060 COMBINING BIGGER FEMORAL HEADS WITH MODULAR NECKS IN TOTAL HIP ARTHROPLASTY. A FINITE ELEMENT ANALYSIS

Abstract

Total hip arthroplasty is nowadays a common treatment for a large number of pathological cases regarding the hip joint and is considered as the most successful orthopedic operation. With the mean age of patients constantly decreasing and the more intense way of life, the need for versatile implant designs has arisen. Currently modular hip implant systems are used extensively in order to compensate for difficult occasions, where offset and version correction are required. In addition to this femoral heads of bigger diameter have been introduced to deal with issues such as dislocation and impingement, although their influence on the mechanical behavior on the bone – implant assembly is not widely documented. Towards this direction a finite element model was generated. Computed tomographies of a cadaveric femur were used as raw data and processed, a Profemur-E system with variable heads was digitized, thus leading to a complete assembly consisting of the femur, the stem, the necks and the femoral heads in the commercial CAD software Solidworks. For typical loading scenarios – the stance phase of the gait cycle – the finite element analysis was performed in ANSYS Workbench. The results showed that the implementation of BFH and the neck version produced an increase in strains and stresses with respect to a normal head of 28mm and a straight neck in areas of clinical interest such as the calcar, the greater trochanter area and the stem tip region, considered responsible for thigh pain.