In the present study, medical CT images were utilized to develop 3D-computational models of hip joints and femoral bones. The finite element analysis was then performed to characterize the biomechanical problems associated with the bone models. The FEA results clearly exhibited dramatic changes of stress and SED profiles due to osteoarthritis and hip arthroplasty. Furthermore, a damage modelling was also introduced into the FEA to characterize the fracture problems of femoral bone with prostheses under a downstairs step and sideways fall conditions. Micro-damage formations are well predicted in the vicinity of the prostheses for bone cases. It is thus confirmed that CT-FEA can be very useful to understand the biomechanical problems in the field of orthopaedics.