[3D finite element analysis of bone stress around distally osseointegrated implant for artificial limb attachment]

Using the CT data, we have constructed the finite element models of human femur distally amputated at high-position, middle-position and low-position, along with distally osseointegrated implant under the maximal load during a normal walking cycle. Results of finite element analysis revealed: the maximal stress of implant is produced near the exit of the amputated limb, where the fatigue breakpoint caused by cyclic stress would take place. With the ascending of truncated position, the peri-implant interfacial stress of bone increases. There is severe stress-shielding at the bone-implant interface, and there is concentration of stress at the end of implant and at the 3/4 point of femur, which would lead to bone loss and bone resorption and would shorten the longevity of implant. The results also showed that the curvature of natural bone has notable effect on the stress distribution, which should not be neglected. These data may provide reliable reference for the design and research of osseointegarted artificial limb.