Runners knee, medically known as chondromalacia patellae is knee pain that actually originates from the foot. Most knee pain is due to an inherent problem within the knee, but this knee problem is caused by overuse of the feet seen primarily in runners. Although rare, I have seen it in people who do a lot of walking as well.
This pain will continue during the remainder of the run but in many instances the pain can become so bad that the runner is forced to stop. Generally the pain will continue throughout the remainder of the day but usually the pain is gone the next day only to reoccur if the patient starts to run. Keep this description in mind because it generally distinguishes runners knee from other knee problems.
True runners knee is caused by a deviation in foot biomechanics (the way the foot functions when walking or running). It is generally caused by a condition known as pronation.
During the gait cycle when the affected foot hits the ground in most people it flattens out somewhat to allow the body to propel over the foot and bring the other foot and leg forward. To better understand the gait cycle, click here. During this flattening out of the arch (pronation) part of the pronatory component is for the lower leg below the knee to internally rotate.
The problem is when there is too much pronation and therefore too much internal rotation of the lower leg, because at some point during this part of the cycle the upper leg has to begin externally rotating, due to the alignment of the hips to the feet. So, you reach a point where the upper leg is externally rotating and the lower leg is over internally rotating.
Below is a picture of what is happening to the left leg of a runner who is over pronating.
As one might easily guess this causes a tremendous twisting pressure at the level of the knee. (The top of the knee is twisting in one direction and the bottom of the knee is twisting in another direction). Excessive pronation will increase the angle of patellae tendon attachment into the top of the lower leg (tibia) from a normal angle of 0-15 degrees to upwards of 30 degrees. This will cause the knee cap (patellae) to become irritated and painful.
Using the description of symptoms previously discussed makes treatment very easy. The best way to treat this condition is to eliminate or dramatically reduce the amount of pronation in the affected foot. It has amazed me over the years how dramatic and immediate the relief is.
The best way to accomplish this is through the use of orthotics. With the use of an orthotic the excessive pronation is eliminated, the lower leg is no longer internally rotating while the upper leg is attempting to externally rotate and the stress on the knee is no longer present.
Sometimes if the relief from runners knee is not as a dramatic as described I have my runners supplement their treatment with the following: I recommend one Advil or Motrin or equivalent thirty minutes before their workout. Additionally, I recommend icing the knee for a few minutes before the run and immediately afterward. This helps reduce inflammation, but I consider this a short term solution.
Keep in mind this advice will only help knee pain that is a result of over pronation at the level of the foot. As stated earlier most complaints of knee pain is due to problems within the knee itself such as cartilage degeneration, torn ligaments or bursitis to name a few. Generally, an orthotic will not help any of those conditions and a knee specialist should be consulted.
As long as we are on the subject of knee pain related to foot malfunction there is one other not so common problem seen in the knee that may be related to improper foot function. This is seen in a foot that exhibits too much supination.
In this case the foot acts as a very poor shock absorber and all the shock that the body picks up when the heel hits the ground is sent up through the leg. This can manifest itself as pain in the knee area particularly on the outside (lateral) part of the knee.
The best way to combat this is through the use of a shock absorbing type orthotic. A foot specialist can fit you for one of these. Most of the over the counter orthotics do not do a good job of absorbing shock.
Since this problem is essentially a biomechanical problem where there is too much rotation around the knee joint, as a result of excess pronation, there are no exercises that will eliminate the problem. Exercising the muscles that attach and support the knee will only result in marginal improvement. The only treatment is control of excess pronation, generally through the use of an orthotic.