This term can be a general term for general knee pain.  Usually this pain is caused by excessive pronation or arch collapse.  As the foot rolls inward the shin bone rotates internally causing the knee joint to skew placing extreme pressure at this point.  As this takes place the body tries to compensate and excessive forces are applied to the patella or knee cap.

Excressive strain on the knee over long periods of time can cause a grinding in the knee which is often accompanied by sharp pain.