Ankylosing spondylitis (AS) is the prototype of spondyloarthropathy, and the available epidemiological data show that the prevalence of AS in China is 0.26%, and hip joint involvement is the most critical lesion in AS that causes disability. Therefore, in the follow-up consultation of AS, both doctors and patients are urged to pay attention to the hip joint lesions. 1, hip lesion is a poor prognosis factor AS is a group of chronic, progressive, disabling diseases, 25% of AS patients involved in the hip joint. Clinical studies have shown that age, gender and hip involvement are important factors in poor prognosis of AS. However, the study by Brophy et al. further confirmed that the real factor affecting the prognosis of AS is damage to the hip joint. They used the statistical method of stratified analysis to correct for interconfounding among the factors. It was found that damage to the hip joint was the factor affecting the prognosis of AS rather than age at onset. This is because in AS without hip damage, there was no significant difference in severity between those with juvenile onset and those with adult onset. However, the rate of hip involvement is significantly higher in juvenile onset AS than in adult onset AS, which explains the poorer prognosis of juvenile onset AS. 2, the characteristics of ankylosing spondylitis hip lesions hip lesions are often insidious, early symptoms are not typical, may be unilateral or bilateral hip intermittent pain, does not attract attention, but tendonitis and synovitis is developing. When there is obvious hip pain or even limited movement, the hip cartilage has been destroyed and the joint space has been narrowed. The pathological changes of AS include tendonitis (tendonitis) and synovitis. In the medial joints of AS, the pathological changes that lead to joint damage and ankylosis are mainly tendonitis. Although AS also often involves peripheral synovial joints (e.g., knees, ankles, etc.), rheumatoid arthritis-like bone erosion is rarely seen, a phenomenon for which there is no definitive scientific explanation. It is believed that osteoclasts play an important role in the pathological changes of RA, as osteolysis is greater than osteogenesis, so obvious bone resorption occurs; in AS, osteogenesis is greater than osteolysis, so it is more likely to form bone fragments. Hip lesions are not yet exactly the same as true peripheral joints. Some scholars believe that the hip joint is neither a medial joint nor a peripheral joint, but is referred to as a root joint. Root joints also include the sternoclavicular joint, shoulder lock, and shoulder. In fact, the hip joint is both a synovial joint and has tendon bone attachment points (garden ligament, etc.). Therefore, the hip joint damage of AS may contain 2 types of pathological changes, namely synovitis and tendonitis. 3, hip lesions are the key to disability In addition to painful symptoms that plague the daily life of AS patients, the most significant damage of AS is the ankylosis of the spine. However, in most cases, simple spinal ankylosis mainly affects the patient’s body shape and leads to inconvenience in activities, and rarely leads to loss of self-care ability. However, the later stages of severe hip damage often lead to severe disability of the patient. Not only is walking difficult, but squatting and sitting are even more difficult, which can result in partial or complete loss of self-care ability. Therefore, in the diagnosis and treatment of AS, attention needs to be paid to understanding whether the patient has hip pain, as well as the frequency, severity and duration of hip pain, in order to determine the extent of hip damage. Since the discipline of rheumatology is not popular enough in China, many AS do not receive reasonable treatment. There are obvious differences in imaging between AS hip lesions and femoral head necrosis, and it is not difficult to distinguish between them in terms of clinical symptoms. In contrast, there is no pain at night in femoral head necrosis, but the pain is obvious during weight-bearing activities, and the passive mobility of the joint is generally not impaired. 4, the hip joint lesions need to strengthen the treatment In summary, the hip joint damage has an important impact on the prognosis and disability of AS. For AS with hip lesions, treatment needs to be more aggressive and treatment modalities to alleviate or control the progression of the disease should be sought. In the author’s limited experience, early and effective control of the inflammatory response is important, and anti-TNF biologics should be recommended as early as possible for patients whose outcomes remain unsatisfactory despite adequate doses of NSAIDs and the addition of disease-relieving antirheumatic drugs. The reason for the need to emphasize early treatment of hip lesions in AS is that early lesions are mild and relatively easy to control, while lesions that develop into chronic synovitis are often less sensitive to drugs and become recalcitrant. Moreover, once cartilage is destroyed, it is often difficult to repair. Therefore, only early and effective control of synovial inflammation can prevent and slow down the destruction of cartilage and bone. For hip lesions of AS, it is not enough to emphasize early treatment, but more important to emphasize effective treatment, i.e. application of drugs with definite efficacy. The author’s experience suggests that anti-TNF biologics should be effective drugs for hip lesions in spondyloarthropathies. In addition, the early treatment of RA has clearly pointed to the early addition of disease-relieving antirheumatic drugs (DMARDs), can the treatment of AS hip lesions also borrow from the treatment model of RA? However, the efficacy of disease-modifying antirheumatic drugs has been controversial in the treatment of AS. One view is that DMARDs do not stop the progression of AS lesions, and treatment of AS emphasizes anti-inflammatory and analgesic therapy, with little or no use of DMARDs; another view is that DMARDs do not stop the progression of AS spinal lesions, but are effective for synovitis and extra-articular damage (inflammatory eye disease) in the peripheral joints of AS patients. 2005, the International Task Force for the Evaluation of AS (ASAS) and the European Anti-Rheumatic Drugs Working Group （In 2005, the International Task Force on AS Evaluation (ASAS) and the European League Against Rheumatism (EULAR) organized 22 experts from 14 countries to analyze and summarize the issues based on their experiences and through a literature search, and finally proposed 10 recommendations for the treatment of AS, of which the eighth recommendation was on DMARDs. it was concluded that there was no evidence that DMARDs, including salazosulfapyridine (SASP) and methotrexate (MTX) are effective for AS with mid-axis joint involvement. SASP treatment can be considered for peripheral arthritis, and no treatment for the hip joint was suggested [4]. Zhao Futao et al. reported the application of MTX for hip lesions in ankylosing spondylitis, with SASP as a control group and 3 years of follow-up, resulting in a significant improvement in functional scores of the hip and CT staging of hip lesions in the treated group compared with the control group. The author’s limited experience suggests that the efficacy of methotrexate, leflunomide and salazosulfapyridine on peripheral joint synovitis is positive. In contrast, they are effective in reducing symptoms in the medial joints in only a minority of patients. The combination of methotrexate-based DMARDs is also efficacious for pain and synovial inflammation in the AS hip joint. Biologic tumor necrosis factor-a (TNF-a) antagonists have been accepted internationally by a wide range of rheumatologists. TNF-a antagonists that have been marketed in China include etanercept, a TNF-a receptor-antibody fusion protein, and infliximab, a monoclonal antibody to TNF-a. A European epidemiological follow-up study involving 89 rheumatologists and 2,141 cases of AS showed that treatment with TNF-a antagonists was recommended in about 40% of AS, with dosing based on the activity and severity of the disease. A survey involving rheumatologists from 10 countries showed that about half of the patients with AS were considered to be treated with TNF-a antagonists, with Canadian physicians considering 37.2% of AS patients to be treated with TNF-a antagonists, while Australian physicians advocated the use of TNF-a antagonists in 78.3% of AS patients [7]. A group of follow-up studies in the UK showed that both etanercept and infliximab had rapid and sustained efficacy in the treatment of AS and that hormone therapy could be stopped in more than half of those treated. A 4-year follow-up study of infliximab for AS in Germany initially showed that this TNF-a antagonist treatment delayed and modified bone damage. Although the clinical future of TNF-a antagonist therapy for AS remains to be determined in longer follow-up studies, the combination of methotrexate and TNF-a antagonist therapy can alleviate the inflammation of AS, especially synovitis and tendonitis of the hip joint, in a relatively short period of time, and does have value in preventing further damage to the hip joint. The high incidence and disabling nature of hip lesions in ankylosing spondyloarthritis should receive further attention. Only if everyone recognizes the seriousness of the lesion and actively takes effective treatment measures can the disability rate of AS be reduced.