By the time a patient develops even moderate hip pain, the destructions are usually extensive ( 12). Very few imaging studies have been done with the aim of identifying early hip lesions. As a whole, hip lesions may be more severe in patients with early age onset, highly active axial, and entheseal diseases ( 14, 15). Hip lesions have been reported in 25 to 35 percent of AS patients ( 12, 13). Such studies need markers that might identify early hip disease. However, prevention of progression has not been studied for hip destruction. It is commonly thought that early treatment can prevent syndesmophyte formation ( 10, 11). Not all patients develop syndesmophytes or hip destruction ( 9). The disease activity in many patients can be controlled by a TNF inhibitor, an IL-17 inhibitor, or a Janus kinase inhibitor ( 4, 7, 8). Other than pain, the two most common disabling features are bridging of vertebral syndesmophytes and hip destruction ( 4– 6). In the majority of ethnic groups, many AS patients carry the HLA-B27 gene ( 1– 3). Radiographic sacroiliitis is present in AS but not in nr-axSpA ( 1). At least 40% of AS patients with minimal or no hip pain might already show MRI and X-ray changes.Īxial spondyloarthritis consists of two groups of entities, ankylosing spondylitis (AS), also known as radiographic axial spondyloarthritis, and non-radiographic axial spondyloarthritis (nr-axSpA). In these latter patients, functional activities of the hips such as walking were normal. Based on the normal hip width of HC, joint space narrowing was observed in 94.3% of the entire AS cohort, and importantly 56.7% of AS patients with no or mild hip pain. Parallel finding that X-ray changes were present in patients with minimal or no hip pain was also observed with X-ray. These lesions in AS were observed singly or in combination in the trochanters (8%), femoral heads (12%), and acetabula (13%). This was much more frequent compared to the 2% in HC (p < 0.05). Most importantly, 42% of AS with no or minimal hip pain had one or more MRI lesions. In MRI images, BME lesions in the STIR sequence were much more frequent in AS (62%) compared to HC (2%) (p < 0.0001). Forty-four patients with early hip osteoarthritis (OA) served as positive imaging controls. Clinical and imaging hip data were systematically analyzed in 200 healthy controls (HC) and 300 AS with varying degrees of hip pain. To examine if AS patients whose hip pain is either absent or minimal might already have observable MRI and X-ray hip changes. Therefore, the key to improve the prognosis of AS is the early diagnosis of hip injury. 3Rheumazentrum Ruhrgebiet Herne, Ruhr-University Bochum, Herne, GermanyĪnkylosing spondylitis (AS) is most common in adolescents and the ultimate result is disability, which places a huge burden on patients and society.2National Translational Science Center for Molecular Medicine, Xi’an, China.

1Department of Clinical Immunology, PLA Specialized Research Institute of Rheumatology & Immunology, Xijing Hospital, Fourth Military Medical University, Xi’an, China.Qing Han 1 Zhaohui Zheng 1,2 Kui Zhang 1,2 Jin Ding 1,2 Xenofon Baraliakos 3 Ping Zhu 1,2*

Normal hip joint xray