2025 ISAKOS Biennial Congress ePoster
Optimizing Screw Fixation in Open-Wedge High Tibial Osteotomy: The Role of Bioabsorbable Fillers in Enhancing Mechanical Stability
Jia-Lin Wu, MD, MS, Taipei TAIWAN
Sang Thanh Nguyen, MD, MS, Taipei TAIWAN
Po-Yao Wang, MD, Taipei TAIWAN
Jui Cheng Lin, MD, Taipei City, Taipei City TAIWAN
Taipei Medical University Hospital , Taipei , TAIWAN
FDA Status Not Applicable
Summary
The data suggest that bioabsorbable, customized gap fillers used in open wedge high tibial osteotomy could enhance stability by reducing displacement and stress differences between configurations.
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Abstract
Background
This study investigates the mechanical stability of Open-Wedge High Tibial Osteotomy (OW-HTO) plates using finite element analysis (FEA), with a particular emphasis on the role of bioabsorbable fillers in preserving structural integrity under various screw fixation configurations. The primary objective is to assess the impact of polycaprolactone (PCL)-based fillers on reducing overall structural displacement and stress, thereby providing valuable insights for the design of more minimally invasive implants.
Methods
Finite element models were developed to evaluate the stability of OW-HTO plates with and without PCL-based fillers across different screw configurations. Five alternative models incorporating fillers were subjected to simulated loading conditions equivalent to 1.5 times the body weight of an average person (approximately 720N and 480N). These configurations included fully populated screw models and those with selective omission of screws in the second row or specific diaphyseal locations.
Results
The analysis revealed that models incorporating PCL fillers exhibited significant reductions in maximum stress compared to baseline models without fillers, with stress reductions ranging from 55.77% to 58.96%. Moreover, all filler-inclusive models demonstrated lower overall structural displacement compared to the no-filler baseline, with reductions ranging from 22.65% to 28.53%. Wedge displacement analysis further indicated that the inclusion of fillers reduced movement by 12.64% to 42.72% compared to the baseline.
Conclusion
Polycaprolactone (PCL), a biodegradable polyester known for its bioresorbability and compatibility with 3D printing for bone defect structures, has been shown to significantly enhance the mechanical stability of OW-HTO by reducing both displacement and stress in this study. These findings suggest the potential for using fewer screws without compromising structural integrity, thereby facilitating the development of more minimally invasive surgical techniques. Such advancements could lead to shorter recovery times and improved clinical outcomes. Future research should aim to refine the design and material properties of these fillers to further enhance their biomechanical efficacy in clinical applications.
Keywords: Open-Wedge High Tibial Osteotomy, Finite Element Analysis, Mechanical Stability, Polycaprolactone, PCL Filler, Screw Configuration