Chondromalacia of the patella

Chondromalacia of the patella is the grating or grinding sensation during extension of the knee. The cause is thought to be related to overuse, trauma and/or abnormal forces on the knee, such as a mildly abnormal alignment of the patella (knee cap) and femur. Symptoms include knee tenderness, pain in the knee after sitting for a prolonged period of time, knee pain that is worse with stairs or getting out of a chair, and a grating sensation in the knee.