7 research outputs found
Stem diameter and rotational stability in revision total hip arthroplasty: a biomechanical analysis
BACKGROUND: Proximal femoral bone loss during revision hip arthroplasty often requires bypassing the deficient metaphyseal bone to obtain distal fixation. The purpose of this study was to determine the effect of stem diameter and length of diaphyseal contact in achieving rotational stability in revision total hip arthroplasty. METHODS: Twenty-four cadaveric femoral specimens were implanted with a fully porous-coated stem. Two different diameters were tested and the stems were implanted at multiple contact lengths without proximal bone support. Each specimen underwent torsional testing to failure and rotational micromotion was measured at the implant-bone interface. RESULTS: The larger stem diameter demonstrated a greater torsional stability for a given length of cortical contact (p ≤ 0.05). Decreasing length of diaphyseal contact length was associated with less torsional stability. Torsional resistance was inconsistent at 2 cm of depth. CONCLUSION: Larger stem diameters frequently used in revisions may be associated with less diaphyseal contact length to achieve equivalent rotational stability compared to smaller diameter stems. Furthermore, a minimum of 3 cm or 4 cm of diaphyseal contact with a porous-coated stem should be achieved in proximal femoral bone deficiency and will likely be dependent on the stem diameter utilized at the time of surgery
Biomechanical Comparison of the Fixation after Curved Periacetabular Osteotomy Using Titanium and Bioabsorbable Screws
Impaction bone grafting with freeze-dried irradiated bone. Part I. Femoral implant stabilityCadaver experiments in a hip simulator
Application and evaluation of biomechanical models and scores for the planning of total hip arthroplasty
Implantable sensor technology: measuring bone and joint biomechanics of daily life in vivo
Flexible Electrode for Implantable Neural Devices
The function of neural electrodes is to interface with the neural system for both sensory and actuation purposes. One of the major challenges in neural devices is to achieve a precise and reliable neuron–electrode interface (NEI). Advances in microfabrication technologies create the possibility to increase the number and reduce the size of electrode sites which can improve the spatial resolution of the NEI. Alternatively, replacing the substrate material of the microfabricated neural electrode from the rigid silicon to the flexible polymer can minimize the stiffness mismatch between electrodes and neural tissue, thus potentially improving the reliability of NEI. In this chapter, we provide an overview of the recent development in microfabricated polymeric neural electrodes. At first, we give a summary of material properties and fabrication processes for some polymers commonly used in the neural electrode application. Then, we review various designs of polymeric neural electrodes in the context of their specific applications. Finally, challenges and corresponding strategies in the development and practicability of polymeric neural electrodes are discussed. © Springer Science+Business Media New York 2014.1