Chondromalacia patella may be caused by congenital developmental factors, overloading of the knee joint and joint malnutrition. 1. Congenital developmental factors: it may be due to abnormal joint anatomy, such as congenital patellar developmental disorders or abnormal developmental position, which may lead to patellar chondromalacia, and it is easy to form chronic injury. 2. Knee overload: for example, excessive obesity or engaging in long-term sports with heavy joint load will easily lead to chondromalacia patella. 3. Joint malnutrition: the nutrition of patellar cartilage mainly comes from the synovial fluid in the joint cavity, if the joint is malnourished, it will not be able to get enough nutrition, resulting in chronic injury, leading to chondromalacia patella. Chondromalacia patella may also be caused by rheumatoid arthritis, peripatellar synovitis, etc. It is recommended to consult a doctor in time to find out the cause of the problem and then target treatment or therapy.