Chondromalacia is caused by an irritation of the underside of the kneecap. It can occur by simple wear and tear on the knee joint or arthritis as we age. In young exercisers, however, it is most likely due to an acute injury such as a fall, overuse, problems with knee alignment, or even muscle weakness.
The underside of the kneecap, and the top of the thigh bone (femur) are both covered with a smooth and slippery (articular) cartilage that allows these two bones to slide easily over one another when the knee flexes. If this cartilage is damaged, the surface becomes rough and gets irritated with movement. Damage can be minor or severe, and may result in varying degrees of pain.
The most common symptom of chondromalacia is a dull pain under or around the kneecap that increases while walking down stairs. There may also be pain with stair climbing or getting out of a chair, etc. This injury is common in runners, skiers, cyclists, and soccer players.
The best treatment for chondromalacia is low-impact exercise that strengthen muscles (focused the inner part of the quadriceps) and avoiding jumping or impact exercise as much as possible. Swimming, stationary bicycle, and cross-country skiing are good ways to strengthen the joint without impact. It's helpful to avoid any activity that requires the knee to flex more than 90 degrees.
Finally, arthroscopic surgery may be used to smooth the surface of the articular cartilage and clean out cartilage fragments that cause the joint to catch during bending and straightening. This determination can only be made by a proper evaluation and diagnosis, so always see your doctor for knee pain that lasts more than two weeks.