This disease is more common in children, and more common in women than in men. Traumatic patellar dislocation combined with lateral femoral condyle fracture is mostly caused by improper treatment. Most of the patients have abnormal development of the local structure of the knee joint, which is caused by minor trauma. Those with abnormal development of the local structure have contracture of the lateral soft tissue of the knee; the attachment point of the patellar ligament is biased to the outside; the insertion point of the vastus lateralis muscle is abnormal; the patella is small and flat; the intercondylar notch of the femur is shallow and the lateral condyle is dysplastic; and the knee is valgus deformed.