A finite element analysis based sensitivity studies on pull out strength of pedicle screw in synthetic osteoporotic bone models

Pullout strength of pedicle screw is an important index used by surgeon and engineers for design and development of the implant. Increasing pullout strength is difficult since it is dependent on several factors such as density of bone, insertion technique etc. Current study uses a validated 2 D FE model of pullout strength experiment to study the effect of number of threads, inner and outer diameter and thread geometry on holding power of pedicle screw in a synthetic osteoporotic bone model. It was found that outer diameter has highest effect on pullout strength of pedicle screw. Coarser thread provides better holding power in an osteoporotic bone. This study can be used for developing screws with improved holding power in osteoporotic bone.