Significance of Lateral Pillar in Osteonecrosis of Femoral Head

Abstract

Background:The lateral pillar of the femoral head is an important site for disease development such as osteonecrosis of the femoral head. The femoral head consists of medial, central, and lateral pillars. This study aimed to determine the biomechanical effects of early osteonecrosis in pillars of the femoral head via a finite element (FE) analysis.Methods:A three-dimensional FE model of the intact hip joint was constructed from the image data of a healthy control. Further, a set of six early osteonecrosis models was developed based on the three-pillar classification. The von Mises stress and surface displacements were calculated for all models.Results:The peak values of von Mises stress in the cortical and cancellous bones of normal model were 6.41 MPa and 0.49 MPa, respectively. In models with necrotic lesions in the cortical and cancellous bones, the von Mises stress and displacement of lateral pillar showed significant variability: the stress of cortical bone decreased from 6.41 MPa to 1.51 MPa (76.0% reduction), while cancellous bone showed an increase from 0.49 MPa to 1.28 MPa (159.0% increase); surface displacements of cortical and cancellous bones increased from 52.4 μm and 52.1 μm to 67.9 μm (29.5%) and 61.9 μm (18.8%), respectively. In addition, osteonecrosis affected not only pillars but also adjacent structures in terms of the von Mises stress and surface displacement levels.Conclusions:This study suggested that the early-stage necrosis in the femoral head could increase the risk of collapse, especially in lateral pillar. On the other hand, the cortical part of lateral pillar was found to be the main biomechanical support of femoral head.

Biomechanical Analysis of Fibular Graft Techniques for Nontraumatic Osteonecrosis of Femoral Head: A Finite Element Analysis

“…Moreover, one patient in Type C1 and one patient in Type C2 were employed to validate the biomechanical properties of LBT. The shape and location of stress transfer path in this study is relevant to previous studies, which showed that stress transfer path was consistent with the distribution of bone density 19,29,30 . In addition, the average stress of weight-bearing area after bula implantation, ranging from 2.32 to 2.59 Mpa, were in accordance with a recent study 28 .…”

“…The necrosis of femoral head varies from cases to cases, thus appropriate classi cation is prerequisite for the modelling. The JIC classi cation is a direct evaluation method to re ect the relative position between necrotic lesions and the weight-bearing area [31][32][33] , and has been proved to be an appropriated classi cation to predict stress distribution of the hip joint in vivo 19,30,34,35 . In the JIC classi cation, Type C1 and C2 are recommended to undergo joint-preserving therapies, so both types were employed in this study.…”

The effect of the necrotic area on the biomechanics of the femoral head - a finite element study

“…The model used in the study was built using ABAQUS 6.14 FE analysis software (Dassault Systems Simulia Corp., Providence, Ri, USA). Details of the model's construction method, material properties, validation, and convergency testing have been reported in the previous article [22]. The schematic diagram and magnetic resonance imaging (MRI) of CJFH classification for ONFH based on three pillars were shown in Fig.…”

“…The weight-bearing area of the femoral head is mainly located on the anterolateral side of the femoral head, and the contact area of the femoral head to acetabular was approximately to be circular [22,23]. Therefore, the lateral contact area of the femoral head was emphatically studied, and the data from the same 17 points on the surface of this area in each model were collected for statistical analysis, as shown in Fig.…”

Finite Element Modeling of Proximal Femur with Quantifiable Weight-Bearing Area in Standing Position

“…In our previous research, we established the standing hip model to perform mechanical research and recognized that in the standing position, the contact area as well as the weight-bearing area of femoral head as the direct active surface of joint force, its positional distribution and size can directly affect the stress distribution of the femoral head [3]. Studies [4,5]believed that the weight-bearing area of the femoral head was mainly located on the anterolateral side of the femoral head, and the contact area of the femoral head to acetabular was approximately to be circular.However, we know that the shape of the contact between the acetabulum and the femoral head is elliptical.Furthermore, the circular contact may cause errors in the finite element simulation and is more likely to cause stress concentration in the femoral head,which can affect the authenticity and accuracy of FEA.So, before a biomechanical FEA of the separate femoral head be carried out, it is necessary to define the weight-bearing area scientifically. Genda et al [6] reported a method for calculating hip joint contact area in single-legged standing posture by X-ray film and verified its accuracy, but this method has not been applied to real case based FE model.…”