Design of a prototype bioresorbable tibial implant in a sheep model

The purpose of this study was the design of a prototype calcium polyphosphate tibial implant for implantation into a sheep. In the design, several design parameters were considered: CPP implant structural strength, the maximum allowed micromotion of the structure at the interface with bone and the possibility of the surgeon implementing the necessary geometric changes on the bone elements during implant surgical insertion. A fininte element analysis facilitated the design and allowed for the effects of the various geometric parameters investigated. This analysis was based on a real solid model of the sheep tibial bone based on the CT scans of a five year old sheep, and several were the geometeric parameters investigated. The approach of the finite element analysis was very conservative, in the meaning that the load applied was purposely increased in order to account for any possibly unknown factors that may exist and not implemented in the analysis.