The knee is stabilized by four main ligaments: 2 collateral ligaments (medial and lateral) and 2 cruciate ligaments both anterior (front) and posterior (back). The cruciate ligaments attach to the femur (thigh bone) and travel within the knee joint to the upper surface of the tibia (shin bone). The ligaments pass each other in the middle of the joint forming a cross shape, hence the name ‘cruciate’. Functions of Posterior cruciate ligament
The posterior cruciate ligament (PCL) functions mainly in preventing the tibia from traveling backwards on the femur, known as posterior drawer. It also helps to prevent the tibia from twisting outwards. Injury to the ligament leads to knee instability with the shin bone having a tendency to ‘sag’ backwards when the knee is bent at 90 degrees.
The incidence of injuries of the PCL is less than that of the anterior cruciate ligament. This is mainly due to the greater thickness and strength of the PCL. Nevertheless, the most common way in which the PCL is injured is by direct impact to the front of the tibia itself, usually when the knee is bent. This may occur in a front-on tackle or collision or when falling with the knee bent. The injury is commonly associated with injuries to other structures in the rear compartment of the knee joint such as lateral meniscus tears. In addition the articular cartilage may also be damaged.PCL tears are graded I- III with III being the most severe. These gradings are classified depending on the amount of backward tibial displacement observed when the knee is bent at 90 degrees. In extreme cases the ligament may become avulsed, or pulled off the bone completely.
Ø Pain at the time of impact which, over time, may also be felt in the calf region.
Ø Pain while kneeling and squatting
Ø Swelling, although this may be minimal
Ø Positive sign on the ‘Posterior draw test’.
Ø Pain and laxity when a ‘reverse Lachman’s test’ is performed.
Ø Walking with limp
Ø Feeling of instability or looseness in the knee, or the knee gives way during
Ø Pain with running, slowing down, or walking up or down stairs or ramps
Causes:-The PCL can tear if your shinbone is hit hard just below the knee, or if you fall on a bent knee. These injuries are most common during
§ Motor vehicle accidents. A so-called dashboard injury occurs when the driver’s or passenger’s bent knee slams against the dashboard, pushing in the shinbone just below the knee and causing the PCL to tear.
§ Contact sports. Athletes in sports such as football or soccer may tear their PCL when they fall on a bent knee with their foot pointed down. The shinbone hits the ground first and it moves backward. Being tackled when your knee is bent also can cause this injury. Other causes include bending or extending your knee past its normal position and getting hit on the side of the knee while your leg is twisted
§ Medical history-doctor will ask about the mechanism of injury and the difficulties faced by you at present ,since how long you’ve had symptoms and whether you have a history of knee injuries.
§ Physical examination of the knee. Your doctor may press on your knee to feel for injury, looseness or fluid in the joint from bleeding. He or she may move your knee, leg or foot in different directions and ask you to stand and walk to see if your knee stays in proper position. Your doctor will compare your injured leg with the healthy one to look for any sagging or abnormal movement in the knee or shinbone.
§ Posterior drawer test. In this test, you lie on your back with your knee bent. Your doctor gently moves your lower leg backward at the knee. If the leg moves back too far, your PCL is torn.
§ X-ray. An X-ray picture of the bones and tissues in your knee joint won’t show a PCL injury, but it can show damage to bones and cartilage, a sagging shinbone or an avulsion fracture.
§ Magnetic resonance imaging (MRI). This painless procedure uses magnetic fields to create computer images of the soft tissues of your body. An MRI scan can clearly show a PCL tear and determine if other knee ligaments also are injured.
§ Arthroscopy. If it’s unclear how extensive your knee injury is, your doctor may use a surgical technique called arthroscopy to look inside your knee joint. A small, lighted optic tube is inserted into your knee joint through a small incision. The doctor views images of the inside of the joint on a computer monitor or TV screen.
What can the athlete do after sustaining a PCL injury?
Apply RICE (Rest, Ice, Compression and Elevation) as soon after the injury as possible.
Ø Manual therapy treatments
Ø Specific rehabilitative exercise program which may include: quadriceps and hamstring strengthening, gait reeducation and balance training using wobble boards.
Ø Sports specific training
The more extensive your PCL injury, the more likely it is that your knee will feel unstable. It may give out during physical activities, such as running, slowing down, or walking up or down stairs.If your injury causes episodes of knee instability, the cartilage in your knee can become torn and you may develop arthritis in the joint.
Unfortunately, most PCL injuries happen during accidents that usually aren’t preventable. But these suggestions may help you avoid an injury:
§ Do strengthening exercises for your upper leg muscles (quadriceps and hamstrings),
§ Maintain a good leg-stretching routine.
§ Use proper techniques when playing sports or exercising
Visit physioline for further treatment and rehabilitation