Compartment syndrome is characterized by pain that develops due to the build-up of pressure within muscles. The pressure within muscles is high enough to compromise the blood and nerve supply to the muscles causing ischemia that results in pain.

The condition can be acute or chronic. The former is a medical emergency and, if overlooked, can cause permanent muscle damage. The latter is usually due to fatigue and exhaustion resulting from exertion.

Compartment syndrome may affect the arm, hand, thigh, abdomen, buttocks, leg, and foot.

Compartment syndrome of the lower leg affects the non-extensible muscular compartments.

For example, the anterior compartment syndrome results in pain along the front of the lower leg. The aching, tight, cramping, or squeezing pain occurs during exercise and resolves cessation of exercise. The anterior compartment syndrome may also be associated with weakness of the leg and numbness between the big and second toes.  

Anatomy

Compartments in the legs and arms are formed by groupings of muscles, nerves, and blood vessels. The compartment constituents are enclosed in a tough membrane called fascia. This fascia is non-extensible as it acts to keep the compartment elements in place.

Swelling or bleeding due to any reason gives rise to compartment syndrome. As the fascia does not stretch, the accumulation of fluid and blood increases the pressure within, further compromising the blood and nerve supply. Without ample nutrient supply, the muscle tissue undergoes necrosis and death if not timely addressed.

The lower leg has four compartments;

• anterior
• lateral 
• deep posterior
• superficial posterior

The borders of the compartment in the lower leg are made by;

• bones of the lower leg (tibia and fibula)
• the interosseous membrane 
• the anterior intermuscular septum

The anterior compartment includes;

• Tibialis anterior
• Extensor hallucis longus
• Extensor digitorum longus
• Peroneus tertius
• Deep peroneal nerve

The lateral compartment includes;

• peroneus longus and brevis
• superficial peroneal nerve

The deep posterior compartment includes;

• tibialis posterior
• flexor hallucis longus
• flexor digitorum longus
• popliteus
• tibialis nerve

The superficial posterior compartment includes;

• gastrocnemius
• soleus
• plantaris
• sural nerve

Anterior compartment syndrome is the most common of all.

The anterior compartment of the leg contains muscles that produce dorsiflexion, inversion, and eversion of the foot. Alongside muscles, vessels as the anterior tibial artery and veins and nerves like the deep fibular nerve are also present.

Causes of compartment pain syndrome

Compartment syndrome is of three types depending upon their causative factors;

• acute
• subacute
• chronic exertional

Acute compartment syndrome (ACS) is caused by bleeding or edema.  Among the most common causes of this complication are

• fractures
• blunt trauma or soft tissue damage
• re-perfusion injury after acute arterial obstruction
• car accidents and crush injuries
• severe bruising of the muscle in a compartment
• anabolic steroid use
• constricting bandages like casts

Chronic compartment syndrome (CCS) is common in young athletes like long-distance runners, football players, basketball players, and military men and women. The condition develops after strenuous exercise done over a regular period. 

The average mean interstitial tissue pressure in relaxed muscles is approximately 10-12 mmHg. Pressure exceeding 30 mmHg or more causes compression of the small vessels in the tissue, which leads to a vicious cycle of reduced nutrient blood flow, ischemia and pain.

Signs and Symptoms of compartment syndrome

Acute Compartment Syndrome presents as;

• Pain on stretching the muscle present in that compartment
• Tingling or burning sensations (paresthesia) in the skin due to nerve compression
• A feeling of tightness or fullness in the muscle
• Swelling of the affected area
• Late signs indicating permanent damage include numbness or muscle paralysis.

Chronic (Exertional) Compartment Syndrome presents itself as;

• Pain or cramping during exercise that subsides on stopping the activity
• Numbness
• Difficulty moving the foot
• Apparent muscle bulging

Compartment syndrome of the lower leg results in lingering signs and symptoms even after recovery as reduced muscular strength, reduced range of motion, and pain. The pain is usually located over the area of the affected compartment. It may radiate to the ankle or foot.

Paralysis of muscles specific to the affected compartment is a late sign.

Diagnosis of compartment syndrome

In case of suspected compartment syndrome, the patient is taken to the emergency where the pressure in the muscle is checked and analyzed for appropriate treatment. Persistently high pressure after exercise is a sign of chronic compartment syndrome.

Physical examination and x-rays help rule out other pain-causing conditions of the lower leg, for example, stress fractured tibia, medial tibial pain syndrome, nerve entrapment syndromes, vascular claudication, etc.

The clinical presentation of acute compartment syndrome is;

• Finding of swelling in the affected area
• The inability to actively move flexors and extensors of the foot
• Pain with passive stretching of the affected muscles shows the progression of the condition
• Disturbed sensation in the webspace between the first and second toes

Chronic exertional compartment syndrome has the following findings;

• Pain within first half an hour of exercise and may radiate to ankle or foot
• Pain resolves with stopping exercise
• Daily activities usually do not cause pain
• Swelling of the affected extremity is evident on examination
• Inability to actively move flexors and extensors of the foot
• Firm wooden feeling in the affected area

MRI remains a noninvasive alternative to detecting elevated compartment tissue pressures in all cases.

Treatment of compartment syndrome

Acute Compartment Syndrome is always treated as a surgical emergency. A fasciotomy procedure involves making a skin incision and releasing the skin and fascia around the muscle. The skin incisions may be repaired with a skin graft because of the swelling present.

Chronic (Exertional) Compartment Syndrome is managed with conservative therapy.

1. During the acute phase

1. RICER

Rest, ice application, elevation are advised, but any casting, splinting, or compression of the affected limb is not recommended for chronic compartment syndrome.

• Medication
• TENS

• After the initial symptoms have subsided

• Massage
• Therapeutic ultrasound
• Active rehabilitation

Cessation of triggering activities is the only option for chronic compartment syndrome. Modification of activities and exercise is advised for athletes. Regular physical activities should be modified, pain allowing. Patients with the chronic syndrome may need surgical intervention some time in their lives.

Conservative options for physical therapy include a decrease in activity or load to the affected compartment. Water exercises help maintain mobility and strength without excessive loading of the affected muscles. Massage and stretching exercises also benefit to some extent.

Pre-surgical therapy in chronic cases includes reduction of activity and cross-training, and muscle stretching before initiating exercise. Shoe modification and the use of nonsteroidal anti-inflammatory medications (NSAIDs) to reduce inflammation are advised before surgery for chronic cases.

Post-surgical physical therapy includes early mobilization and assisted weight-bearing exercises.

Upgradation of activity to stationary cycling and swimming is suggested after healing the surgical wounds.

Isokinetic muscle strengthening exercises are initiated at 3-4 weeks.

Running may also be incorporated at three to six weeks, followed by full activity between six to twelve weeks.

Anterior compartment syndrome is managed with;

• Orthotics
• Taping
• Hydrotherapy
• Postural realignment

Some rehab exercises for compartment syndrome include;

Stretch for deep posterior compartment

• Lean against a wall with both hands supporting your body.
• Keep your healthy leg straight.
• Lunge forward with the unaffected leg. You should feel a stretch in the calf muscles.  
• Hold for half a minute.
• Performing twelve reps at least once to twice a day.

Neural glide for tibial nerve

• Lie down on the floor.
• Keep your healthy leg straight and extended.
• Lift your affected leg in a straight raise.
• Supporting the back of the thigh by holding it with your hands.
• Move your knee in flexion and extension.
• Try to point the toes in plantar flexion when the knee is fully extended.
• Repeat twelve times.

Mobilization of the fascia

• Sit with the affected knee flexed.
• For this exercise, palpate on the leg's medial (inner) side just posterior to the tibia.
• Place a golf ball in the palpated area.
• Place another ball directly opposite on the backside of the leg.
• Slowly apply pressure on the medial side of the leg. Make sure to flex or scrunch the toes while applying pressure.
• Hold the pressure.
• Move the balls along the tibia, holding and keeping the pressure at each spot for few seconds.

Prevention of compartment syndrome

• Wear appropriate footwear designed explicitly for a terrain
• Choose appropriate surfaces and ground for exercise
• Pacing your activities with periods of breaks
• Quitting certain activities altogether
• Modifying physical activity to lower the risk of injury