Fracture in human bone leads to a pain and reflex injury involving bone and surrounding tissues. Fracture fixation known as bone implants used in healing process of bone fracture and crack. The clinically fixation is used to stabilize the fractured bone, to enable fast healing of the injured bone, and to return early mobility and full function of the injured extremity. After repair phase, there are disturbance as well as pain and reflex immobilization, therefore cause the implant failure. Screw self-loosening of internal fixator is a type of implant failure which is caused by a number of parameters such as dimensions and shape of the plate, separation between screw fittings, stiffness of the plate and screws, damping nature of the surrounding tissue and flexibility of the fracture site. This study aims to develop a dynamic measurement method to analyse screw self loosening mechanism. Loosening of screw implant is caused by septic and aseptic loosening. This studies focus on aseptic loosening as a work analysis which caused by the micro gap between the screw and bone interface. If the screw loosening can be detected at early stage of fixation, the risk of re-surgical operation can be reduced. This study involved the development of a non-invasive technique for detecting screw self loosening in internal fixation. The main objective of this research is to investigate the screw self-loosening detection for internal fixation using the electromagnetic method. An electromagnetic can be induced in a ferromagnetic screw material where the sensor positioned over the fracture site. The strength of the field is necessary to excite the screw, the conductivity and permittivity of the surrounding tissue and the separation between the screw and the sensor. Finite element development model for bone and implant is executed with the integration of Magnetic Induction Spectroscopy (MIS) and electromagnetic based approached. Single channel magnetic induction with one transmitter and one receiver with supplied current of 1A and 0.5A is employed. The induction field was generated at frequency of 1 MHz to 10 MHz from transmitter used to penetrate into the bone and implant, which then received at the receiver. The screw material is made by stainless steel which a hard ferromagnetic material, thus it respond better to a rapidly varying magnetic field than a soft material. The MIS technique was applied to various model of bone implant to differentiate the received total signal changed. The simulation process of this study was executed in COMSOL Multiphysics version 5.2a software. The simulation initiated by investigating magnetic field reaction with biological tissues. Our analysis shows the magnetic field changes when excites through different passive electrical properties (PEP) of biological tissues. The main analysis shows a strong correlation between bone implant gap interfaces (BIGI) model with the total signal of magnetic field. The magnetic field result shows the different value for each conductivity and permittivity detected from the receiver for each BIGI model. The loosening of screw was analysed based on the magnetic field by indicates the range of loosening occur above 100um of microgap due to high strains in the screw and bone interface. Thus MIS system was able in detecting screw-self loosening of internal fixation with 10MHz frequency as an operating frequency.
