This type of injury results from the tearing of the posterior cruciate ligament (PCL) in its fibers or at its attachment to the femur or tibia.
Immediately after injury, the knee swells rapidly over the next 3 to 6 hours. Swelling makes the knee stiff and painful, with difficulty walking. Later on, pain and weakness set in. The knee sometimes dislocates at the time of the tear.
The injury usually occurs after a fall on the knee or a strong blow to the front of the lower leg, just below the knee. This injury often occurs during sports or running.
If untreated, the knee may repeatedly give way. This can lead to additional injury and possible arthritis.
Pre-season conditioning before participating in a sport is the best prevention. Sports safety guidelines for adults, adolescents, and children should be followed.
Diagnosis is based initially on history and physical exam. A bruise on the front of the leg just below the knee may be noticed as well as a swollen knee joint. Joint x-rays may be normal. Sometimes swelling or a chip of bone broken off the tibia at the back of the knee joint may be shown. An MRI scan confirms the diagnosis.
Treatment depends on the degree of instability, the person's age, and anticipated future activities. Initial treatment is a brief period of RICE (rest, ice, compression, and elevation). Non-steroidal anti-inflammatory medications (NSAIDs) such as ibuprofen (i.e. Advil, Motrin) or naproxen (Naprosyn, Aleve, Anaprox, Naprelan) can help relieve pain.
An exercise program may help to regain motion and strength of the knee, especially the upper thigh. For the young athlete, surgical reconstruction of the ligament may be appropriate. In an older, non-athletic person, a non-surgical approach, such as a brace, may be chosen. Physical therapy is generally ordered after surgery.
NSAIDs may have adverse effects on the stomach, liver, or kidneys.
PCL injury can result in serious damage to the nerves or the artery behind the knee. Treatment may not be successful in restoring stability to the knee. Stiffness and weakness of the knee may remain. Infection is possible after any operation.
The person will be asked to observe for symptoms of instability, with repeated episodes of pain, swelling, giving way, or locking of the knee.