Chondromalacia patellae (also known as CMP) is a term that goes back eighty years. It originally meant "soft cartilage under the knee cap," a presumed cause of pain at the front of the knee. This condition often affects young, otherwise healthy athletes. Chondromalacia is due to an irritation of the undersurface of the kneecap. The undersurface of the kneecap, or patella, is covered with a layer of smooth cartilage. This cartilage normally glides effortlessly across the knee during bending of the joint. However, in some individuals, the kneecap tends to rub against one side of the knee joint, and the cartilage surface become irritated, and knee pain is the result...