Su yeon Hwang, Presenter: Nothing to Disclose

Jung-Ah Choi MD, Abstract Co-Author: Nothing to Disclose

Koungmi Kang, Abstract Co-Author: Nothing to Disclose

Young Kyun Lee, Abstract Co-Author: Nothing to Disclose

Yong-Chan Ha, Abstract Co-Author: Nothing to Disclose

Heung Sik Kang MD, Abstract Co-Author: Nothing to Disclose

Ji Hang Kim MD, Abstract Co-Author: Nothing to Disclose

To retrospectively evaluate if there is an increased prevalence of juxta-articular fibrocystic changes at the femoral head and neck in hips with femoroacetabular impingement (FAI), as compared with hips without FAI, and to analyze their characteristics.

Two radiologists in consensus retrospectively reviewed 3D computed tomography (CT) arthrography of 82 hips with FAI (39 cam, 31 pincer, 11 combined types) and compared these images with 3D hip CTs of a sex-and age-matched control group of 82 hips without FAI. Exclusion criteria for control group were hip dysplasia, previous hip surgery, advanced hip OA, metastasis, avascular necrosis and fracture in the corresponding hip. Criteria for juxtaarticular fibrocystic changes at the femur head and neck were location close to the physis, either the head, neck, or transitional zone, and a diameter of greater than 2mm with sclerotic margin. The presence, size, and location of the fibrocystic changes were analyzed. Alpha angles were measured on oblique-axial images. Chi-square test and student t test were used for statistical analysis.  

Fibrocystic changes were identified on the CT arthrography of 38 (46.3%) of the 82 FAI-affected hips and on 17 (20.7%) of 82 the hip CTs of the 82 control hips (p = 0.000). Among the three FAI types, only cam type FAI showed a significantly increased prevalence of fibrocystic change compared with that of the control group (p=0.000). Alpha angle was not significantly different between hips with [mean 57.8 (range, 47.2-69.9)] and without fibrocystic change [mean 61.5 (range, 54.8-71)] (p= 0.03). Fibrocystic changes were predominantly found in the superior portions of the proximal anterior femur neck in both groups (FAI group: 31 of 38, 81.6%/ control group: 14 of 18, 77.8%). The mean diameter of the juxta-articular fibrocystic changes was 6.0 mm (range, 2.4–12.3 mm) in the FAI group vs. 5.5 mm (range, 2.7-11.0 mm) in the non-FAI group.

Juxta-articular fibrocystic changes in the proximal femur head and neck were significantly more prevalent in hips with FAI, especially cam type, as compared with hips without FAI. The presence of fibrocystic changes in the proximal femur may signify the presence of FAI, especially cam type.  

The presence of fibrocystic changes in the proximal femur may signify the presence of FAI, especially cam type.

Hwang, S, Choi, J, Kang, K, Lee, Y, Ha, Y, Kang, H, Kim, J, Are Fibrocystic Changes at Femoral Head and Neck Truly More Common in Hips with Femoroacetabular Impingement (FAI)? 3D CT Assessment in Hips with FAI vs Hips without FAI.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12029439.html