The effect of rotational degree and routine activity on the risk of collapse in transtrochanteric rotational osteotomy for osteonecrosis of the femoral head—a finite element analysis

Abstract

To explore the mechanical mechanism and provide preoperative planning basis for transtrochanteric rotational osteotomy (TRO) procedure, a joint-preserving procedure for osteonecrosis of the femoral head. Eleven TRO finite element femurs with the most common types of necrosis were analyzed under multi-loading conditions. Thereafter, we made a comprehensive evaluation by considering the anatomy characters, daily activities, and risk indicators contain necrosis expansion trend, necrotic blood supply pressure, and the risk of fracture. The risk of fracture (ROF) is the lowest when standing on feet and increases gradually during normal walking and walking upstairs and downstairs. Compared with posterior rotation, rotating forward keeps more elements at low risk. Additionally, the correlation analysis shows it has a strong negative correlation (R 2 = 0.834) with the average modulus of the roof. TRO finally decreased the stress and energy effectively. However, the stress and strain energy arise when rotated posteriorly less than 120°. The comprehensive evaluation observed that rotating forward 90°could reduce the total risks to 64%. TRO is an effective technique to prevent collapse. For the anterior and superior large necrosis, we recommend to rotate forward 60°to 90°(more efficient) or backward 180°. The methodology followed in this study could provide accurate and personalize preoperative planning. Keywords Osteonecrosis of the femoral head . Transtrochanteric rotational osteotomy . Routine activity . Risk of collapse . Finite element analysis Pusheng Xie, Yuping Deng and Jinchuan Tan contributed equally to this work. * Hanbin Ouyang

Shape Optimization of Costal Cartilage Framework Fabrication Based on Finite Element Analysis for Reducing Incidence of Auricular Reconstruction Complications

“…Several clinical investigations of auricular reconstruction also demonstrated the skin necrosis typically observed at the helix after first-stage modification, which is consistent with our dynamic FEA results ( Kim et al, 2017 ; Cugno and Bulstrode, 2019 ). The digital image correlation (DIC) test ( Maiti et al, 2016 ; Xie et al, 2020 ) was conducted simultaneously to verify the validity of FEA models; due to the complex three-dimensional structure of ear cartilage, the areas of the concha and lobule were absent during the acquisition process with the DIC system. Therefore, the relatively flat locations of the whole ear cartilage in the DIC measurements were selected to compare with the same areas of the FEA contour plot.…”

Reconstruction of massive bone defects after femoral tumor resection using two new-designed 3D-printed intercalary prostheses: a clinical analytic study with the cooperative utilization of multiple technologies

“…A 3D model of the femur was generated with MIMIC software. The body mesh was divided, and the tetrahedron elements were utilized to produce mesh models [ 30 ]. To calculate each element’s modulus of elasticity, the HU value was extracted from CT images and was calculated at the central point of each element.…”

“…Interior bone density was converted to elastic modulus for each element based on an empirical relationship specific to bone. Equations 1 and 2 were applied to determine the apparent density (ρ, g/cm3) and Young’s modulus (E, MPa) of each element, respectively [ 30 ]. The value of Poisson’s ratio was 0.3.…”

Optimal Design and Biomechanical Analysis of a Biomimetic Lightweight Design Plate for Distal Tibial Fractures: A Finite Element Analysis

“…To calculate each element’s modulus of elasticity, the Hounsfield unit was extracted from CT images and calculated at the centroid of each element. Formulas 10 and 11 were used in previous studies ( Chen et al, 2010 ; Nourisa and Rouhi, 2016 ; Xie et al, 2020 ) to find the apparent density (ρ) and Young’s modulus ( E ) of each element. …”