The patella, commonly referred to as the "knee cap", and its tendon transmit power from the quadriceps to the lower leg. Normally, as the knee bends, the patella slides smoothly along a groove in the thigh bone. However, under certain conditions the patella may experience forces which push it against the sides of the groove, causing pain. Additionally, inflammation and roughening of the smooth underside of the patella may occur. Collectively, this process is referred to as patellofemoral syndrome (PFS). Some of you may be familiar with the older term, chondromalacia patella.
PFS is one of the most common causes of knee pain in runners. The pain is usually located in the front part of the knee, but may be on the inside, outside, or vaguely located. The pain can feel either sharp or dull, and is often made worse by squatting or walking down stairs. Sometimes there is grinding or clicking. Predisposing factors include,
Treatment involves rest, ice, anti-inflammatory medications, and taping. Taping can supply immediate pain relief and helps correct abnormal positioning of the patella. It is continued until stretching and strengthening exercises re-balance the patella. Soft tissue therapy and stretching help loosen tight structures. The exact stretch depends upon which muscles are tight. Once pain has resolved then strengthening exercises can be started to prevent the condition from returning.
A frequent finding in runners with PFS is a weak VMO muscle. Isolating and strengthening this muscle will help keep the patella in its groove and there are several useful exercises that accomplish this. All should be done without pain.