Compartment syndrome on the lower leg
The compartment syndrome is a surgical and intensive care emergency that should not be underestimated. Compartment syndrome is swelling and damage to a muscle compartment that steadily worsens on its own and can lead to severe muscle damage within a few hours.
A compartment describes a delimited box that includes several muscles and possibly arteries, veins and nerves. The muscle cords are encased by so-called fasciae, separated from one another and divided into the various compartments. The fasciae are very tensile and tear-resistant connective tissue sheets that do not expand elastically in the event of swelling and therefore exert pressure on the muscles.
Read more about the compartment syndrome on our main page: Compartment syndrome (log syndrome).
The most common causes of compartment syndromes are accidents and operations.
The former can trigger a compartment syndrome in several ways. On the one hand, a blunt bruise and compression of the muscles can lead to entrapment, minor bleeding and swelling. A typical cause of this is a heavy object that falls on the lower leg.
On the other hand, a fracture in the tibia, for example, can damage the muscle. For example, individual bone fragments can cut muscles and put pressure on the compartment.
Operations are also a common cause of the compartment syndrome on the lower leg. For example, after surgical treatment of a broken bone, minor bleeding can lead to dangerous swellings in a muscle box. Surgical interventions always involve manipulation and damage to the tissue and are associated with minor bleeding, most of which are stopped during the operation.
Muscle edema after excessive exercise is a very rare cause of a compartment syndrome. This can develop on the lower leg after running a marathon, for example, and it causes a chronic compartment syndrome. For an acute compartment syndrome to develop, however, the swelling must be sufficiently strong.
Minor swellings and bruises can initially be compensated within the muscle box until the body absorbs the fluid. However, if there is sufficient swelling, a vicious circle is created, which makes the compartment syndrome worse on its own. Once the pressure in the muscle box is so high that the venous return of the blood is impeded, the swelling continues to increase until the arterial blood supply is also impaired. From this point onwards, the muscle is not supplied with sufficient blood, which means that there is an acute need for action and irreversible consequential damage can occur.
The diagnosis of acute compartment syndrome is based on clinical symptoms. The diagnosis and therapy decision are made very generously with this clinical picture, as the disease quickly takes a dangerous course and from a certain point onwards cannot be compensated by the body itself.
A typical accident involving compression of the lower leg or a recent operation together with the symptoms are sufficient criteria to initiate surgical treatment.
In addition to the external inspection, the assessment of the lower leg should also include palpation of the lower leg, provided that the pain is tolerable. In the case of a clear compartment syndrome, induration and pressure increase can be felt. If the situation is unclear, the exact pressure in the muscle box can be measured intraoperatively using a probe.
How is a measurement carried out?
The measurement must be carried out sterile. For this purpose, special probes are used that can precisely indicate the pressure. The probe can be placed invasively under the fascia of the affected muscle compartment and measure the pressure directly in the compartment. The exact position should be checked using ultrasound. The measurement can be another indicator of an operation.
The measurement can also be carried out with chronic compartment syndrome, even under stress. This can be used to estimate the exact extent and potential damage to nerves, veins and arteries.
These symptoms indicate a compartment syndrome in the lower leg
The main typical symptom of compartment syndrome is pain. This occurs spontaneously and suddenly and is localized in the muscle.
Moving, stretching, and contracting the muscle can make the pain worse.
This is later followed by muscle weakness, sensory disturbances and tingling, which suggests damage to the nerves and arteries is already taking place.
The swelling and tension can also be felt externally in the form of hardening. The skin of the shin or calf can be visibly stretched and shiny.
Depending on the cause, red and blue hematomas or fresh operation scars can be seen on the outside. Overall, a slight swelling of the entire lower leg can also be seen externally.
You might also be interested in the following article: Pain in the lower leg - these are the causes.
On the shin
The compartment syndrome is most common on the tibia. In the muscle compartment of the tibia, the compartment syndrome can on the one hand occur more favorably, on the other hand it can be accompanied by particularly devastating consequences. This is also where the nerves and large arteries of this muscle group run, which are primarily responsible for lifting the foot and toes.
In addition to the acute compartment syndrome, a chronic course can also occur in this muscle box. Here, those affected often notice swelling and pain when walking. Since this is a rapidly progressing disease with a high potential for long-term damage to various structures, an operation must be carried out quickly in most cases.
Also read our article: Pain in the shin - what are the causes?
On the calf
The calf is affected by a compartment syndrome much less often than the muscle group on the shin. The calf is made up of a larger proportion of soft tissue and contains several muscle boxes.
The difficulty in diagnostics is to identify the causative muscle group, as both superficial and deep-lying boxes can be responsible. If the nerve that runs in the calf is involved, there may also be restrictions in the downward flexion of the foot and in the rotation of the lower ankle. The exact measurement of the pressure within the fascia is difficult in deep compartment syndromes.
This is also a highly acute disease, which is why the diagnosis and indication for surgery are given generously.
Treatment can be causal and symptomatic.
Symptomatic therapy consists primarily of pain relief, which is urgently needed in the case of the compartment syndrome. This can be done with pain medication from the group of NSAIDs. Which includes Ibuprofen, Diclofenac or Indomethacin. In the hospital, if the pain is enormous, pain medication can also be administered intravenously.
In the case of the compartment syndrome on the lower leg, however, causal therapy must come first. A mild, initial or latent chronic compartment syndrome can possibly be treated with rest, elevation and cooling. This reduces the metabolism in the muscle, which reduces swelling and bleeding and thus reduces the pressure in the muscle compartment.
The alternative to conservative therapy is surgery. In most cases of acute compartment syndrome, it is necessary to prevent serious consequential damage. The operation directly relieves the pressure on the compartment, which reduces the acute pressure and allows the causal injury and any damage that has already occurred to heal.
When do you need an operation?
In most cases, the operation is necessary in the case of compartment syndrome.
The mechanism by which the compartment syndrome develops shows that a certain amount of pressure in the muscle compartment sets a vicious circle in motion, which means that the pressure continues to increase until nerves and muscles die with serious consequences. For this reason, surgery should be done too early rather than too late.
A slight increase in pressure can be tolerated by the muscles and fasciae. However, if the pressure increases so much that the small and large veins are compressed and the oxygen-poor blood is no longer transported away, the body is no longer able to release the pressure itself and an operation must be performed as quickly as possible.
Procedure of the operation
The procedure of the operation is very simple. After the skin incision, the affected muscle box must first be visited. The suspicion of the compartment syndrome can be confirmed again by means of intraoperative pressure measurement. The fascia surrounding the muscle is then cut and split. The adjacent fasciae are also split.
The wound can then be left open to give the muscles time to swell. Later, the wound can be closed again or, if not possible, a small skin graft can be performed.
Overall, the risks of compartmentalization are low. Since every surgical procedure is a violation of the anatomical structures, minor or major complications can occur. These include infections that cause superficial irritation or deep abscesses.
Furthermore, injuries to muscles, veins, arteries and nerves can occur during surgery on the lower leg, which lead to corresponding complications. The operation can also cause new compartment syndromes. The large wound, which is often only closed after the swelling has subsided, can lead to pronounced scarring and contractures, which cause visual and functional problems.
The prognosis strongly depends on the extent to which the compartment syndrome was present and how early the therapy was started.
If the rise in pressure is corrected quickly so that blood flow is guaranteed permanently, the prognosis is good. Functional restrictions of the muscles and sensitivity disorders are a bad sign and indicate that damage to the vascular and nerve tracts has begun. However, even in these cases, the functions can often be fully restored.
Dead areas, so-called "Necrosis“, Cannot recover. If the blood flow is deficient for a long time, the muscle tissue can become necrotic. The necroses must then be surgically removed; in the case of particularly pronounced necroses, the entire area must be amputated. This represents the extreme case of a compartment syndrome on the lower leg.