Anterior Knee Pain Syndrome

What is it?
The term “anterior knee pain” (AKP) is a general term describing the very common affliction of pain in the front of the knee, generally felt under or around the patella (knee cap). The symptoms most people experience typically include occasional sharp pain in the front of the knee that may be hard to localize exactly. Many people have pain going up or down stairs, with going down stairs often being worse. Many people have pain after sitting for long periods of time, such as when driving or watching a movie. Most patients have pain with squatting down or doing a deep knee bend. It is common in runners and women in particular, although anyone may experience this.

What causes it?
There are many things that can cause this pain, but for the most part the exact cause remains a mystery. It is believed that the pain is from patellar tracking abnormalities and subsequent cartilage wear under the patella, called patellar chondromalacia. This may lead to abnormal pressure on the patellar subchondral bone which has nerves in it that transmit pain signals to the brain. The cause of the tracking abnormality may be from any number of muscular imbalances, usually from relative weakness in the quadriceps muscles (the thigh muscles). It is common to experience AKP after a mild or major knee injury, because the quadriceps muscles may be partially injured and may not guide the patella in the groove on the femur in a normal way. Some patients have a predisposition to this because of the way their legs are built. Patients with knock knees (high quadriceps or “Q” angles) may have higher pressures on the subchondral patellar bone and may be more likely to have this condition.

What is the conservative (first line) treatment?
Anterior knee pain is a frustrating problem to treat, because there is no “quick fix”. The best line of treatment is to work on strengthening your quadriceps muscles (specifically the muscle called the vastus medialis). This is thought to help pull the patella into the groove and helps stabilize the knee, and is almost always successful if done thoroughly and consistently.

Another line of therapy is to avoid aggravating activities. Many times, the pain is from a specific cause, such as overtraining for a running race. Try to avoid deep knee bends such as squatting. Until your pain gets better, you may even have to do stairs using the same leg for each step. Go up with your good leg first, and down with your bad leg first. Remember: “up with the good, down with the bad”. You may want to ice the front of your knee when the pain is more severe. Do this for 20 minutes, several times a day. Also, a patellar sleeve may help relieve symptoms and help get you back to doing sports. For the rare case, corticosteroid injections may help relieve symptoms.

What if all that fails to relieve my condition?
Although therapy almost always works, if the therapy does in fact fail, surgery may help. Depending on the specific anatomy of your patellar tracking, you may be a candidate for an arthroscopic lateral release (this helps the patella track more normally) with or without a medial capsular plication or you may need an open realignment surgery. It is important to realize that there are other conditions such as arthritis that may need very different treatments.

How successful is surgery for this?
Surgery is successful only if a specific abnormality can be identified. If this can be found, you can expect good results with surgery in the majority of cases.

What can I do to prevent this from happening again?
Keep your knees strong and stay active. Working on quadriceps strength can help prevent this from coming back.