Dynamic Stress Analysis of Bone-Prosthesis Complex duringStance Phase of Gait: a Preliminary Approach to THRLoosening Characterization

Loosening of artificial hip joint is the most prevalent failure of patientswho has undergone Total Hip Arthroplasty (THA). There are many role-playingfactors result in loosening, e.g., geometry of prosthesis, implantation procedure andtechnique, existence of voids within bone cement, patient lifestyle, etc. In this studywe have focused on analyzing dynamic stresses and strains at interface of bone andimplant in stance phase of human normal gait in order to propose and prove one ofprobable loosening causes. We have also proposed an appropriate biomechanicalparameter called Bone-Prosthesis Strain Difference (BPSD) as an effectiveparameter playing a very important role in loosening procedure. For this reason, a2D cross-sectional model was employed in frontal plane, and then the simulation wasdone utilizing ADINA FEA package. The results established the differencestresses/strains values in medial and lateral areas of interface, as well as, regions inhigh risk of loosening which are important either in clinical THA surgery or inmechanical design of artificial hip joints.

Keywords:

THA , loosening , bone-prosthesis strain difference , FEA