Comparison of pre and postsurgical stress over a hip joint with dysplastic sequels

© 2015, Editorial Ciencias Medicas. All rights reserved. Introduction: the treatment of residual hip dysplasia in young persons and adults requires surgery. Bearing in mind the future biomechanical behavior of the joint could be a useful tool in the planning and evaluation of the most appropriate surgical procedure. Objective: compare the distribution of pre- and postsurgical stresses over a hip joint with dysplastic sequels using the finite element method for its resolution. Methods: use was made of a finite element model of a patient's hip joint with dysplastic sequels reconstructed from computerized axial tomography images, and a model of the joint relocation that simulated the surgical procedure performed. The maximum stress generated and the weight bearing area were estimated during the stance phase of the gait cycle. Results: the load on the treated joint was excessive due to the reduced joint coverage. Simulations on the postsurgical model revealed a 20.20% reduction in the maximum effort exerted on the femoral head at the point of greatest load during the gait (20% of the support stage), a 49% reduction in the contact pressure over the joint cartilage, and a 64% increase in the weight bearing area at the same point. Conclusions: the study reveals very considerable postsurgical biomechanical improvement in the amount of load borne by the joint. On the other hand, it allows a better view of the patient's reality and contributes to taking the best treatment decisions.