Runner’s knee is by far the most common condition we see among our running population.  This condition may also be called chondromalacia patella or patello-femoral syndrome. In simple terms it is an irritation of the cartilage on the underside of the kneecap (patella).

Over the past 20 years I’ve treated and seen more than 4,000 cases of this condition.  This condition is fixable and in the vast majority of cases (I would estimate 95%) does not require that running to be stopped. 

The problem with stopping running is that after a prolonged rest you will resume running with the same characteristics as existed the before.   Therefore, I have my runner patients continue their running but with the changes indicated in this article.

The typical signs and symptoms of runner’s knee are:

-         pain going up-and even more coming down stairs

-         discomfort in the knee with prolonged sitting (called “moviegoers” sign)

-         sharp pain in the kneecap at some point during or after a run.

The knee is really two joints in one.  The main joint, where the thighbone meets the shinbone, is the joint often damaged through contact sports with injuries such as cartilage or ligament tears or sprains.  This joint does not typically injure from running.

The other knee joint is formed by the kneecap, (patella) sitting on the end of the thighbone (femur).  The underside is lined with smooth cartilage and is shaped to fit into the groove at the end of the femur.  When the knee bends and straightens, the patella tracks up and down in this groove.  During running, the patella tracking occurs under much more compression than during walking.

Unlike walking, running requires your body to be momentarily airborne.  Much of the consequent shock upon landing is absorbed by the knee.  Absorbing that shock is the job of the quadriceps (front thigh) muscle.  The harder the muscle contracts, the more compression is placed on the kneecap, and specifically, the cartilage on the underside of the kneecap.  In addition running on down-hills causes even more compression to occur than running on flats or up-hills.

The six most common causes of runner’s knee include the following.

Overloading the cartilage – a sudden increase in mileage or frequency of days run can produce a “too much, too soon” overuse effect.

Hard running surfaces – pavement (blacktop or street) is 10 times softer than cement or concrete.  Dirt or grass are the most forgiving surfaces.  Where do treadmills fall, somewhere between dirt and pavement.

Over-pronation – too much pronation causes the entire leg to roll inward, starting at the ankle.  The result is a misaligned kneecap that does not track properly in the groove of the femur.

Prolonged down-hills -  running down-hills causes greater compression of the kneecap and can also exaggerate already faulty mechanics.  The landing forces with down-hill running can go as high as 5-8 times body weight versus 3 times body weight with flats.

Improper shoes – the proper shoes not only help control pronation but also act as the initial shock absorber.  Wearing worn out shoes or picking the wrong model can lead to knee pain.

Improper running form – As I update this article in 2005, I would be remiss if I didn’t talk about running form.  We used to think that it was acceptable that each runner had his or her own form.  As for me, and a growing number of other professionals who work with runners, this is no longer the case.  Running, like tennis, golf, or any other sports skill can be learned, and proper form is critically important in order to avoid injuries and improve running efficiency and speed.

Faulty left leg alignment causing drop of hip to right and inward motion of left knee. This runner presented with left knee pain.

Over my 20 years of working with runner’s and specifically runner’s injuries, I have developed a treatment program that combines a taping technique to eliminate or reduce  the knee pain and allow running to be done comfortably.  In addition to the taping, we also video-tape each runner in order to assess his or her specific form and mechanics.

The taping technique we use is McConnell taping (named after it’s founder) or patello-femoral taping.  It has become a valuable part of treating this problem and results can be seen within the first or second run. 

In addition, strengthening, especially of the front thigh muscle must be incorporated, but only if no pain is noted.  Strengthening of the quadriceps is vital, as it is the dominant shock absorber involved during landing.  If the leg can be thought of as a shock absorber then it makes sense that by strengthening the quadriceps the shock absorbing ability would be enhanced and less injury would occur.

Last but not least we want to make sure that running form is as optimal as possible.  Optimal form can decrease knee compression by as much as 50%.  We video-tape each runner and then analyze his or her form.  If faults are found correction is taught through various drills and exercises.  The runner is then sent home to follow a specific program that has been designed to correct for all the above mentioned issues.  Follow-up visits involve reassessing the injury, checking the effectiveness of the treatment, and another session of running and videotaping to compare if form is improving.

More on the subject of running form and mechanics in an upcoming article.