Posterior Cruciate Ligament (PCL) Injury
The posterior cruciate ligament (PCL) is not injured as frequently as the ACL. PCL sprains are usually caused by the ligament being pulled or stretched too far, a blow to the front of the knee, or a simple misstep.
PCL injuries disrupt knee joint stability because the shinbone can sag backwards. The ends of the thighbone and shinbone rub directly against each other, causing wear and tear to the thin, smooth articular cartilage. This abrasion may lead to arthritis in the knee.
Signs and symptoms
- Marked, immediate swelling (within three hours of the injury)
- Difficulty walking after the injury
- Pain during knee movement
- A feeling of instability or the knee ‘giving way’
To determine the extent of the injury, the physician relies on an account of the accident, a visual examination, and several diagnostic tests. The doctor will need to know if you have a history of knee injuries. During the examination, the injured leg will be compared with the normal leg and see if there is any sag or movement in the shinbone. PCL injuries may be isolated or combined.
Isolated PCL injuries:
Can usually be treated non-surgically
Do not involve any other structures in the knee
May be either partial or complete tears
Combined PCL injuries
May involve injury to other ligaments, bone, nerves or blood vessels
Usually require surgical repair
An MRI (magnetic resonance image) can be used to confirm the diagnosis. X-rays do not show ligaments, but they can reveal any associated damage to the bones and cartilage. For example, if the PCL is torn completely from its attachment to the shinbone, it may take a piece of bone as well - this is called an avulsion fracture and can be seen on an X-ray.
The type of injury dictates the type of treatment you need. For minor PCL tears, the initial treatment follows the acronym ‘RICE’: rest, ice, compression and elevation. You may have to use crutches for a short time, and your doctor may prescribe some anti-inflammatory drugs such as aspirin or ibuprofen. After the swelling subsides, you will need to follow a program of physical therapy to strengthen your quadriceps muscle and regain range of motion.
Some patients require surgery to stabilise the knee. Arthroscopic (‘key-hole’) surgery, which uses small incisions and pencil-sized instruments, is used to determine and repair damage to the cartilage in the knee. Avulsion fractures may need to be fixed with internal screws to ensure proper healing. If the PCL is completely torn, it may be reconstructed using a portion of the patellar tendon or some other graph.
Patients with PCL tears often do not experience instability in their knees, so surgery is not always needed. Many athletes return to activity without significant impairment after completing a prescribed rehabilitation program.
However, if the PCL injury pulls a piece of bone out of the top of the shinbone, surgery is needed to reattach the ligament. This procedure usually results in good outcomes in relation to knee function.
The goals of rehabilitation are to restore range of motion and to strengthen the quadriceps muscles which help stabilise the knee. After surgery, you may have to use crutches and a knee brace. Exercises such as squats and leg presses are used because they put less stress on the knee. Full recovery takes several months.