Finite element analysis of tibia with osteogenesis imperfecta: the influence of considering cancellous bone in model reconstruction

The paper aims to develop the finite element (FE) models of tibia with Osteogenesis Imperfecta (OI) based on a patient-specific computed tomography (CT)-images. Two types of FE model have been developed. The first model was set the tibia bone as a single solid model whereas the second model consists of cortical bone and cancellous bone. The developed FE models were used for FE analysis using Voxelcon under various loadings, and then the results of the different models were compared. It was found that the single model yields relatively in agreement to piecewise model, with percentage different of below than 2% for all loading conditions. It seems that the reconstructed FE model considering the cancellous bone did not give significant effect compared to the solid model that neglecting the microstructure of cancellous bone. Hence, we can conclude that the single solid FE model with OI has predicted well, at least for the present boundary conditions, although the cancellous bone was neglected in the model reconstruction

Fracture prediction on patient-specific tibia model with osteogenesis Imperfecta under various loading direction

This study aims to predict the fracture of bone with osteogenesis imperfecta (OI) by considering the homogenization properties of real patient. A Type-III of osteotomy in OI femur was used as bone specimen. Nine representative volume element (RVE) models were developed based on μCT-images of bone specimen. Homogenized properties particularly the Young's moduli of the RVEs was obtained based on homogenization theory in Voxelcon software. The obtained homogenized properties were then assigned to the OI patient-specific model that was developed from CT-images of real patient. The fracture of OI bone was predicted based on linear static analysis and finite element method under loadings of activity daily living (ADL). The results found that the fracture might be happen to the patient under jumping load case, whereas the subject is expected to be safe under standing still and walking load case

Modelling of patient-specific femur with osteogenesis imperfecta to determine the fracture risk under various loads

Osteogenesis imperfecta (OI) is a fragile bone disease characterized by easy fractures. The femur consists of cortical and cancellous bone, each with different mechanical properties. Bone fractures often occur throughout patients’ lifetime. However, doctors still have no quantitative method to predict fractures. Therefore, this project’s purpose is to investigate the OI femoral fracture risk to help prevent fractures. The project consists of three sections; cortical and cancellous segmentation, reconstruction of 3D OI femoral model and finite element analysis (FEA) of the OI femur to obtain fracture risk. The fracture risk in daily activities and the fracture load were examined. All the stress values were judged by the fracture criteria, assumed as 115 MPa. The exercises that exerted force more than 6 times of body weight can cause fractures. In addition, the optimal compressive force and tensile force were 919.7 N and 912.1 N, respectively, while medial and lateral impact were 230.8 N. Cancellous bone was not affected even a fracture happen. Based on these findings, we can conclude that when the OI femur is subjected to lateral or medial forces, the femur breaks easily. The bone can be reconstructed into a solid body without having to separate bone into cortical and cancellous

Determination of fracture risk on patient-specific model of femur with osteogenesis imperfecta

Osteogenesis Imperfecta (OI) is a group of genetic disorder that affects the bones. It causes bone to break easily. For severe case, it can lead the patient to death. However, doctors still have no quantitative method to predict fractures. Therefore, this study aims to investigate the fracture risk for OI femoral bone under load of activities in daily living and various loading direction. A finite element model reconstructed from radiography CT images was developed. The variations of daily activities were subjected to the femoral model. In standing and walking configuration, the model of OI has the ability to perform without having any fracture. However, during jumping, both configurations cause the OI femoral fractured. We can conclude that when the OI patients more active in their daily life, the higher chances for fracture to occur. The risk of fracture increases with increasing the intensity of the activity. Thus, early prediction of fracture risk could help prevent or treating fracture for OI patients

Influence of Synchronized Dead Point Elimination Crank on Cyclist Muscle Fatigue

The aim of this study was to investigate the influence of newly proposed bicycle’s crank to crank angle setting on the Vastus Lateralis (VL) and Bicep Femoris (BF) muscle activity during cycling. Procedures of Conconi Test were used throughout the experiment for the data collection purpose. The muscles activities were recorded using surface electromyography and software LabChart7. The raw data were further processed in time (Root-Mean-Square, RMS) and frequency (Mean Power Frequency, MPF) domain. It was found that 0° crank to crank setting (similar to conventional crank to crank angle setting) caused the prime mover VL (Normalized RMS = 0.119) to fatigue more than BF (Normalized RMS = 0.102). This setting is expected to decrease the cycling performance. In addition, −5° is the best crank to crank angle setting that causes least fatigue to both VL and BF. In short, to increase the cycling performance by avoiding the fatigue to the main muscles, −5° is the suggested as setting angle for the proposed crank design

Nanoindentation measurement on interstitial and osteon of bone with osteogenesis imperfecta-type III

"Osteogenesis imperfecta (OI) is one of the genetic disorder which was characterized by bone fragility. Previous studies reported that there are several mechanical properties has been used to investigate the strength of OI bone. However, little data is yet available to describe bone material properties in individuals with this disorder for type III alone. Therefore, the aim of this study is to investigate the mechanical properties in individual with OI bone type III at interstitial and osteon. Bone tissue reduced modulus and hardness were measured by nanoindentation in three specimens with total 40 indents. These properties were compared between osteogenesis imperfecta types III for interstitial and osteonal microstructural regions. Individual with osteogenesis imperfecta type III had higher hardness and reduced modulus at interstitial rather than osteonal bone regions. Overall, the mean and standard deviation of hardness is 0.6 ± 0.11 GPa, while 0.44± 0.06 GPa for osteon. The current study presents the dataset describing the bone material properties in individual with Osteogenesis Imperfecta Type III. Results indicate that intrinsic bone tissues properties were affected by phenotype. Knowledge on the mechanical properties of severity osteogenesis imperfecta may help to assist the model and prevent the fracture risk for those having this disorder.

Influence of Initial Crank Positions and Jaw Clenching Activity on Cycling Performance

The purpose of this study was to identify the effects of three initial crank positions and jaw clenching activities on seated cycling performance. 10 normal subjects (5 females, 5 males) completed six separate occasions of Wingate Test with three different initial crank positions (0°, 47°, 71°) and two modes of jaw activities (jaw clenching and jaw loose). The findings suggest that, crank angle of 71° has the highest power output compare to other angles. The combination of 71° crank angles and jaw loose the jaw shows the best cycling performance

Fracture risk prediction on children with osteogenesis imperfecta subjected to loads under activity of daily living

Children with Osteogenesis Imperfecta (OI) often vulnerable to fracture even on their daily basic tasks. The unpredicted fracture leads to intramedullary surgery. This study aims to investigate the fracture risk in children with OI in daily basic tasks including standing, walking, and jumping. Ten models of OI finite elements were reconstructed based on the radiography CT image of enrolled OI patients. An actual body weight of OI patient was used as the main force acting vertically towards the femoral head and then the fracture risk was observed. In standing and walking configuration, all ten OI models were found able to sustain the acted load. Whereas in jumping configuration, all OI models suffered to become fracture. Early prediction of fracture risk could help medical personnel and OI patients from fall or injury