Research On The Acetabular Morphological Assessment For Developmental Dysplasia Of The Hip In Adults By3DCT And Computer Assisted Surgical Simulation

Background:Developmental dysplasia of the hip is regarded as a common causeof early limited mobility and secondary hip osteoarthritis, whose early-stage diagnosisand radiographic assessments are of great significance in anatomical abnormalityrecognization and therapeutic opinions. Due to the complex acetabular pathoanatomy,the evolution of acetabular morphology changes of adults developmental dysplasia ofthe hip contributes to the improvement of diagnosis, preoperative design andtherapeutic evaluation.Objective:To analyze the anatomical acetabulum among adults withdevelopmental dysplasia of the hip by utilizing the three dimensional computedtomography and computer assisted surgical simulation. Assessments of the acetabularmorphology changes and bone stock leads to guiding operation and implants optimaldesign.Methods:From January2010to December2014,54patients with80hips(13hipsof10male cases,67hips of44female cases) were diagnosed as acetabular dysplasiaby center-edge angle and scanned with CT. According to the Crowe classification,there were33hips of Crowe type I,14hips of Crowe type II,14hips of Crowe typeIII and19hips of Crowe type IV. Through standard hip3DCT reconstruction, frontalpelvic plane is defined to correct the pelvic position.3D pre-operative was performedusing Mimics stimulation and a computer-aided design format planning to predict theacetabular component size, hip rotation center position and acetabular componentcoverage. Thus, the true acetabulum and rotation center were determined byimplanted components. Firstly, the bone stock of anterior and posterior columns ofacetabular was observed and acetabular anteversion, CE angle, SHARP angle andmedial wall thickness were measured. Secondly, the anterior and posterior acetabularsector angles in the axial plane passing through the center of the femoral head were measured, as well as ASAs in the anterosuperior, superior and posterosuperiordirection. Finally, the3D cup coverage was also measured by utilizing the stimulationmodule.Results:With Crowe type increased, acetabular anteversion, CE angle and cupcoverage gradually increased with significant positive correlation. By contrast,SHARP angle, medial wall thickness decreased with significant negative correlation.In the meantime, among indices of the acetabular coverage, AASA decreasedgradually and the others increased significantly. Furthermore, all the measure indiceshad a statistically relevant with the cup coverage except the AASA and medial wallthickness.Conclusion:Firstly, three dimensional computed tomography reconstructionappears to have prominent advantages in displaying the morphology andpathoantomical structure of dysplastic hips comprehensively and accurately. Secondly,Adult acetabular morphology changes between different Crowe types in patients withdevelopmental dysplasia of the hip. Thirdly, the notion of effective bone coverage inture acetabulum contributes a better comprehension and practicability of THA forDDH patient clinically. Last, for acetabular reconstruction of Crowe I and II, due tothe superior and posterosuperior segmental defects, structural autograft is suggested toimprove the cup coverage. Besides, we could make full use of the acetabular bonestock of anterior and posterior column. For acetabular reconstruction of Crowe III andIV, considered of the poor bone stock of true acetabulum, we could moderately shiftthe acetabular center superiorly and (or) medially.