Ask Dr. K: Length of PCL rehabilitation depends on pain

The ACL and PCL connect the thighbone (femur) and the large bone of the lower leg (tibia) at the knee joint. The ACL and PCL form an “X” pattern that stabilizes the knee against front-to-back and back-to-front forces. (I’ve put a detailed illustration of the knee joint on my website, AskDoctorK.com.)

A PCL injury is a sprain — a stretch or tear of the ligament. PCL sprains are classified as follows.

— Grade I: a mild injury that causes only microscopic tears in the ligament.

— Grade II (moderate): The PCL is partially torn, and the knee periodically gives out when you stand or walk.

— Grade III (severe): The PCL is either completely torn or is separated from the bone that it anchors. The knee is more unstable.

People get PCL injuries when their knee is flexed (like when you are seated) and the large bone of the lower leg is hit hard. For example, a person might be seated in the front seat of a car. If the car is in an accident and the person’s lower leg smashes into the dashboard, that could cause the injury.

Usually, people with a sudden new PCL injury notice less of a problem with the knee than people with a new ACL injury, at least at first.

Treatment of all PCL sprains should begin with RICE:

— Rest the joint.

— Ice the injured area to reduce swelling.

— Compress the swelling with an elastic bandage.

— Elevate the injured area.

Your doctor may also recommend a nonsteroidal anti-inflammatory drug (NSAID), such as ibuprofen, to relieve mild pain or swelling.

Further treatment depends on the severity of your injury. If you have a Grade I or Grade II sprain, your knee may be splinted in a straight-leg position, and you’ll begin an intense rehabilitation program. Rehab gradually strengthens the muscles around the knee, supports the knee joint and helps protect the knee from re-injury.

If you have a Grade III sprain and the PCL has been pulled away from the bone, it may have to be surgically reattached with a screw. If your PCL has torn completely, it can be surgically reconstructed. After surgery, you’ll wear a long-leg knee brace and gradually begin rehabilitation.

Full recovery can take from four months to a year. How long your specific injury lasts will depend on the severity of your PCL injury and your rehabilitation program. Probably the most important thing you can do are exercises to strengthen your quadriceps muscles — the muscles in the front of your thigh. The chances are good you will return to your pre-injury level of function.

Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.