The paralysed knee
Benjamin Joseph, Selvadurai Nayagam, Randall Loder, Ian Torode in Paediatric Orthopaedics, 2016
A floor-reaction orthosis (FRO) (Figure 55.4a) or a knee-ankle–foot orthosis (KAFO) with a knee lock (Figure 55.4b) can be used to stabilise the knee. Carbon-composite orthoses are much lighter that traditional metal and leather orthoses and this reduces the energy expenditure while walking.3 The FRO has the advantages of leaving the knee unlocked during the swing phase of gait and permitting knee flexion while sitting down without having to manipulate a knee lock.4
Achilles tendon rupture
Maneesh Bhatia in Essentials of Foot and Ankle Surgery, 2021
Nonoperative management is only be indicated in low-demand patients or in those who cannot tolerate surgery. In those cases, a carbon composite ankle-foot orthosis may allow for keeping the foot up during swing phase, a soft heel strike, and stability in stance and a better toe-off.
The effect of Knee-Ankle-Foot orthosis stiffness on the parameters of walking
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2018
Sayed Mohammad Ali Abtahi, Nima Jamshidi, Aram Ghaziasgar
It is impossible to enhance the energy storage capacity of carbon by using carbon composite materials. Such a design would improve the strength of the orthosis, resulting in a lighter device. As a result, the upper level in the dynamic response is optimized and the energy return in the third rocker is significantly increased (Danielsson and Sunnerhagen 2004; Wolf et al. 2008; Bregman et al. 2012). The energy cost of walking is obtained by measuring the oxygen consumption (Bleyenheuft et al. 2008). The accurate model in human walking based on anthropometric variables can be adapted to reach a reliable biomechanical model of human body. The net force and the net torque resulting from the performance of the muscles that lead to a specific movement are considered by this model. These variables are not directly measurable. The force of each muscle is obtained by a mathematical model of the muscle (Jamshidi et al. 2009a, 2009b).
An insight into Transfemoral Prostheses: Materials, modelling, simulation, fabrication, testing, clinical evaluation and performance perspectives
Published in Expert Review of Medical Devices, 2022
K. Amudhan, A. Vasanthanathan, J. Anish Jafrin Thilak
Composites are durable and light in weight and are fabricated by joining layers of reinforcement fibers like fiberglass, nylon or carbon. The fibers are tough, malleable, and brittle. Fiber and resin mixture is vacuum-molded onto residual limb models. Wet laminations are made by mixing resins and hardeners and pouring them over the fibers. High heat hardens thermosets. These acrylic, epoxy and polyester composites can be manufactured in various thicknesses for use in sockets. Unlike thermoplastics, thermoset polymers are difficult to reshape after manufacture. The kind, quantity, and combination of fibers and resins can be tailored to a patient’s weight and activity level. Polymer matrix composites are simpler, less expensive alternatives to steel, high-grade Aluminum, Titanium, and Magnesium, especially for applications that require less weight without compromising strength [59,60]. Ionomeric polymer metal composites (IPMC) [61] are cationic capacitive actuators and sensors. They are operated actively due to ionic redistribution in response to imposed electric field or physical deformation. In a prosthetic limb, IPMC material works as an artificial muscle, with actuation controlled by electric impulses. Large electrically induced bending, mechanical flexibility, low excitation voltage, low density and ease of production make IPMC appealing electro-active polymer actuation materials. The most crucial advancement in patient comfort is in socket material technology. Silicone and urethane are used to cushion sockets and prevent skin irritation. Gel liners preserve and cushion the residual limb’s bony prominence [32,34]. Silicone gel, Silicone elastomers, and urethane are the most common materials utilized for liners [33]. Extra-long silicone and PVC gloves are supplied for a smooth transition over the proximal socket brim. Table 1 shows the common reinforcement and matrix materials in polymer matrix composites to fabricate lower limb prosthetic components. All of these papers use respective American Society for Testing and Materials standards (ASTM) to study mechanical parameters including tensile strength, Young’s modulus, and fatigue strength. The number of layers, thickness, layer placement, and volume fraction determines the characteristics of fiber reinforced composites. In fact, most research focuses on producing the socket component using composites and most prosthetic foot components rely on Carbon fiber reinforced polymers (CFRP) composites for their excellent mechanical qualities. Carbon fibers were created in the twentieth century while seeking for a lighter load bearing material. It is known for its high specific strength, specific modulus, high stiffness, and tensile strength. It was determined that it could support a hefty amputee. The specific modulus of Carbon fiber reinforced composites is roughly three times higher than common materials used for prosthetics [62,63]. CFRP also offer high specific tensile and compressive strengths, as well as excellent elastic deformation responsiveness.
Related Knowledge Centers
- Carbon Fibers
- Carbon Nanotube
- Epoxy
- Polyester
- Polymer
- Silica Gel
- Fibre-Reinforced Plastic
- Thermosetting Polymer
- Thermoplastic
- Fiberglass