Effects of proximal fibular osteotomy on tibiofibular and medial knee loads in severe varus: A finite element study

Abstract

Objectives: This study aims to evaluate the biomechanical effects of proximal fibular osteotomy (PFO) on tibiofemoral and proximal tibiofibular load transfer under simulated neutral and varus alignment conditions using a lower-extremity finite element analysis (FEA) model.

Materials and Methods: A patient-specific three-dimensional FEA model of the lower extremity was developed from computed tomography and magnetic resonance imaging data of a healthy volunteer. Neutral, 3° varus, and 5° varus alignments were simulated before and after PFO under a simplified physiological axial load of 900 N. Tibiofemoral compartment forces, proximal tibiofibular joint (PTFJ) force, distal tibiotalar reaction force, and peak von Mises stresses within the cartilage-meniscus complex were evaluated.

Results: Proximal fibular osteotomy markedly reduced PTFJ force across all alignment conditions. Under neutral alignment, PTFJ force decreased from 122.94 N to 21.84 N, while distal tibiotalar reaction force increased from 787.55 N to 897.89 N, indicating redistribution of load through distal pathways. Tibiofemoral compartment forces changed minimally. Under 5° varus alignment, medial tibiofemoral force decreased only from 608.45 N to 603.78 N following PFO. Peak medial meniscal and cartilage stresses increased with varus alignment and remained largely unchanged after osteotomy.

Conclusion: In this single-subject static FEA model, PFO substantially reduced proximal tibiofibular loading, but produced only limited changes in tibiofemoral load distribution under simulated varus alignment. Within the present model, load redistribution occurred predominantly through distal load-transfer pathways rather than substantial unloading of the medial tibiofemoral compartment. These findings suggest that the biomechanical effect of PFO may primarily involve alteration of fibular load transmission rather than meaningful reduction of medial knee loading.

Citation: Pekince O, Yıldırım A. Effects of proximal fibular osteotomy on tibiofibular and medial knee loads in severe varus: A finite element study. Jt Dis Relat Surg 2026;37(3):800-810. doi: 10.52312/jdrs.2026.2965.

O.P.: Contributed to the study conception and design, supervised the study, and drafted the manuscript; A.Y.: Contributed to study design, manuscript drafting, and critical revision. Both authors reviewed and approved the final manuscript.

The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

The authors received no financial support for the research and/or authorship of this article.

The authors would like to thank Musa Güngörürler for his valuable contributions to the development of the finite element model and technical support throughout the study.

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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