TS9: PERIARTICULAR IMPLANTS – OPTIMISATION OF PLATE DESIGN WITH COMPUTER MODELLING

Abstract

Introduction: With the development and popularisation of minimally invasive surgical methods and implants, it is increasingly important that available implants are pre-contoured to the specific anatomical location for which they are designed. From a clinical point of view, an anatomically well fitting plate can greatly facilitate the process of closed reduction in terms of axial and rotational alignment of the main fragments. Furthermore, such a plate may additionally protrude less and therefore minimise soft tissue irritations. Clinical practice and recent research shows that some of the current pre-contoured fracture fixation plates do not fit well for certain patient groups ^1,2. This study reports on a method for optimising the shape of a plate for a given dataset.

Methods: Forty-five 3D models of the outer bone contour of Japanese tibiae were generated from CT image data. The fit between bone models and the undersurface (bone facing) of a distal medial tibia plate was quantified using the reverse engineering software RapidForm2006 (Inus Technology Inc., Korea). An anatomical fit of the plate was defined with four criteria². The current plate shape was optimised in the virtual environment using computer graphical tools of RapidForm2006.

Results: The current plate shape achieved an anatomical fit on 13% of tibias from the dataset, whereas the modified plate achieved an anatomical fit for 67% of the bone models.

Conclusion: Computer graphical methods enable optimisation of the shape of an existing plate resulting in a significantly improved fitting for the bones of the available dataset.