Compartment syndrome arises when a muscle becomes excessively swollen, exceeding the capacity of the surrounding sheath. It can manifest as either acute (sudden onset) or chronic (gradual onset).
Symptoms
An acute compartment syndrome can result from direct trauma or impact, causing the following symptoms:
- Pain in the lower leg, specifically in the calf muscle area or on the inside of the shin.
- Restricted movement at the ankle may be experienced.
- Immediate medical attention is crucial if acute compartment syndrome is suspected.
- Particularly, if the pain worsens gradually, it can lead to long-term or permanent leg injury.
In a chronic compartment syndrome, also known as deep posterior compartment syndrome, the following features are observed:
- Pain in the lower leg, specifically located over the inside of the tibia (shin bone).
- Similar symptoms to medial tibial stress syndrome (shin splints) or persistent calf pain.
- Deep aching pain in the lower leg characterizes chronic posterior compartment syndrome.
- Pain typically occurs during running and subsides with rest, but reappears upon resuming training.
- Patients often report a sensation of tightness or pressure.
- When you exert downward pressure on the foot and toes (plantar flexion) against resistance, like going up onto your toes, you may also experience pain.
Other signs
Numbness or pins and needles, as well as lumps and bumps along the inner shin, may indicate muscle protrusion through its surrounding sheath. Tenderness along the inner shin may be present, albeit less severe than in medial tibial stress syndrome due to the deeper compartment.
Diagnosis & compartment pressure tests
To accurately diagnose chronic compartment syndrome, your doctor or physiotherapist will conduct compartment pressure tests for all lower leg compartments. If they suspect this condition, they will perform pressure tests both before and after exercise.
The procedure involves inserting a needle (Stryker catheter) into the affected muscle compartment. It is crucial for the patient to exercise sufficiently to provoke their symptoms. The compartment pressure is then tested immediately after exercise to ensure the validity of the results.
Approximately 10 minutes later, when the symptoms have subsided, your doctor will repeat the test.
What is normal compartment pressure?
Normal compartment pressures range from 0 to 10 mmHg. Chronic compartment syndrome can be identified by one of the following indicators:
- Maximum pressure exceeding 25 mmHg during exercise.
- An increase in pressure of more than 10 mmHg.
- Resting post-exercise pressure exceeding 25 mmHg.
Ideally, the pressure should return to normal levels within 5 minutes.
Deep posterior compartment syndrome often coexists with other causes of shin pain, which can lead to misdiagnosis or confusion. Some potential conditions to consider are medial tibial stress syndrome, popliteal artery entrapment syndrome, vascular claudication, and stress fractures.
What is posterior compartment syndrome?
The posterior deep compartment of the lower leg houses the flexor hallucis longus, flexor digitorum longus, and tibialis posterior muscles, enclosed by a sheath. In some individuals, there may be an additional sheath surrounding the tibialis posterior muscle.
Acute Compartment Syndrome:
Impact or trauma triggers acute compartment syndrome, leading to bleeding within the muscle compartment. Swelling occurs, increasing pressure and causing pain. Muscle strains can also lead to bleeding within a muscle compartment, causing similar effects.
Chronic Compartment Syndrome:
Chronic compartment syndrome develops gradually due to overuse. The muscle surpasses the capacity of the surrounding compartment or sheath, elevating pressure within the compartment and causing pain. Biomechanical factors, such as overpronation (excessive inward rolling or flattening of the foot during running), can abnormally strain certain muscles, increasing the risk of developing compartment syndrome.
Treatment for posterior compartment syndrome
Acute and Chronic Compartment Syndrome:
Acute: Caused by impact or trauma, acute compartment syndrome results in bleeding within the muscle compartment. Swelling occurs, increasing pressure and causing pain. Muscle strains can also lead to bleeding within a muscle compartment, producing similar effects.
Chronic: Developing gradually due to overuse, chronic compartment syndrome occurs when the muscle outgrows the surrounding compartment or sheath. This elevates pressure within the compartment, causing pain. Biomechanical factors like overpronation during running can excessively strain certain muscles, increasing the likelihood of developing compartment syndrome.
Massage
Massage Techniques: Massage techniques can be beneficial for chronic compartment syndrome by stretching the sheath and creating more space for the muscle. Cross-friction massage and myofascial release techniques involve working the muscle along its length while the foot undergoes dorsiflexion (lifting the foot and toes upwards). This should be performed both passively (by the therapist) and actively (by the patient). The goal is to stretch and reduce the thickness of the myofascial sheath.
Acupuncture (Dry Needling): Acupuncture, also known as dry needling, may help alleviate symptoms of chronic compartment syndrome.
Gait analysis
You can undergo a full gait analysis to scrutinize your running style and pinpoint any biomechanical problems. Specifically, it will identify issues such as overpronation, where the foot rolls inward or flattens. This abnormal motion can stress the lower leg muscles, promoting muscle growth (hypertrophy) and potentially leading to chronic compartment syndrome.
To correct overpronation, you can use orthotic inserts that adjust the motion of the foot. You place these inserts inside your shoes, and they work to alleviate the strain on certain lower leg muscles.
Surgery for posterior compartment syndrome
Surgical Intervention for Compartment Syndrome:
If conservative treatments fail, surgery may be necessary to alleviate muscle pressure. The procedure involves making one or two small incisions and cutting the sheath along its length. Surgeons must exercise caution not to damage the nearby Saphenous vein to prevent post-surgery complications such as swelling or cellulitis.
If the initial procedure doesn’t yield the expected results, some surgeons may opt to partially remove the sheath during a second operation to prevent its reformation during healing. However, they use this approach judiciously because it carries a risk of extra complications. The surgeon also factors in the pressures in other compartments of the lower leg before making such a decision.
