Knee disorders usually present with pain in or around the knee. So, when there is pain in or around the knee, could it all be a knee disorder? In recent years, we have focused on the diagnosis and treatment of knee disorders and have seen more patients with knee disorders, but several patients with knee pain have been diagnosed by doctors as not having knee disorders, but as early stage femoral head necrosis! Why is this? Femoral head necrosis is a bone and joint disease that causes ischemia of the femoral head, structural changes, femoral head collapse, and joint dysfunction due to microcirculatory disorders of the femoral head. However, about 30-40% of patients present early not with hip discomfort, but with medial knee pain. Half a month ago, I met a patient who reported pain above the knee. Upon examination of the knee, there were no pressure points and nothing else abnormal, so I suspected that it was a disease of the hip joint and asked him to take a film of the hip joint. The patient was upset and said that he was obviously having knee pain, so why did he go for a hip radiograph? After repeated explanations from the doctor, the patient reluctantly went to have the film taken. The results came out very quickly: necrosis of the femoral head with multiple cystic lesions! Especially in older patients, in this case, many patients will think nothing of it and treat the pain as arthritic pain, when in fact it may be a problem with the femoral head. There was a patient who had been treated for a long time for pain above the knee in many hospitals in many places according to knee disease, but it never worked, and finally came to me in the provincial capital and was diagnosed by me with middle stage femoral head necrosis with mild collapse of the joint surface. Here I will give you the answer to this question. To put it simply, this situation is mainly the result of nerve conduction. There are two groups of nerves around the hip joint, the femoral nerve in front and the foraminal nerve on the inside. The femoral nerve originates from the lumbar 2 to lumbar 4 spinal nerve, which is a large branch of the lumbar plexus and travels down between the psoas major muscle and the iliopsoas muscle, travels under the inguinal ligament, enters the femoral triangle on the lateral side of the femoral artery, and then branches out to innervate the quadriceps and suture muscles and the skin on the front of the thigh. The obturator nerve originates from the lumbar 2 to lumbar 4 spinal nerves, and is divided into a muscular branch and a cutaneous branch at the root of the thigh. The muscular branch mainly innervates the internal thigh muscles, while the cutaneous branch is mainly located in the skin of the lower medial thigh. Since the femoral and foramen ovale nerves innervate both the hip and knee joints, when the hip joint is diseased, the nerve can be stimulated and pain in the inner thigh and knee can occur through the reflex action of the same spinal cord segment, and sometimes low back pain may also occur. Therefore, it is recommended that when symptoms of knee pain occur, you must seek medical attention in a timely manner to avoid aggravation of the condition.