Effect of Dega Osteotomy on the Biomechanics of the Hip Analyzed with the Method of Finite Element Analysis

Introduction: Hip osteotomies are performed in the treatment of developmental hip dysplasia for anatomical reconstruction of the deformity. Dega osteotomy is an acetabuloplasty indicated in childhood treatment. In this study we performed a finite element analysis of the hip in order to clarify the effect of the Dega osteotomy on biomechanics of the dysplasic hip.
Material and methods: We used the CT data from two children: one with normal hip for reference, and one with dysplasia of the left hip. After the reconstruction of the geometrical models for normal, dysplasic, and post-Dega osteotomy hips, we made a finite element analysis for each model, using hexahedral elements.
Results: In our postoperative model the intrarticular pressure decreased from 5.7 MPa in the dysplasic model to 3.5 MPa. The acetabular contact area in the post-osteotomy model increased two times compared to the dysplasic model.
Conclusions: The positive effects of the Dega osteotomy on the biomechanics of the dysplasic hip is proved in the size and shape of the postoperative contact areas, which are almost the size and shape of the normal hip.

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