Finite element analysis of intra-extramedullary combined reconstruction technique for treating ultra-large bone defects
LIU Hairui
ZHANG Xiaoyu
GAO Song
FAN Jian
XIAO Xin
DING Shi
MA Ziyang
LU Yajie
LI Jing
Abstract：Objective To evaluate the mechanical performance of the intra-extramedullary combined reconstruction technique(IECRT)prosthesis and the conventional tumor knee prostheses in the reconstruction of ultra-large bone defects from a biomechanical perspective,providing a theoretical basis for the clinical application of IECRT prostheses.Methods Based on CT data from the femur of a 32-year-old healthy male,a three-dimensional femoral model was established in Mimics 21.0,and a 20 cm osteotomy was performed to create an ultra-large bone defect model.The IECRT prosthesis and conventional tumor knee prosthesis were designed in SolidWorks 2021.The prosthesis and bone models were imported into Ansys 2024 to establish a finite element analysis model.Four loading conditions(standing,walking,ascending stairs,and descending stairs)were simulated in the finite element analysis to evaluate the performance of the reconstruction.Results Under the four loading conditions,the peak displacement of the intramedullary stem of the IECRT prosthesis was lower than that of the tumor knee prosthesis[standing:0.11 mm(tumor knee prosthesis group:0.25 mm);walking:1.80 mm(tumor knee prosthesis group:3.35 mm);ascending stairs:2.85 mm(tumor knee prosthesis group:5.00 mm);and descending stairs:2.07 mm(tumor knee prosthesis group:3.79 mm)].In terms of von Mises stress,except for the standing condition,the peak stress of the intramedullary stem of the IECRT prosthesis was lower than that of the tumor knee prosthesis under the other three conditions[standing:12.40 MPa(tumor knee prosthesis group:9.49 MPa);walking:168.95 MPa(tumor knee prosthesis group:208.50 MPa);ascending stairs:272.56 MPa(tumor knee prosthesis group:356.82 MPa);and descending stairs:197.05 MPa(tumor knee prosthesis group:244.14 MPa)].Conclusion The IECRT prosthesis system can stably reconstruct femoral ultra-large bone defects.Compared with conventional tumor knee prostheses,the intramedullary stem of the IECRT prosthesis exhibits lower peak displacement and von Mises stress,more uniform stress distribution,and no stress shielding,thereby reducing the risk of prosthesis failure.
Keywords：ultra-large bone defectsbone defect reconstructionfinite element analysisintra-extramedullary combined fixationosteosarcomabiomechanicsprosthetic implantfemur
Publication Date：2026-04-30
Online Publishing Date：2026-08-26(First online date of this platform, not the publication date of the document)
Pages：7( 539-545 )