ABSTRACT
@#Medical implants are normally used in clinical practice to treat most orthopaedics situations involving bone fractures, deformities, dislocation, and lengthening. It should be noted that specific measures regarding biomechanical and biomaterial characteristics are required for a successful post-surgery procedure. Biomechanical evaluations on the medical implants could be performed by utilising computer and engineering technology. One of them is in silico studies using finite element method that could be simulated in high-performance computer. However, various assumptions are required in computer simulation, such as the constraints on data input and computer resources. This review paper discusses current approaches of constructing a finite element model of human bone with specific material properties for upper limb such as the shoulder joint, humerus, elbow joint, radius and wrist joint. Previous related literatures were reviewed from selected keywords and search engines. To narrow the literature search in this study, inclusion and exclusion criteria of the literature searching were applied. We looked at the current level of knowledge in this field and offered recommendations for future study. In conclusion, studies from previous literature have demonstrated several ways for developing mathematical models and simulating medical implants.
ABSTRACT
@#Introduction: Screws placement may influence the stress distribution and stability of the plate and bone. Implant failures are normally happened in clinical practise when inappropriate number of screws is implemented. Therefore, intensive investigations are needed to provide additional quantitative data on the use of different number of screws. Therefore, this study was conducted to investigate the biomechanical performance of different number of screws configurations on Locking compression plate (LCP) assembly when treating transverse fractures of the tibia bone. Methods: Finite element method was used to simulate tibia bone fracture treated with LCP in standing phase simulation. To accomplish this, a three-dimensional tibia model was reconstructed using CT dataset images. 11 holes of LCP and 36mm of locking screws were developed using SolidWorks software. From this study, there are three models in total have been developed with different number of screws and screw placements. A diaphysis transverse tibia fracture of 4 mm was constructed. Results: In terms of stress distribution, all configurations provide sufficient stress and do not exceeding the yield strength of that material. Conclusion: In conclusion, eight numbers of screws were the optimum configurations in order to provide ideal stability to the bone with displacement of 0.37 mm and 0.91 mm at plate and bone, respectively.
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@#Introduction: Every month, Sports National Institute (ISN) in Malaysia received around 3 to 4 cases associated with anterior cruciate ligament (ACL) injury involving athletes in hockey, kick volleyball and netball. Knee orthosis is one of treatment method and has been shown to support lower limb joint mechanics, which may protect the ACL injury for becoming worst. In this paper, an investigation was conducted to evaluate the performance of existing knee orthosis for treating ACL injury. Methods: Ten participants which have been grouped into two; six ACL patients (Group 1) and four healthy subjects (Group 2), where they took part in two bracing conditions; 1) with hinge (Brace 1) and 2) sleeve with bilateral hinges (Brace 2). A non-braced condition was included as a baseline measure. Three-dimensional kinematics data were used to calculate knee joint motions. Results: From the findings of ACL subjects, the knee flexion in non-braced condition (49.9°) has high value than others two braces, in which Brace 1 (40.9°) is less value than Brace 2 (44.6°). This shows the Brace 2 have higher degree of freedom than Brace 1. Other than that, the comfortability assessment found that Brace 2 is the most favourable options by participants in terms of less slippage and comfortless condition. Conclusion: In conclusion, the Brace 2 give best performance during dynamic balance activity in individuals who benefit from high degree of freedom and less slippage issue.
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@#Introduction: Amputee patients are usually utilized prosthetic leg for daily activities such as walking, climbing, and running. However, the current prosthetic leg that available from the market often associated with poor comfortability due to its conventional way of socket manufacturing. Therefore, this research aims to build custom-made passive transtibial prosthetic legs and to evaluate the aspects of biomechanical analysis. Methods: The residual leg of a subject was scanned using the Sense three-dimensional scanner. By referring to scanned residual leg model, two design of prosthetic legs which are the low-cost solid ankle cushion heel (SACH) foot (D1), and the high-cost flex foot (D2), were developed by using computer aided software (CAD), SolidWorks and Meshmixer. Each of the components were then meshed with triangle edge length of 5 mm in 3-Matic software. Marc.Mentat software was used to simulate the midstance phase of a gait cycle where an axial load of 350 N was applied. Results: The overall maximum stress of the D1 (190.2 MPa) was higher than D2 (38.47 MPa). In addition, socket and pylon in D1 showed tendency to yield because the maximum stress is higher than yield stress of respective materials. In displacement analysis, D2 showed higher overall displacement than D1 because the flex foot has higher flexibility. Conclusion: From overall result, prosthetic leg of D2 is better in biomechanical strength as compared with the D1 because it can withstand the loading from subject’s weight without showing any sign of yield.
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@#Introduction: Detecting breast cancer at earlier stage is crucial to increase the survival rate. Mammography as the golden screening tool has shown to be less effective for younger women due to denser breast tissue. Infrared Thermography has been touted as an adjunct modality to mammography. Further investigation of thermal distribution in breast cancer patient is important prior to its clinical interpretation. Therefore, thermal profiling using 3D computational simulation was carried out to understand the effect of changes in size and location of tumour embedded in breast to the surface temperature distribution at different breast densities. Methods: Extremely dense (ED) and predominantly fatty dense (PF) breast models were developed and simulated using finite element analysis (FEA). Pennes’ bioheat equation was adapted to show the heat transfer mechanism by providing appropriate thermophysical properties in each tissue layer. 20 case studies with various tumour size embedded at two asymmetrical positions in the breast models were analysed. Quantitative and qualitative analyses were performed by recording the temperature values along the arc of breast, calculating of temperature difference at the peaks and comparing multiple thermal images. Results: Bigger size of tumour demands a larger increase in breast surface temperatures. As tumour is located far from the centre of the breast or near to the edge, there was a greater shift of temperature peak. Conclusion: Size and location of tumour in various levels of breast density should be considered as a notable factor to thermal profile on breast when using thermography for early breast cancer detection.