Abstract
Aim
To delineate which of four common and easily constructed Ilizarov frame configurations is best at resisting shear displacement.
Methods
Four Ilizarov frames were constructed on Sawbones™ Tibiae taking into account soft tissue and neuro-vascular limitations in frame design. The designs consisted of a standard all wire frame, an opposing olive wire standard frame, a perpendicular trans-fracture opposing olive wire frame and a perpendicular half pin frame. These were tested over three cycles in compression on a load-testing machine with movement in the plane of the fracture measured using a clip gauge. Each frame was tested to the maximum displacement of the clip gauge or a total single cycle compressive load of 700N, whichever limit occurred first.
Results
The perpendicular trans-fracture olive wire frame showed the least displacement in shear. The half pin frame, followed by the opposing olive standard frame and finally the all wire frame were least stable to shear displacement.
Conclusion
For this fracture pattern, this study recommends the use of the perpendicular trans-fracture olive wire frame. Further investigation of immediate post-operative limb loading in patients will allow practical application of this data.
Further frame motion analysis and bending analysis will allow validation of these results and allow for future frame design.
The next steps in this project involve validation against FE Analysis in order to create a design software to allow mechanical templating of frame designs pre-operatively.
