Development of a composite bone plate for fixation of a fractured tibia

A finite element model has been used to show how a composite bone fixation device compares in performance with an equivalent stainless steel plate. It has previously been shown[2] that the reduced modulus of the composite plate provides a better environment for healing in the early weeks after fracture. The results of the new work demonstrate that the composite plate also gives a more even transfer of load via screws from the plate into the bone for a realistic friction coefficient of 0.4. A cohesive zone model of failure of the healing callus has been used to illustrate how the stiffer steel plate provides a better protection against overloads in the early phases of healing, at the expense of providing a less good environment for healing. Finally it is shown that the composite lay-up can be adjusted to provide an optimum environment for healing, depending on the applied axial and torque loading