Chondromalacia patellae (also known as CMP, Patello-femoral Pain Syndrome, or Runner's Knee) is a term for a large and disparate group of medical conditions that can cause pain in the front of the knee. It is common in young adults, especially soccer players, cyclists, rowers, tennis players, ballet dancers, horseback riders, volleyball players, and runners.


The typical patient is a teenage girl complaining of pain in the front of her knee around the knee-cap. She may also have pain that is deep-seated that may radiate to the back of the knee. The pain comes and goes, but usually with squatting, kneeling, and negotiating steps, especially going down the stairs. She may be engaged in strenuous sports, but experiences pain with repeated bending of the knees. Although girls are more often affected, boys can have this problem too.


Possible causes include a tight iliotibial band, neuromas, bursitis, overuse, malalignment, core instability, to name but a few. The term chondromalacia can also be used to describe abnormal appearing cartilage (anywhere in the body)[8]. A radiologist might, for example, note chondromalacia on an MRI of an ankle. There is no one "cause" of chondromalacia. There are as many causes as there are conditions lumped under the term "chondromalacia"


In a sense, whether a child will develop this problem of anterior knee pain and chondromalacia patellae depends on the morphology of the knee and any muscle imbalance she may have. If she is lanky and knock-kneed, she is more likely to develop the condition. If she has tightness of her lateral muscles, she may be more prone to the problem


The treatment will depend on the specific source of a person's pain. Most sportspersons will use variations on the RICE method and anti-inflammatories, to rule out a simple overuse injury. If the pain is very severe or does not pass, they may consult a doctor. As noted above, "chondromalacia" and "patello femoral syndrome" are not diagnoses, as they do not help explain the source of pain. If pain is due to a tight iliotibial band, treatment will be focused on stretching of that band.