The two knees are weak and sore mainly due to the following diseases: 1, bilateral degenerative knee disease, for example, some elderly patients will have knee osteophytes, bone spur formation, bilateral knee degenerative disease, mainly manifested as bilateral knee soreness and weakness when active, relieved after rest. 2, to ask the patient whether there is bilateral lower limb numbness, if the bilateral knee is symmetrical appearance, to If the patient has bilateral knee weakness with numbness of the limbs and weakness of the hands, consider that the patient may have demyelinating disease, such as Green-Barre syndrome, and also need to do electromyography and lumbar puncture, cranial lumbar MRI examination.