When numbness occurs inside the knee, it is important to consider whether the nerves around the knee are abnormal, or whether other pathologies are pressing on the nerves, causing numbness in the knee. It is common for the closed nerve to be irritated, causing numbness in the knee, and some patients are in the early stages of hip lesions. In some patients with early stage femoral head necrosis, the location of the lesion stimulates the surrounding foraminal nerve, causing numbness in the knee joint. But usually there can be no other symptoms manifested, and as the local symptoms worsen, the symptoms of numbness in the knee joint will be relieved. Other patients with irritation of the sciatic nerve, such as lumbar transverse spine syndrome, can also experience numbness in the knee joint, but pain in the lower back.