A ruptured posterior cruciate ligament is an accidental injury. It occurs relatively rarely and is often recognized late. A precise diagnosis is therefore important in order to avoid consequential damage.
What is a posterior cruciate ligament tear?
The posterior cruciate ligament is the thickest and most important ligament in the knee joint. It ensures that the lower leg does not slip behind the thigh bone at the base of the knee joint.
Due to the position and thickness of the ligament, a posterior cruciate ligament tear is much less common than a tear in the anterior cruciate ligament. Because this injury requires a lot of force, a rupture of the posterior cruciate ligament rarely occurs in isolation.
It is usually accompanied by other injuries to the knee, so it can easily be overlooked and then left untreated. In this case, the originally acute injury can take on a chronic form. This can cause consequential damage.
Causes
Tears of the posterior cruciate ligament occur when the maximum stretching of the ligament is exceeded. This often happens in the case of so-called speed trauma, which refers to injuries in which a sudden strong force acts on the knee.
This can happen in motorcycle, bicycle or car accidents. It is a well-known phenomenon from car accidents that the impact of the knee against the dashboard pushes the lower leg backwards, which can cause a tear in the posterior cruciate ligament. However, this is becoming increasingly rare as a cause of injury.
Much more common is a posterior cruciate ligament rupture as a result of a sports injury, such as a fall on a bent knee or impact trauma from an opponent, as is more common in American football, for example. This often leads to further injuries of the knee to the joint capsule or to other ligaments.
Symptoms, Ailments & Signs
A posterior cruciate ligament tear is sometimes expressed by a clear cracking or tearing. Patients often experience a feeling of displacement in the knee, accompanied by an unusual feeling of pressure. This is followed by severe pain, which subsides after a few minutes. In the further course, the pain occurs especially when the affected leg is put under pressure.
The symptoms are usually most severe when climbing stairs or squatting, which is why those affected usually adopt the typical, slightly bent position with their knees. The knee swells, which can lead to restricted movement. The injury to blood vessels causes a bruise in the area of the joint, which, however, subsides quickly.
In the first few days after the injury, the knee feels unstable and cannot move as before. Those affected do not always notice a cruciate ligament rupture immediately. Sometimes the injury first manifests itself as an increasing insecurity when walking and a pulling in the knee. In addition, the knee buckles even at low loads. In general, a posterior cruciate ligament tear causes generalized knee pain that, depending on the severity of the injury, can radiate to the upper and lower leg or even to the foot.
Diagnosis & History
Since a rupture of the rear cruciate ligament is comparatively rare and is usually associated with numerous accompanying injuries due to the force required for it, it is easily overlooked.
For this reason, a particularly thorough diagnosis is important for knee injuries. The affected knee is usually swollen and nonspecifically painful. Bruising may be visible. A description of how the accident happened gives initial indications of the extent and type of damage to the knee, and a careful examination of the knee joint using special tests is essential. Associated injuries to the inner and outer ligaments should be checked, including cruciate ligament injuries and tears to the inner or outer ligaments.
The so-called rear drawer is tested, with the lower leg being pressed backwards against the thigh. X-rays and magnetic resonance imaging ( MRI ) are also part of the diagnosis. In order to measure the extent of the drawer movement of the lower leg, functional X-rays, so-called held images with the help of a device designed for this purpose, can be useful.
However, even with an MRI, a tear in the posterior cruciate ligament can be difficult to detect because the ligament is relatively well supplied with blood. An injured ligament can also heal on its own, but then usually remains elongated. The resulting instability of the knee can become chronic in this way. As a result of the wrong sequence of movements, cartilage damage occurs, which can lead to arthrosis in the knee within a few years.
Complications
Unfortunately, in many cases the diagnosis of this injury is delayed, which is why complete healing is often not possible. Torn cruciate ligaments often cause severe knee pain. This pain often spreads to other regions of the body and can also lead to sleeping problems at night in the form of pain at rest.
The knee is often swollen and bruised. The knee is often also unstable, so that the patient can no longer easily carry out heavy physical work or sports. The quality of life of those affected is significantly reduced by the cruciate ligament tear. Gait uncertainties continue to occur and the affected person often takes a gentle position, which, however, has a negative effect on their health.
The pain and limitations can also lead to psychological problems and possibly to depression. This complaint is usually treated with therapy or with the help of an operation. There are still no particular complications.
However, a positive course of the disease is not always possible, so that the person affected may suffer from limitations throughout their life. It may then also no longer be possible to carry out certain sports. Life expectancy is not reduced.
When should you go to the doctor?
If there are sudden complaints during movements, a cracking noise and problems with locomotion, the leg should be immobilized. The complaints occur in the knee area and can occur during sporting activities as well as everyday movements. A doctor is needed in the event of a cruciate ligament tear, but the person affected can already take some supportive measures on site that have a positive influence on the further course.
If possible, the leg should no longer be loaded and should be cooled until the medical examination. In the case of swelling or discoloration of the skin, a medical clarification of the symptoms is necessary. Clothing on the knee should be removed to avoid tightness or blood flow problems. If you experience pain, unsteady gait or a loss of strength in the leg, there is cause for concern. In a euphoric mood, those affected often notice belatedly that a ligament tear has occurred. You notice a shaky feeling in the usual movement sequences and should see a doctor for a check-up.
In the event of sudden bruising, sensory disturbances or abnormalities when touched, a doctor’s visit is necessary. If the knee stiffens or the knee joint is particularly unstable, a doctor is needed. People with knee disorders should be extra cautious and not wait until treatment.
Treatment & Therapy
A tear in the posterior cruciate ligament is a relatively serious injury, but usually heals well with conservative measures. In the course of such non-surgical treatment, the knee is first immobilized in a special splint or stabilized with a splint that allows limited movement.
This prevents the lower leg from sliding back against the thigh at rest or when moving. This splint is usually worn for around six weeks. The supporting muscles, especially in the thighs, are strengthened through physiotherapeutic exercises. If the rest of the ligaments are also affected, an operation is recommended. Similar to the more common anterior cruciate ligament tear, the damaged posterior cruciate ligament is replaced by transplanting an endogenous tendon. However, the procedure is more complicated than in the case of a tear in the anterior cruciate ligament.
The success of the operation depends not least on how carefully the follow-up treatment is carried out in order to avoid consequential damage such as restricted mobility or arthrosis in the knee. After the operation, a sturdier splint must be worn for about six weeks, and then a splint that allows the first movements. An accompanying lymph drainage is recommended, a precisely coordinated physiotherapy is absolutely necessary.
After a longer period of rest for recovery, movement exercises are only carried out passively in the first few weeks, later the first weight-bearing exercises are added, which are increased very slowly. If the therapy is successful, the injury is considered healed after about six months. After about a year, the leg can be fully loaded again. The extent to which certain sports can be carried out or are recommended must be decided on a case-by-case basis.
Outlook & Forecast
The difficulty of the posterior cruciate ligament tear lies in the correct and quick diagnosis. The tear is often overlooked or the existing injury misdiagnosed. This delays appropriate treatment and can cause complications or problems in healing. If the tear is documented promptly after the accident or fall in a comprehensive and thorough diagnosis, a full recovery can be achieved with optimal medical care.
Normally, the patient gets a good prognosis, since the posterior cruciate ligament rupture heals completely if certain specifications are taken into account. The healing process takes several weeks or months and involves immobilization of the knee joint. The sooner this happens and the less stress is placed on the joint, the shorter the healing path. Restricting the movement of the knee is essential. Some patients require surgery. If this proceeds without further complications, the patient can also be discharged from the treatment after a few months as symptom-free.
In both cases, targeted training and exercise units should be used after wearing a splint for fixation. Your goal is to build up the existing muscles again as quickly as possible. If medical care is denied, there can be lifelong impairments in locomotion.
Prevention
A tear in the posterior cruciate ligament can only be prevented by avoiding high-risk sports such as American football or hockey. Strengthening the muscles and regular strength training relieve the knee joint and can further reduce the risk of a posterior cruciate ligament rupture.
Aftercare
Even during conservative treatment or before the operation, the patient should independently begin exercises to tighten the thigh muscle. The attending doctor or physiotherapist instructs the patient accordingly and goes through the exercises in detail. However, aftercare for an injury to the posterior cruciate ligament must be very moderate and gentle in comparison to other ligament injuries.
After the operation, the patient receives what is known as a PTS splint. This usually remains on the patient for six weeks. With the PTS splint, a pad on the lower legs ensures that they are pushed forward. This protects the posterior cruciate ligament replacement. In the first six weeks, exercises are only carried out very passively and in the prone position.
It is not yet possible to put any weight on the affected leg. First, exercises are carried out with a maximum weight of ten kilograms. After two weeks, the load weight can be increased to twenty kilograms. The practice period should also be around two weeks. After that, you can bear half your body weight (under supervision).
Here, too, the load should be kept constant for at least two weeks and not increased further. A special posterior cruciate ligament splint is used from the 6th postoperative week. The leg can now be bent by about 90 degrees and the full body weight can be applied.
You can do that yourself
Athletes should take a break of at least six months after a rear cruciate ligament tear. Activities that put a lot of strain on the knee should also be avoided in the first few months after the operation. Cooling and rest are indicated immediately after the operation. Comprehensive aftercare ensures that the swelling decreases quickly and the pain disappears.
Along with this, stretching is important. The joint is passively moved and stretched using a motor splint. A knee brace is useful in the first six weeks after an operation, because it allows the leg to be stretched without overstretching the affected joint. Accompanied by a physiotherapist, the thigh muscles must be strengthened. Especially in the first few weeks, it is important to regularly compare the intensity and scope of the exercises and applications with the current condition of the knee. At home, the patient can do squats or exercises on the ergometer.
The doctor in charge can best answer which measures are permitted. After the six-month break, you should start exercising again very slowly. The sufferer may use a special brace to protect the posterior cruciate ligament from further injury.
