Comminuted (multi-fragment) fractures are more likely to give rise to ACS, probably reflecting the greater degree of force required to cause this type of injury. Indeed any high-energy trauma is more likely to cause 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 (decreased blood flow) well, but by six hours repair is uncertain and after eight hours, damage is irreversible.
Acute compartment syndrome has been very occasionally recorded in patients with no history of trauma.
Summary
Acute and chronic compartment syndromes may have linked pathophysiology but occur in very different clinical settings. 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 ACS.
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.
Justin Faulkner
BSc (Hons) U.K., M.C.S.P., M.H.K.P.A.
Physiotherapist / Director
Physiocentral
Suite 1203, 12 Floor
The Centrium
60 Wyndham Street
Central
Hong Kong
T: +852 2801 4801
|
|
|
