What is Tibial Anterior Compartment Syndrome?
Compartment syndrome is a condition that arises when pressure builds up within a certain area of the body, known as a compartment. This pressure becomes so high that it cuts off the blood flow from the arteries, leading to a lack of oxygen, which can hurt the muscles and nerves in that area. This may happen due to an injury or overusing a muscle. In the leg, it can happen in any of the four distinct areas: the front, the side, the top back part, or the deep back part. However, this syndrome can also occur in other body parts, including the thigh, forearm, hand, and wrist.
Let’s take a look at one of these compartments: the front part of the leg. Its muscles include the tibialis anterior, extensor digitorum longus, extensor hallucis longus, and fibularis tertius. Generally, these muscles are responsible for lifting up your foot (dorsiflexion) and rolling your foot to the side (eversion and inversion). To be more specific, the tibialis anterior lifts up and turns in your foot. The extensor digitorum longus extends your four smaller toes and also helps in lifting up your ankle, while the extensor hallucis longus helps extend your big toe and lift your ankle. The fibularis tertius also helps lift up and roll out your foot.
The front part of the leg gets its nerve supply from the deep fibular nerve, that comes off from a larger nerve called the common fibular nerve. It gets its blood supply from the anterior tibial artery, which comes off from a large artery behind the knee and continues into the foot as the dorsalis pedis artery. This area of the leg is encased by the front part of the tibia bone, the front inner part of the fibula bone, a tough piece of tissue between the two bones (interosseous membrane), and a sheet of tissue separating muscles on the front side of the leg.
What Causes Tibial Anterior Compartment Syndrome?
Compartment syndrome, a painful and potentially serious condition, often happens because of an injury. This condition can have many different causes. It might come from a direct blow or wound, a bone fracture, bleeding, or even burns. Other causes can be infections like tetanus or myositis, neurologic conditions such as seizures, toxicological issues like venomous bites or substance abuse, and conditions affecting the kidneys. Abuse of androgenic steroids, decreased amount of certain substances in the blood (serum osmolarity), and muscle-tearing from activities or excessive exercise can also lead to it.
Sometimes, compartment syndrome can even be caused by autoimmune disease like vasculitis, blood clotting in deep veins, heavy bleeding, or muscle injury (rhabdomyolysis). It might also occur as a side effect of another disease (a sequela) like swelling post-ischemic.
Medical treatment or routine care can sometimes inadvertently cause compartment syndrome. This might happen if a dressing, splint, or cast is too tight or if a patient is positioned incorrectly during a procedure. Malfunctioning pressure devices used in medical procedures or treatments that get injected directly into the muscle or bone can also result in compartment syndrome. It can also occur from bleeding during attempts to insert a needle into a vein or artery or due to certain types of high-pressure irrigation used during surgery. Even clothing used in the military to prevent shock can cause this condition.
Lastly, after surgery, especially orthopedic procedures, there’s a risk of developing compartment syndrome. This may be due to post-surgical bleeding, swelling of muscle (edema), or if the layers of tissue surrounding the muscles (the fascia) are stitched too tightly.
Risk Factors and Frequency for Tibial Anterior Compartment Syndrome
Tibial fractures, also known as shinbone fractures, are the main reason for a condition called compartment syndrome, making up 12% of all such cases. An open fracture, where the bone breaks through the skin, is more likely to lead to this condition (6% of cases) than a closed fracture (1.2% of cases) where the bone doesn’t break the skin. Younger people with these fractures have a higher risk of developing compartment syndrome. The risk also increases if the fracture is long compared to the tibia’s length, or if it’s a specific kind of fracture known as Schatzker VI. The risk is also higher if the fibula, the smaller bone in the lower leg, is also broken.
Men may be more commonly affected by traumatic compartment syndrome, a version of the syndrome caused by severe injury. However, whether or not an inner bone rod is used doesn’t affect the likelihood of developing the condition. When vascular insult, or damage to the blood supply, is involved, the syndrome is much more common, with one study reporting that 19% of patients with such injuries needed a surgical procedure called a fasciotomy.
Chronic exertional compartment syndrome is a frequent cause of leg pain in athletes, accounting for 27% to 33% of cases. Being a runner and having defects in the fascia, the layer of tissue separating different compartments of tissue in the leg, increases the risk. Up to 40% of athletes have fascia defects compared to 5% in athletes who don’t have symptoms. The symptoms of this condition often affect both legs and occur equally in males and females.
Compartment syndrome in children without a fracture is rare and not well understood. The most common site is the leg. One study looked at 39 cases in children and found that vascular causes were most common (28%), followed by trauma (26%), post surgery (21%), exertion (15%), and infection (10%).
Signs and Symptoms of Tibial Anterior Compartment Syndrome
When considering the possibility of compartment syndrome, it’s important to thoroughly review a patient’s past medical history. It’s equally crucial to ascertain how any trauma was caused, as both heavy impact injuries and wounds from sharp objects can trigger compartment syndrome. A doctor should determine if the patient is taking medications that prevent blood clotting. If the patient hasn’t experienced recent trauma, the doctor will then explore other possible causes, which can include poisonings, infections, complications from medical treatment, and problems with blood vessels, among others. In some cases, such as with children or patients with other injuries, available information may be limited.
People with compartment syndrome often experience intense pain. They may describe this pain as feeling deep, burning or aching, or they might liken it to a sense of fullness, swelling, or tension. Other symptoms can include a tingling or numb sensation, like pins and needles. Patients might also report that they’re unable to flex their leg or that it feels “dead” or weak.
During a physical examination, the doctor will carefully check for any evidence of skin breaks, swelling, redness, discoloration, or other signs of injury. By feeling the front of the leg, they may identify a painfully swollen muscle, which is usually most noticeable in the middle to lower third of the leg. The pain generally gets worse when the muscles are gently stretched – for example, the pain may increase when the foot is bent downwards in anterior compartment syndrome. Sensation may be reduced, especially the ability to distinguish two closely spaced points of contact. Vibration sense might also be affected. The patient may have difficulty flexing the foot, and the foot’s main pulses should be recorded.
Diagnosing chronic exertional compartment syndrome, a condition that arises during specific physical activities, requires a different approach. These patients generally experience pain that worsens during certain activities and disappears when resting. They usually know exactly when their symptoms will start and end. Despite typically having a normal physical examination result, they should be asked to take part in a physical challenge, such as running on a treadmill or outside, and then re-examined once their symptoms have returned. The doctor might then observe swelling, muscle protrusion, tenderness of the anterior compartment, pain upon downwards foot bending, and foot drop.
Testing for Tibial Anterior Compartment Syndrome
If your doctor suspects that you may have a condition called anterior tibial compartment syndrome, your personal history and a physical exam will be the main ways they assess you. The diagnosis is largely based on these factors. They’ll look for signs of specific issues like acute trauma, chronic exertional compartment syndrome, or snake venom poisoning, as these all present differently.
If you have classic symptoms of compartment syndrome in relation to a tibial fracture (a break in your shin bone), you likely won’t need further tests. Also, lab work done early in the disease typically falls within the ‘normal’ range.
The most definitive way to diagnose compartment syndrome is by measuring the pressure inside the affected compartment of the leg. This is done using a needle attached to a device which measures pressure (manometer). There are other methods available too, such as the slit catheter, microtip pressure, wick catheter, and microcapillary infusion techniques. The use of ultrasound doesn’t increase the accuracy of these pressure measurements. An absolute pressure greater than 30 mmHg, or a measurement that is less than 30 degrees between your systolic blood pressure and the pressure in your leg compartment, are both causes for concern and suggest acute compartment syndrome.
In the case of chronic exertional compartment syndrome, where symptoms are brought on by exercise, your doctor may measure compartment pressures before and after exercise to confirm a diagnosis. Generally, you would be considered to have this condition if one or more of the following apply: a pre-exercise pressure of 15 mmHg or more, a pressure of 30 mmHg or more one minute after exercise, or a pressure of 25 mmHg or more five minutes after exercising.
Typically, imaging tests like x-rays are not used to diagnose compartment syndrome. They are more commonly used to rule out other potential causes of your symptoms. That being said, the first imaging test often performed if you experience pain in the front part of your shin bone is an x-ray. In the future, infrared spectroscopy and MRI may play a role in diagnosing compartment syndrome, but for now, these tools are not widely used for this purpose.
Treatment Options for Tibial Anterior Compartment Syndrome
If an individual suffers from acute anterior leg compartment syndrome, a medical condition which consists of severe muscle and nerve pain due to excessive pressure in an enclosed space in the body, a treatment called subcutaneous fasciotomy is usually performed. Subcutaneous fasciotomy involves making a small incision in the skin to relieve the pressure. This operation could be done by either a single or double incision. During this procedure, doctors have to be particularly careful not to injure the anterior tibial artery and deep peroneal nerve, two vital structures in the leg.
The treatment also focuses on dealing with the main cause of the compartment syndrome. For instance, if the compartment syndrome was caused by a leg break, the doctor would repair the tibial fracture using a method called open reduction and internal fixation, a surgical procedure done to stabilize and heal a broken bone.
Chronic exertional compartment syndrome (CECS) is another form of compartment syndrome, which is generally less severe and happens as a result of rigorous, repetitive activities like running. It can initially be managed through simple measures such as reducing or discontinuing the causes, like certain activities, along with the use of nonsteroidal anti-inflammatory drugs (NSAIDs), which are medicines designed to reduce pain and inflammation. In addition, stretching, foot supports, physical therapy, and a change in exercise routines for around 6 to 12 weeks could be beneficial. However, for patients who do not show improvement from these approaches or refuse to modify their activities, a fasciotomy may be done. This operation has been successful in relieving symptoms in up to 90% of patients.
What else can Tibial Anterior Compartment Syndrome be?
When doctors are trying to diagnose a condition called anterior compartment syndrome, they need to rule out a range of other conditions that might be causing the symptoms. This includes:
- Infection, like skin infection (cellulitis), severe skin infection (necrotizing fasciitis), or bone infection (osteomyelitis)
- Problems with the nerves (deep peroneal nerve entrapment)
- Poisoning from a snake bite (snake envenomation)
- Blood vessel problems (deep vein thrombosis, tissue death from lack of blood supply (ischemic necrosis) or gangrene, entrapment of the artery behind the knee (popliteal artery entrapment))
- Physical injuries (to blood vessels, nerves, muscles, or soft tissues, injuries to the tibia or fibula bones)
- Muscle and skeleton problems (a condition called chronic exertional compartment syndrome, stress fractures, a condition known as medial tibial stress syndrome)
- A condition where muscle breaks down and leaks a damaging protein into the blood (rhabdomyolysis).
What to expect with Tibial Anterior Compartment Syndrome
The future health or well-being (prognosis) of an individual who has compartment syndrome depends on the cause, diagnosis, and the time it takes to start treatment after the injury. If acute compartment syndrome is treated within 6 hours with a surgical procedure called fasciotomy, a total recovery of the limb’s function is expected. After 6 hours, if no treatment is given, the tissues start to die (necrosis) due to lack of blood supply (ischemia). Therefore, 6 hours is generally considered the longest time the tissue can stay alive. Fasciotomies done on the front side (anterior compartment) of the body are usually more successful than those done on the back side (posterior compartment).
Unfortunately, if compartment syndrome isn’t diagnosed and treated early, it can lead to irreversible tissue death and permanent damage to the muscles and nerves. Patients may develop chronic pain, palsy (weakness) of the deep peroneal nerve in the front compartment of the leg, and foot drop (difficulty lifting the front part of the foot). In some cases, patients may experience Volkmann’s contracture, a condition that occurs when dead muscle tissues are replaced with new fibrous tissues leading to muscle-tendon adhesions (bands that form between tissues and organs). This can result in a lasting abnormal shape or position (deformity) and loss of function, and can occur in up to 10% of patients with compartment syndrome. The muscles can also sometimes turn hard and rigid due to deposition of calcium salts (calcific myonecrosis).
When the compartment syndrome is recurrent but doesn’t affect the blood supply (chronic exertional compartment syndrome), a fasciotomy can provide high levels of relief from pain, and most patients (between 80% and 100%) report successful outcomes.
Possible Complications When Diagnosed with Tibial Anterior Compartment Syndrome
Compartment syndrome and fasciotomy can lead to serious infections. A study once showed that almost half of the patients who had surgery to relieve pressure in a compartment of the body ended up getting infections. These infections can turn chronic. Additional complications that might occur are hematomas and seromas (basically internal bleeding and fluid-filled swelling), injury to peripheral nerves (nerves outside the brain and spinal cord), and deep vein thrombosis (a blood clot in a deep vein).
Common complications:
- Chronic infections
- Hematomas (internal bleeding)
- Seromas (fluid-filled swelling)
- Peripheral nerve injury
- Deep vein thrombosis (blood clot in a deep vein)
Patients may experience returning symptoms as recorded in various studies. The recurrence rate ranges from 2% to 17%. This might happen if all the layers of the fascia (a band of connective tissue) were not completely released during surgery, if not all the relevant compartments were opened up, or due to scarring of the fascia. In such cases, the patient might need another surgical procedure.
Recovery from Tibial Anterior Compartment Syndrome
After surgery, the first steps in care are focused on managing pain and preventing infection and swelling. Patients will start by using crutches and will gradually stop using them as they can put more weight on their legs. Both active movement and passive movement at the hip, knee, and ankle will improve over time along with the strengthening of the muscles that move the foot up and down.
Patients can expect to start walking normally about 4 to 6 weeks after surgery and should be able to run after about 6 weeks. In most cases, patients should expect to be fully recovered by 16 weeks.
Preventing Tibial Anterior Compartment Syndrome
Currently, there are no established guidelines on how to prevent the sudden (acute) or long-lasting (chronic) occurrence of compartment syndrome. Compartment syndrome is a serious condition that involves increased pressure in a muscle compartment. It can lead to muscle and nerve damage and problems with blood flow.
