The Influence of the Number of Holes in the Open Wedge High Tibial Osteotomy on Knee Biomechanics using Finite Element Analysis.

Abstract Background: The most significant differences of high tibial osteotomy (HTO) were found in terms of plate length, and this was related to number of holes near the wedge distal region of the plate. The purpose of this study is to evaluate the biomechanical effects of three different medial opening wedge plates. Hypothesis: The design of the HTO plate influenced the outcome of the biomechanics. Methods: The HTO model was simulated using finite element (FE) model. This FE investigation included three types of loading conditions corresponding to the loads used in the experimental study for model validation and model predictions for clinically relevant loading scenarios. The average stress and constact stress were evaluated. Results: The highest average stress was observed in the TomoFix. Conversely, the stress on the bone declined in the order of Puddu, Maxi and TomoFix plates. The micromotion in the wedge displayed a similar trend to the stress on bone. The highest and lowest contact stresses on the medial meniscus were observed in the TomoFix and Puddu plates, respectively. However, an opposite trend was observed in the lateral meniscus. The contact stress on medial and lateral menisci decreased and increased, respectively, in all three different plates when compared to those in the intact model. Discussion: The TomoFix plate exhibited the highest stability relative to the micromotions of the wedge. However, in terms of the stress on the bone and plates, a stress-shielding effect could exist in the TomoFix plate. Additionally, the contact stress on the articular surface suggested that a complicated relationship could exist with respect to the plate design. Level of evidence: IV