Ankylosing spondylitis occurs in older children, generally peaking at 12-16 years of age, and the lesions develop rapidly. Once the lesions appear to destroy the hip joint, medication can relieve painful symptoms, but it is no longer possible to reverse the destroyed bone structure, and functional impairment is inevitable. Ankylosing spondylitis is common in younger patients and is often accompanied by disuse osteoporosis in those with ankylosing hip joints. These two features were previously considered contraindications to artificial joints, making many scholars cautious about the treatment of ankylosing spondylitis with total hip replacement. Chandler believes that total hip replacement should not be performed until 20 years after the onset of ankylosing spondylitis, when hematocrit and C-reactive protein are as normal as possible. Because the hematocrit and C-reactive protein are under control at this time, the chance of hip pain and ankylosis after surgery is reduced. However, patients with ankylosing spondylitis with ankylosing deformity of the hip are mostly between the ages of 20 and 45, which is the most important period in their lives. A successful joint replacement can enable the patient to return to normal life and work, instead of postponing the time of surgery. When the hip joint is in a non-functional position for a long time, the muscles and bones around the joint often undergo disuse atrophy and laxity, and the longer the period of time, the more serious it is, which greatly increases the difficulty of future surgery and the risk of failure. Therefore, there is no need to make patients with ankylosing spondylitis hip ankylosis endure great pain to wait for the optimal age for total artificial hip replacement. Most scholars now believe that the age of onset of this disease is generally young, and the earlier the onset, the more severe the symptoms, and the greater the need for early surgical treatment. The authors believe that age should not be a limitation for implementation in patients with ankylosing spondylitis of the hip joint. Artificial total hip replacement can be performed when the hip joint becomes stiff and painful and regular drug treatment is ineffective or the efficacy is uncertain, bone development has matured, symptoms continue to worsen, and the quality of life of the patient has been seriously affected, so that the patient can resume normal life and work as soon as possible.