Imaging Studies In Acetabular Anteversion Of Developmental Dysplasia Of The Hip

Objective：The osseous and cartilaginous acetabular anteversion were respect-tively measured in the DDH and normal control individuals using3D-CT and MRI.To observe whether the acetabular anteversion (AA) on the basis of3D-CTmeasurement is positive correlation with the AA on the basis of MRI measurement,and whether the AA on the basis of CT measurement could reflect the true AA. Toobserve the CAA in normal children with different ages and analyze its developmentand growth.Methods：55CT and MRI images of DDH patients with an average age of19months (range6to60months) and30CT images of normal control individuals witha mean age of20months (range7to60months) and222MRI images of normalcontrol individuals with a mean age of6.2years (range from3month to15years)were involved in the study. The osseous and cartilaginous acetabular anteversion wererespectively measured in the DDH and normal control individuals using3D-CT andMRI. The data were statistically analyzed.Results：Cartilaginous AA on the dislocated and subluxated hips in DDH basedon MRI measurement is also larger than that on the unaffected hips (P <0.05).Positive correlation was observed between the CT-based AA and the MR-based AAin DDH (P <0.05). However, the3D-CT-based AA was smaller than the MRI-basedAA (true AA) in DDH (P <0.05). The correlation of cartilaginous AA with the agewas not presented in the normal group using the MRI evaluation (P>0.05). Noneretroverted acetabulum was found in the DDH group and the normal control groupon the basis of CT and MRI measurement.Conclusion：Like the osseous AA, the cartilaginous AA was also significantincreasing on the dislocated and subluxated hips in DDH. Moreover,3D-CT basedAA was positive correlation with MRI based AA in DDH. However, it is notable thatosseous AA on the basis of3D-CT measurement is smaller than true AA(cartilaginous AA) on the basis of MRI measurement. The normal cartilaginous AA has fully formed at birth, and there was not obvious fluctuation at different agegroups. None retroverted acetabulum was found in the children with DDH and thenormal control individuals using MRI and3D-CT evaluation. MRI images of DDHcould better reflect the true morphological abnorm-alities, and were fairly importantin guiding the right type of surgical procedure for surgeons in DDH.