Background Previous studies showed that patients with coxitis have higher disease activity and more pronounced functional impairments. Following these findings early detection of coxitis is of great clinical importance.
Objectives To study the incidence of HJ involvement in patients with early spondyloarthritis (SpA).
Methods The study included 130 patients (mean age 28,7±7,5 y): 77 (59,2%) with axial SpA (axSpA, ASAS 2009) and 53 (40,8%) with peripheral SpA (pSpA, ASAS 2011), 56,9% – females, 83,7% - HLAB27-positive. Average disease duration in axSpA was 19,7±14,8 mo, in pSpA – 8,9±8,8 mo. The following evaluations were made: BASDAI, ASDAS-CRP, ASDAS-ESR, BASFI, HJ pain (numerical rating scale – NRS - from 0 to 10), inter-malleolar distance (IMD), radiological HJ changes (BASRIhip), ultrasound examination (US) and MRI of hip joints.
Results 74 (56,9%) out of 130 patients suffered pain in HJ (the majority of them (73%) met axial SpA criteria). 67,6% out of 74 patients had pain in the right HJ, 85,1% - in the left HJ, while 52,7% - had pain in both HJ. Mean pain score in the right HJ was 5,5±7,8, in the left HJ – 4,6±6,0. Mean duration of HJ pain was 9,1±10,9 mo. HJ funcional limitations were documented in 27 patients (36,5%), bilateral were found in 66,7%. IMD was 90,4±15,5 cm. Functional limitations lasted for 8,7±9,4 mo in average. HJ radiological changes were documented in 20 (27,0%) out of 74 patients: in 9 cases - BASRIhip =2, in 11 cases – BASRIhip=1. US symptoms of coxitis (the distance between the anterior joint capsule and the femoral neck, capsular-neck distance CND >7 mm) were found in 32 joints (on the right – 14 (CND 8,4±5,9 mm), on the left – 18 (8,3±1,5 mm)). Inflammatory MRI symptoms were found in 41 joints (on the right – 20 (swelling of bone marrow in femoral head – 3, swelling of acetabular roof – 5, synovitis – 20), on the left – 21 (swelling of bone marrow in femoral head – 6, swelling of acetabular roof – 7, synovitis – 21). Patients with early SpA and HJ involvement had higher disease activity vs patients without HJ involvement (BASDAI (4,3±2,1 vs 3,2±1,8), ASDAS-CRP (2,8±1,3 vs 1,8±1,2), ASDAS-ESR (2,7±1,4 vs 1,9±1,4)), although without any difference in functional impairment by BASFI.
Conclusions 1. HJ involvement is more common in patients with axSpA.Pain and functional limitation in HJ in early SpA patients were found in 56,9% and 36,5% cases, respectively, and they were bilateral in the majority of cases. Radiological changes were found in 27,0% of cases despite short-standing HJ pain in the studied sample.US and MRI changes were found in 32 and 41 HJs, respectively. Patients with HJ involvement demonstrated higher disease activity as compared to SpA patients without HJ involvement. 2. Further studies are warranted to gain better insight into HJ involvement in early SpA to identify potential predictors of radiological progression and role instrumental modalities in early detection of coxitis.
Disclosure of Interest None declared