Combined femoral and acetabular version and synovitis are associated with dGEMRIC scores in people with femoroacetabular impingement (FAI) syndrome.

This study sought to explore, in people with symptoms, signs and imaging findings of femoroacetabular impingement (FAI syndrome), (1) whether more severe labral damage, synovitis, bone marrow lesions or subchondral cysts assessed on MRI were associated with poorer cartilage health, and (2) whether abnormal femoral, acetabular, and/or combined femoral and acetabular versions were associated with poorer cartilage health. This cross-sectional study used baseline data from the 50 participants with FAI syndrome in the Australian FASHIoN trial (ACTRN12615001177549) with available dGEMRIC scans. Cartilage health was measured using delayed Gadolinium-Enhanced MRI of cartilage (dGEMRIC) score sampled at the chondrolabral junction on three mid-sagittal slices, at one acetabular and one femoral head region of interest on each slice, and MRI features were assessed using the Hip Osteoarthritis MRI Score (HOAMS). Analyses were adjusted for alpha angle and BMI, which are known to affect dGEMRIC score. Linear regression assessed the relationship with dGEMRIC score of i) selected MRI features, and (ii) femoral, acetabular, and combined femoral and acetabular versions. Hips with more severe synovitis had worse dGEMRIC score (partial eta-squared=0.167, p=0.020), whereas other MRI features were not associated. Lower combined femoral and acetabular version was associated with better dGEMRIC score (partial eta-squared=0.164, p=0.021), whereas isolated measures of femoral and acetabular version were not associated. In conclusion, worse synovitis was associated with poorer cartilage health, suggesting synovium and cartilage may be linked in the pathogenesis of FAI syndrome. Lower combined femoral and acetabular version appears to be protective of cartilage health at the chondrolabral junction. This article is protected by copyright. All rights reserved.