Much of the prepatellar pain is a secondary lesion of patellofemoral dysplasia. The abnormal patellar trajectory or force line is due to abnormal patellofemoral activity during knee flexion, which generates abnormal shear stresses that are transmitted to the subchondral bone, and the long-term, continuous and repeated deformation causes premature chondral cartilage softening and fissures in the patellofemoral joint, eventually leading to osteoarthritis of the patellofemoral joint, which is incorrectly described by osteochondritis of the knee joint alone. The causes of early onset of prepatellar pain with abnormal patellar trajectory and force lines are: (1) excessive loading of the lateral patellar bone surface; (2) excessive tension in the lateral patellar ligament, which produces degenerative or neuroma changes in the nerves within the lateral support band. Poor patellar trajectory or abnormal force lines include: (1) lateral patellar compression syndrome; (2) chronic patellar subluxation; and (3) recurrent patellar dislocation. Accurate diagnosis and proper treatment are key to the rehabilitation of this injury. These diseases can be treated conservatively for 2-3 months in early stages, with few symptoms and a short duration. Those with good results continue, and those with poor results need to undergo surgery. 1.Tui-na: turning the patella inward and pushing the patella inward to loosen the lateral over-tightened support band and relieve the pressure on the lateral small joint of the patellofemoral joint. 2.Physical therapy: transcutaneous electrical stimulation of the medial femoral muscle to promote muscle recovery. 3, physical therapy: medial femoral muscle strength training: is the most important step to overcome prepatellar pain, and strengthening the trained medial femoral muscle has a significant effect on correcting poor patellar force lines. ①The rectus femoris and medial femoral muscle exercise method: lower limb external rotation, ankle weight-bearing, starting from 1 kg (can be increased or decreased according to the patient’s condition), up to 7.5 kg. Leg lifts are performed in sets of 5~10 times, each time in sets of 5~10. The exercises can be practiced every other day at first, and the condyles are practiced daily after muscle strength is strengthened. ②Lateral iliac fascia stretching, high seat fixed bicycle exercises, double feet placed in the “inner eight” heel lift, half squat “horse stance” exercises, balance board exercises, etc.. These should be practiced under the guidance of a doctor. 4, tape fixation patella method: for early patients can improve the symptoms. The tape fixation can slightly improve the patella trajectory when the knee joint is extended and flexed, but only temporarily. The disadvantage is that the tape is easy to cause skin allergy when it is in contact with the skin for a long time. Therefore, tape is applied during the day at school and work and removed at night after school or work. The tape fixation method needs to be directed by a doctor. 5, brace protection: there are a variety of patella track brace. The effect is the same as tape, which is also temporary, avoids tape allergy and is easy for the patient to grasp.