The deep posterior compartment is a surrounded by a sheath which contains the muscles of the lower leg. Compartment syndromes arise when a muscle becomes too big for the sheath that surrounds it.
Posterior compartment syndrome may also be known as posterior shin splints and can be acute or chronic. An acute injury will be from an impact or contusion resulting in pain and restricted movement of the ankle. A chronic compartment syndrome will cause deep aching pain in the lower leg which comes on during a run, goes away with rest only to return when training resumes. There may also be a pain when pulling the foot and toes downwards against resistance. Sometimes a foot drop is seen with significant weakness in lifting the foot when walking.
An acute compartment syndrome is caused by impact or trauma which causes bleeding within the muscle compartment. The swelling increases pressure inside the compartment resulting in pain. A muscle strain can also bleed within a muscle compartment having the same effect.
A chronic compartment syndrome usually comes on over a longer period of time through overuse. The muscle grows too big for the compartment or sheath that surrounds it increasing pressure within the compartment and causing pain.
Biomechanical factors such as over pronation where the foot rolls in or flattens too much when running can abnormally increase the load on certain muscles making a compartment syndrome more likely.
Immediate medical attention should be sought for a severe acute compartment syndrome as long-term damage to nerves and muscles can occur. A doctor may prescribe anti-inflammatory medication e.g. ibuprofen to help reduce pain and swelling and in more severe cases surgery may be indicated. Always check with a doctor before taking medication.
Rest, but try to exercise your upper body or cycle if it is not painful. Apply ice or cold therapy for 20 minutes at a time. Use a wet tea towel or commercially available cold packs to avoid skin burns.
A chronic compartment syndrome may respond to cross friction massage techniques which aim to stretch the sheath creating more space for the muscle.
A full gait analysis can be done to analyze running style and any biomechanical dysfunction of the foot can be corrected with orthotic inserts. These are placed into the shoes and correct the motion of the foot which in turn will reduce the load on certain muscles in the lower leg.