Chronic Exertional Compartment Syndrome (CECS) of the Forearm
Arm pump is a clinical condition in which an individual develops intermittent marked pain in the forearms after a period of exercise or exertion. The pain is thought to arise due to swelling of the muscles of the forearm that affects the blood flow to these muscle and causes the oxygen levels to drop.
Arm pump typically affects younger adults, mainly men. It is most commonly associated with motor sports such as motocross and road racing, but other activities such as paddling, weight lifting and mountaineering can induce this condition. It is thought that riders participating in motocross and road racing are particularly affected due to the combination of vibration, forced grip and repeated wrist movements to control the throttle. The symptoms typically start approximately 7 minutes in to the race.
How do I know if I have it?
This is not a common condition but it should be considered in an individual who develops marked forearm pain after a period of exertion that settles spontaneously after a period of rest (ranging from 12 minutes to 24 hours). The forearm will typically feel hard and tight while the pain is present. Numbness in the hand, or cramping of the muscles of the forearm, weakness or clumsiness may occur.
How is the diagnosis made?
To make the diagnosis your doctor will ask you questions and will perform special tests. Often the clinical examination will be normal. Your doctor will usually refer you to a specialist surgeon for investigation when the diagnosis is suspected. The specialist may recommend serial MRI scans of the arms at rest, immediately after exercise and every five minutes for a period of 15 minutes but this is quite an expensive investigation. MRI scan may help to exclude other causes of forearm pain (see below). The condition can be diagnosed by direct measurement of the pressure within the muscles. This can only be done by passing a needle through the skin into the muscle under local anaesthetic and connecting this needle to a pressure device. This is an invasive procedure and should only be performed by a specialist. The diagnosis is said to be supported if the pressures are >10mmHg at rest and >20mmHg 1 and 5 minutes after exertion. The speed that the pressure returns to baseline after exertion may be a more reliable diagnostic determinant. An increase in the circumference of the forearm on exertion may also be found.
How is the condition treated?
Attempts at symptom control by activity modification and rest should be tried first but are not always successful. Arm pump can be treated by surgery to release the fascia (connective tissue covering) of the muscle. This is usually done under a general anaesthetic and the tissue can either be split or removed. The outcomes of these two procedures are thought to be the same. Where the diagnosis is correct successful outcome can be expected in the majority of patients (80-90%). Patient satisfaction has been reported to be very high following this procedure.
What happens after the operation?
After surgical fasciectomy/fasciotomy the patient must rest the arm. The arm is bandaged but a splint is not required. The wound must be kept dry for 10 days. Active mobilisation exercises are undertaken. Most individuals can return to their sport/occupation at four to six weeks after surgery. Performance may be improved after surgery for some individuals.
What other conditions have similar symptoms?
Tendinopathies (such as tennis or golfers elbow) of the forearm muscles, blood vessel or nerve entrapment may present with similar symptoms and should be excluded.
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