Stress Distribution and Stability Evaluation of Difference Number of Screws for Treating Tibia Transverse Fracture: Analysis on Patient-Specific Data

@#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.

Patient-Specific Design of Passive Prosthetic Leg for Transtibial Amputee: Analysis Between Two Different Designs

@#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.