Magnetic resonance imaging study of acetabulum in developmental dislocation of the hip for children

Abstract

Objective To explore the diagnostic value and severity assessment of magnetic resonance imaging (MRI) in acetabulum of developmental dislocation of the hip (DDH) for children at different ages. Methods Between January 2010 and January 2015, a total of 76 unilateral DDH cases of hip MRI data were retrospectively analyzed.Affected hips were included into patient group while normal hips served as control group.Infant group was aged under 1 year (n=14), young children group 1-3 years (n=38) and children group 4-13 years (n=24). Bony and cartilaginous hip parameters of all hips, including depth of acetabulum, bony acetabular index (BAI) and cartilaginous acetabular index (CAI), were measured in T1W1 sequence on coronal MRI.And the distribution of acetabular cartilage was measured simultaneously in all groups. Results Depth of acetabulum was (5.54±2.32) mm and (9.32±2.91) mm, BAI was (33.65±5.08) and (23.12±5.28) and CAI was (20.86±6.38) and (12.81±4.71) in patient and control groups respectively.Differences in depth of acetabulum, BAI and CAI existed between patient and control groups.And three indices except for CAI for three age groups were statistically significant (P<0.05). A liner correlation existed between BAI and CAI in patient and control groups and separate three age groups (r=0.74, 0.88, 0.70, 0.66, P<0.05). The distribution of acetabular cartilage in anterosuperior, top and posterosuperior side was abnormal and difference was statistically significant in children aged over 1 year (P<0.05). Conclusions MRI is an effective imaging modality for assessing bony and cartilaginous structures.And it provides important rationales for assessing the developmental status of acetabulum in DDH. Key words: Developmental dislocation of the hip; Magnetic resonance imaging; Acetabulum