Stress Evaluation of Lower Limbs with Hip Osteoarthritis and Hip Arthroplasty

Stress shielding and bone remodeling effects are critical issues in promoting long term stability of Total Hip Arthroplasty (THA). Stress shielding occurs when the femur experiences less stress after the presence of the prosthesis stem. In this study, biomechanical evaluations of lower limbs are established using the finite element method in corresponding to stress distributions. Lower limbs CT images of 64 years old female with hip osteoarthritis (OA) are used in developing three dimensional inhomogenous models. To represent THA limb, the left femur with hip OA problem was cut off and a prosthesis stem was implanted. The results show different stress distribution of lower limbs with OA and THA. Stress is defined to be concentrated at stiffer prosthesis stem while femur experienced less stress. The proximal region of femur is leading to stress shielding effects. Furthermore, gait instability is projected to occur based on the stress variation adaptation between operated and non-operated femur. 