ABSTRACT
Cementless femoral components need exact contact to the supporting cortical bone and optimal fit (surface area of the implant indirect contact with the endosteal surface) and fill (the percentage of the cross-sectional area of the femoral canal occupied by the prosthesis) of the proximal femur to reduce micromotion and obtain primary stability for bony in-growth and long-term
1 INTRODUCTION
Total Hip Replacement (THR) is applied operation aimed at restoring damaged hip joints with the use of artificial implants. These implants replace the patient’s hip joint with a mechanical device that mimics the bone-hip connection (Gelalis et al. 2001). This is especially true when the responsible disease (e.g. osteoarthritis, rheumatoid arthritis, hip dysplasia …) is at an advanced stage and causes anatomical malformations (Raut et al. 1995). The number of THR operations is growing each year and has become the second most performed surgical procedure with an estimated number of 1,000,000 operations each year worldwide (Diels et al. 2000). As shown in Figure 1, implants can either be fixed to the cavity of femoral by an interfacing layer of flexible polymeric cement like PMMA or directly forced (press-fitted) into the cavity of femoral (i.e. cemented and cementless implants, respectively). (Kowalczyk 2001).
