Effect of Impact Velocity, Flooring Material, and Trochanteric Soft-Tissue Quality on Acetabular Fracture during a Sideways Fall: A Parametric Finite Element Approach

Abstract

A low-energy acetabular fracture, as a result of falling from standing height, is common among elderly patients and the number of cases is increasing rapidly in developed countries. Several biomechanical factors contribute to the incidence, severity, and type of acetabular fractures, such as body configuration at the impact moment or bone and soft-tissue quality. The current parametric study developed a comprehensive finite element model of the pelvic girdle and simple representation of the whole body and investigated the effects of impact velocity, conventional indoor/outdoor flooring material, and trochanteric soft-tissue stiffness on an acetabular fracture. Our results show that whereas the impact velocity has a substantial influence on the incidence and type of acetabular fracture, the effects of conventional flooring materials and trochanteric soft-tissue quality are not remarkable. It seems that other factors such as the quality of bone (healthy vs. osteoporotic), the thickness of trochanteric soft-tissue, and body configuration at the impact are more critical in the occurrence and type of the acetabular fracture. These results can be valuable in the prevention of acetabular fractures and the design of protective measures such as hip pads or novel flooring materials.

Effect of osteoporosis-related reduction in the mechanical properties of bone on the acetabular fracture during a sideways fall: A parametric finite element approach

“…This study is based on a 3D model of the human femur and pelvis derived from a database [ 6 ]. The model preparation and validation steps and the used materials were comprehensively presented earlier [ 16 ] and explained briefly here. This study was granted a register-based study permit (No.…”

“…The cortical, trabecular, and trochanteric soft tissues of the pelvic ring were thresholded and segmented using Mimics ® (version 21.0, Materialise Software, Belgium). The method assuring precise segmentation of cortical bone, especially in low-thickness regions such as acetabulum, was explained in our previous work [ 16 ]. Similar to the approach used by Majumder et al [ 12 ], the highest and lowest Hounsfield Units (HU) were assumed to be corresponding to the apparent density of cortical bone (1.8 g/cm 3 ) and marrow cavity (0.01 g/cm 3 ).…”

“…One such computational method is finite element modeling and analysis, which can address the questions related to relationships between applied forces and mechanical responses of tissue (stresses and strains). To the best of our knowledge, the studies conducted by Shim et al [ 14 ] and our group [ 15 , 16 ] are the only finite-element studies focusing on low-energy acetabular fractures at the tissue level. Our previous studies revealed that the effects of impact velocity and body configuration at the time of impact may substantially contribute to the severity and type of acetabular fractures.…”

“…Our previous studies revealed that the effects of impact velocity and body configuration at the time of impact may substantially contribute to the severity and type of acetabular fractures. Also, the trochanteric soft-tissue thickness was suggested to be more important in the prevention of low-energy acetabular fractures than trochanteric soft-tissue stiffness or flooring material type [ 15 , 16 ]. In these studies, the bone was assumed to be healthy, and the effect of reduction in the mechanical properties of bone caused by OP on the severity and type of low-energy acetabular fracture was not investigated.…”

“…This study aimed to assess the contribution of reduction in the mechanical properties of trabecular and cortical bone caused by OP on the acetabular bone failure and load-transfer mechanisms within the pelvic ring. Toward this goal, as a reliable approach in bone fracture prediction [ 11 , 15 , 16 , 28 , 29 ], a series of parametric finite element simulations of reduction in the mechanical properties of trabecular, cortical, and total bone (trabecular and cortical simultaneously) was done. The results of this study increase our knowledge about the effect of OP-related reduction in the mechanical properties of bone on the risk of acetabular fractures and load-transfer mechanisms within the pelvic ring.…”