In case effects of proximal fibular osteotomy and total knee arthroplasty on load distribution in the human knee: A comparative finite element study.

Abstract

Objectives: This study aims to quantitatively compare the biomechanical effects of proximal fibular osteotomy (PFO), total knee arthroplasty (TKA), and combined TKA+PFO on load distribution in the human knee under physiological axial loading.

Materials and methods: Four finite element models were constructed from high resolution computer-aided design (CAD) geometries: intact knee, PFO, TKA (cobalt chromium femoral/tibial components with polyethylene insert), and TKA+PFO. Linear elastic, isotropic material properties were assigned to bone, menisci, and implant components. Each model was meshed with 10 node tetrahedral elements (1-mm element size) in ANSYS workbench 2022 R2. A static axial load of 750 N was applied to the femur; distal tibia and fibula surfaces were fully constrained. Total deformation and von Mises stress were extracted for anterior (A), posterior (P), medial (M), lateral (L), and global maximum (Max) regions, and percentage deviations (Δ) were computed relative to the intact model.

Results: The PFO increased regional deformations by 68 to 74% and redistributed stress posteriorly (+104% in P), with modest stress reductions anteriorly (-11%) and medially (-17%). TKA alone increased deformations by 39 to 46%, while reducing stress by >95% anteriorly, medially, and posteriorly, and ~65% laterally. Both TKA+PFO produced the greatest compliance increase (Δ>114%) and deepest stress off-loading (global Δ ≈-84%). The combined approach synergistically minimized peak stresses (~5.6 MPa) at the expense of maximal deformation (~6.0 mm).

Conclusion: Our study results suggest that PFO and TKA exert distinct biomechanical modifications and their combination offers more satisfactory stress reduction, but markedly increases compliance. We believe that these findings can be used to tailor surgical planning and implant design and to optimize joint mechanics.