| Objective: To observe osseous acetabular anteversion(OAA)and cartilaginous acetabular anteversion(CAA)with different ages using MRI and analyze its development and growth.And observe these changes of OAA and CAA in children with developmental dysplasia of the hip(DDH).Methods: We retrospectively analyzed the medical records of children who underwent hip MRI examination at our hospital from January 2008 to January 2018.293 children with normal development of the hips were as normal controls,including 147 boys and 146 girls with a mean age of 8.01 years(range,1 month to 16 years).Additionally,196 patients with DDH were reviewed in this study,including 159 girls and 37 boys with an average age of 34.3 years(range 6 to 84 months).In all,151 children were unilateral involved(95 left hips,56 right hips)and 45 children bilateral involved.All the involved hips were classified by IHDI(International Hip Dysplasia Institute)classification.The OAA and CAA were measured on the cross sections on MRI,and the developmental patterns of the both in normal were determined by age-based cross-sectional analysis.The differences of OAA and CAA in normal and DDH children were compared.The data were statistically analyzed.Results: The normal OAA unremitting ascending from mean 8.69°±3.16° to 11.83°±2.95° during the first two years postnatal.After this,it maintained unchanging until 9 years.From 9 to 16 years,the OAA revealed a little increase of 2°-3 ° again.The mean OAA was increasing to 14.37°±3.55° at the age of 16 years.The normal CAA increased rapidly from mean 12.29°±3.13° to 15.19°±2.68° within the first two years of life,and then maintained at a constant level of 15.17°±3.38° until 16 years.For normal children,There was no significant correlation between normal OAA,CAA and laterality(P=0.224 and P=0.574),there was also a correlation between OAA and CAA(r=0.916,P<0.001).The average OAA and CAA of DDH with involved hips were 17.14°(SD 4.19°)and 22.65°(SD 4.49°).No significant difference in OAA and CAA was found among the IHDI types,except for the minimal difference(approximately 2°-3°)between type I and IV(P=0.021),type II and IV(P<0.001)for OAA;and between type III and IV(P=0.012),type II and IV(P<0.001)for CAA.Likewise,the OAA of the uninvolved hips in unilateral DDH was 14.43°±3.50°,and the normal hips was 11.32°±3.15°(P<0.001);the CAA of the uninvolved hips in unilateral DDH was 18.37°±3.67°,and the normal hips was14.57°±3.03°(P<0.001).Conclusions: The normal CAA has fully formed at birth,and maintains constant until adulthood.The osseous and cartilaginous acetabulum were both overanteversion in DDH children.Both OAA and CAA in the unaffected hips in unilateral DDH are also mildly dysplastic.In childhood,the osseous anteversion does not represent cartilaginous anteversion,MRI is necessary when assessing acetabular cartilage components and performing hip surgery. |
PDF Full Text Request