Ankylosing spondylitis, if left untreated, generally takes 5-10 years to become disabling because the early stages of ankylosing spondylitis are slow to develop and progress slowly, usually from the sacrococcygeal to the lumbar and thoracic spine and then to the cervical spine in parallel, with bamboo-like changes, and this gradual change takes 5-10 years, which is a long time. The so-called disability of ankylosing spondylitis can cause the fusion of deformities in the spine and the fusion of joints outside the spine, such as the hip and shoulder joints, especially the hip joint, and the ankylosis of the hip joint means the loss of function of the hip joint, so ankylosing spondylitis takes 5-10 years to become disabled, and can cause ankylosis of the spine or joints.