Also known as patellofemoral strain and chondromalacia patellae, a common and prevalent disease of the knee joint. How does this disease occur? The patellofemoral joint is damaged by prolonged and violent friction between the patellofemoral joints. The medial and lateral femoral condyles form a sagittal shallow concavity —- on the patellofemoral joint surface, which is the intercondylar groove. When the knee joint is fully flexed, the patellofemoral joint surface presses against the sagittal shallow concavity in front, forming a near parabolic trajectory of the patella, and the patella increases about 2.5 times the knee joint The force arm reduces the force on the joint. Softening of the patella leads to pain because the force arm becomes shorter and the force in the joint increases, with a high prevalence in middle-aged and elderly people, but in recent years the prevalence has increased year by year among young people with the popularity of sports and fitness, especially among athletes in track and field and professional mountaineers. The disease also occurs after strenuous exercise, such as climbing, dancing, and repeated squatting. The clinical manifestations are hidden pain and weakness in the knee, especially when the pain is obvious when force is exerted, and the legs feel weak when going up and down stairs, which seriously affects walking. The “patella test” is performed by pushing the patella distally when the knee is straightened and asking the patient to contract the quadriceps muscle, which is positive for patellofemoral pain. The first treatment is to wear a knee brace and brake to rest; Chinese medicine is suitable for activating blood and warming the meridian to relieve pain, such as the adult medicine Xiaohuiluo Dan, decoction of stretching tendon grass, millennium health and other medicinal baths or fumigation and external washing, hot amniotic package, teng medicine; Western medicine oral glucose and bone; ultrashort wave physiotherapy; rehabilitation exercises for static squatting to enhance the strength of the quadriceps muscle. Generally speaking, it will be healed. If not relieved, patellar axial film, semi-dislocation, surgical treatment.