Patients have no strength in both legs, commonly due to severe osteoarthritis of both knees, severe lumbar spinal stenosis, and severe cervical spine disease, as follows: First, severe osteoarthritis of both knees: severe osteoarthritis of both knees, especially severe osteoarthritis of the patella, patients will show severe muscle atrophy and muscle weakness in both legs, and tend to have weak legs when walking and fall down easily. Second, severe lumbar spinal stenosis: in patients with severe lumbar spinal stenosis, a herniated lumbar disc will compress the nerves, resulting in nerve damage, loss of innervation of the muscles of both lower limbs, and the patient will also experience significant muscle weakness and even lower limb claudication. Third, serious cervical spine diseases: serious cervical spine diseases, such as cervical spinal stenosis and cervical disc herniation, can also cause nerve dysfunction in the extremities, especially in the bilateral lower extremities, which can manifest as obvious weakness, and the patient can easily fall and be injured. Through timely examination and treatment, most patients with bilateral lower extremity weakness can have their symptoms improved, with limited improvement in severe cases.