Patellar chondromalacia is an osteoarthrosis of the patellofemoral joint formed when the cartilage surface of the patella is swollen, cracked, broken, eroded, and dislodged due to chronic injury, and finally the cartilage of the femoral condyle opposite to it also undergoes the same pathological changes. Common causes are 1, congenital patellar developmental disorder, abnormal position, femoral condyle anomaly; or acquired knee inversion, tibial external rotation deformity, etc., can make the patella unstable and become the basis for chronic injury. 2, long-term, rapid, forceful flexion and extension of the knee joint, increasing the wear and tear of the patellofemoral joint. 3, various reasons for abnormal synovial fluid composition, can make the patellar cartilage malnutrition, vulnerable to minor injuries and degenerative changes. The most common manifestations are knee pain when walking upstairs and uphill, pain and friction sounds behind the patella when pressing and rubbing the patella, once diagnosed by a doctor as chondromalacia patellae, most of them need conservative treatment. Conservative treatment: First, avoid climbing stairs and hills and other sports. Second, it is important to strengthen the functional exercise of the quadriceps muscle to increase the stability of the knee joint. Third, intra-articular vitreous acid injection is very controversial, some people think it does not work, some people think it does, depending on your situation. It is best not to inject hormones into the joint that interfere with cartilage metabolism. Oral chondroitin sulfate may have some effect. It is important to strengthen the functional exercise of the quadriceps muscle, and must be adhered to. 1, the patient’s legs apart, the distance between the two feet is slightly wider than the shoulders, the body remains upright position, can not lean forward, then the knees began to bend squat. 2, both knees bending angle according to the patient’s physical condition and muscle strength and different. If the patient’s physical condition is good, good thigh strength, squatting can reach 90 degrees of knee flexion, if the patient is weak, weak thigh muscle strength, both knees can be lightly flexed, this time the half squat position is higher, the patient more effort, can be later with the exercise, the thigh muscle strength increases, and then increase the angle of knee flexion. 3, each patient in the squat will have a painful angle, some squat to 30 degrees pain, some squat to 60 degrees, or 40 degrees pain, practice static squat best to avoid the pain angle, if squat to 30 degrees pain, you can continue to squat down to 60 degrees to avoid the 30 degrees of pain angle, and vice versa. 4, a squat duration each person varies greatly, are squatting until you can not hold on. Rest a minute between two squats, do not rest too long. Then practice the second squat, so that week after week, 30 minutes in a row for the day of a squat exercise. According to their own physical condition to determine the number of exercises, practice 1-3 times a day.