General deformable 3D hip prosthesis model creation for patient-specific implant design according to several anatomical requirements

Abstract

Even though the THA surgical procedure is considered to be among the most successful, safe and cost-effective surgical procedures, implant failures related to prosthesis design and placement still occur in a considerable number. Therefore, as it is one of the most common interventions, improvements in the design of the prostheses would benefit a significant number of patients, potentially reducing failure and accurately adjusting the implant to the patient. It also can be seen as a new approach, where it is the prosthesis that fits the patient and not the other way around. This work is a contribution with the Radiology Department of the Hospital del Mar where the main purpose of this research was to systematically generate 3D model that can be deformed with the goal of creating patient-specific hip implant designs. Instead of creating new CAD models, a virtual library of 3D models from part of the standard existing designs that have been shown to work more or less well over a long history of orthopedic hip surgery was generated. Then, comparing all shapes after point registration, a statistical shape model which has the capacity to deform was created. So, modifying relevant parameters of the model, it can adapt to certain anatomical landmarks of each patient. The results showed accurate shape registration which leads to a relevant significant deformation but needs refinement to fit all the parameters to replace the hip joint. In conclusion, the mesh morphing method proposed is a first step for the creation of patient-specific CAD models that can adapt to the dimensions of the anatomical requirements.