Finite element analysis of tibial prosthesis loosening after fixed-bearing unicompartmental knee arthroplasty for osteoporosis

Liu Wenlong; Dong Lei; Xiao Zhengzheng; Nie Yu

doi:10.12307/2026.541

Abstract：BACKGROUND:Osteoporosis is generally considered as one of the risk factors for tibial component loosening after unicompartmental knee arthroplasty.However,few finite element studies have investigated tibial component loosening after fixed-bearing unicompartmental knee arthroplasty in osteoporosis patients. OBJECTIVE:To investigate the slip and stress characteristics around the prosthesis by finite element method after the intervention of cancellous bone slotting and reduction posterior slope under different bone mineral density. METHODS:The three-dimensional model of the knee joint of a 61-year-old female patient with knee osteoarthritis was reconstructed by computed tomography.Subsequently,fixed-bearing unicompartmental knee arthroplasty surgery was performed on the three-dimensional model in the computer,and the intervention of tibial cancellous bone grooving and reducing the angle of retroversion was implemented.Then,the material parameters were assigned to the osteoporosis and non-osteoporosis,respectively.The finite element analysis method was used to verify whether tibial slotting and changing the tibial posterior tilt angle would affect the aseptic loosening rate of the prosthesis. RESULTS AND CONCLUSION:(1)In the finite element analysis of fixed-bearing unicompartmental knee arthroplasty,the bone bearing capacity of the osteoporosis knee was weaker than that of the non-osteoporosis knee.(2)The tibial component with different bone mineral density was more prone to the anteroposterior slip than the medial and lateral slip.(3)The degree of cancellous bone slip was reduced after the transverse groove design,which could prevent the loosening of the prosthesis.(4)For the osteoporosis knee,the tibia with reduced posterior slope(6° to 4°)had a stronger ability to bear load,and the possibility of prosthesis loosening was reduced.(5)The scheme of reducing posterior slope and opening transverse groove at the same time had advantages in preventing postoperative prosthesis loosening,and this advantage was more significant in osteoporosis knees.