Background/Aim. One of the possible complications after implantation of a
cement hip-joint endoprosthesis is fracture in the endoprosthesis body.
Fractures arise from overload or material fatigue of which an implant is
made. The purpose of this research was to define the intensity of maximum
stress and the positions of a critical cross-section in the endoprosthesis
body. Methods. Unilaterally changing forces which act on the hip joint during
walking as well as the loads result in flexible deformations of the
endoprosthesis body. Biomechanical analysis of the forces acting on the hip
joint determine their direction and intensity, whereas on the basis of
Gruen?s classification of the endoprosthesis body loosening the level of
fixation is established. The bodies of cement hip joint endoprosthesis are
made of cobalt-chromiummolybdenum (CoCrMo) alloy, suitable for vacuum
casting, are submitted to the analysis. Analysis of the critical stress in
the endoprosthesis body was performed on the endoprosthesis body by means of
the finite element method. The experimental verification of the obtained
results was carried out on the physical prototype under laboratory
conditions. Results. Computer analysis, by means of the finite element
method, determined the stress state by calculation of the maximum Von Mises
stress and critical cross-sections for different angles of the resultant
force action. The results obtained by the computer and experimental method
correlate and are comparable to the results of similar analyses conducted on
various endoprosthesis types. Conclusion. The analyses described in the paper
make the basis for improving the process designing of hip joint
endoprostheses and their customization to each individual patient (custom
made).
Biomechanical Analysis of Hip Joint Arthroplasties using CT-Image Based Finite Element Method