Nonlinear finite element analysis of hip prosthesis micromotion in one gait cycle

The purpose of this study is to explore the micromotion characteristics of prosthesis in gait cycle under physiological load. An anatomical CAD model of total femur was generated from CT image. The prosthesis was virtually implanted into the femur model with surgically position to form a nonlinear FEA contact model. Gait cycle was divided into 8 gait event as load step. The FEA analysis shows the micromotions of prosthesis are two kinds of rotation around the frontal axis and the sagittal axis respectively, the magnitude of the bone-implant relative micromotion range in 25 μm in one gait cycle. The micromotion is the main cause which will lead to long-term aseptic loosening of prosthesis.