A finite element analysis approach to predicting intramedullary pressure during the insertion of prosthetic implants

Fat embolism syndrome is a serious post-operative complication of orthopaedic procedures such as fracture fixation and total joint replacement. Fat embolism syndrome can be a result of increased intramedullary pressure during the insertion of prosthetic implants in long bones. A macro was developed that automates the creation of finite element models representing a simplified bone/fluid/implant system and a hammering event. The finite element models were validated by computing the peak stresses at various locations in the bone and comparing them to pressures measured at similar locations in experimental tests. Finite element models were used to test the effect of using hollow implants on intramedullary pressure in the bone, in some cases yielding an average reduction of 19.1%. It has been shown that it is acceptable to use finite element models for such parametric studies and that hollow implants have the potential to decrease intramedullary pressure during insertion.