Your knee is one of the strongest joints in your body because it is supported by strong ligaments and tendons, which keep the bones in place. However, the regular and often excessive strain it comes under -- from bearing your body weight and absorbing the shock of regular and more strenuous activities -- means this joint is frequently injured. One of the most common knee injuries is a cruciate ligament tear, which can be characterized by a loose feeling in the joint.
Cruciate Ligaments
Your posterior cruciate ligament (PCL) and anterior cruciate ligament (ACL) are the main stabilizing tissues in your knee joint. Your PCL stops the tibia -- one of the bones in your lower leg -- from moving too far backwards out of the knee joint, while the ACL prevents the bone from moving too far forwards, says Sportsinjuryclinic.net. ACL injuries are more common because the ligament isn't as strong as the PCL. However, it can still be damaged -- most often during contact sports, and usually due to a direct blow to the front of your tibia when your knee is bent, as in a tackle or fall.
Symptoms of a Posterior Cruciate Ligament Tear
This type of injury can be very painful and you are likely to feel it in your calf muscle as well as the knee joint, says Sportsinjuryclinic.net. The initial injury is usually followed by swelling, difficulty moving your knee and a feeling of instability in the joint. Once you are able to move your knee again, a sign that your PCL has been damaged is a loose feeling in the back of your knee and the sense that it is not adequately supported and may give way, especially when moving or running, says PreventDisease.com.
Diagnosis
Your physiotherapist will diagnose this type of injury by performing a series of tests. While you are sitting on a bed or table with your injured leg straight out in front of you, the physiotherapist will hyperextend your injured leg, a movement that will be painful if your PCL is damaged, says Sportsinjuryclinic.net. With your injured leg bent and the foot flat on the bed, he may also push on the top of your tibia to determine how much it moves backwards compared to the uninjured leg. This is called the posterior drawer test and it indicates a weakened PCL if the movement on the injured leg is greater than on the other leg. For the posterior sag test, you will be asked to raise your injured leg and bend it at 90 degrees. A significant dip where the tibia meets your knee -- that is greater than that on the uninjured leg -- is another sign that you may have a PCL injury.
Treatment
The initial treatment for this type of injury is always rest, applying ice to the area, compressing it with a bandage and keeping your leg elevated, says Sportsinjuryclinic.net. In the later stages of recovery, your doctor or physiotherapist is also likely to recommend strength and mobility exercises. These may include standing hamstring holds, lunges and squats, says Sportsinjuryclinic.net. For the hamstring holds, bend your injured leg back to 90 degrees, hold for 20 seconds and repeat three times. When doing squats, start by lowering just a quarter of the way and gradually building up to a 90 degree squat, as your PCL strength improves.
