Prosthetic Applications

Carbon fiber has found many uses in biomedical applications [109-139]. 

Roland Christensen established Applied Composite Technology, a company that makes artificial feet, marketed as Flex-Foot, that uses carbon fiber epoxy prepreg, which was so effective that a sports event participant with an artificial foot ran the 100 m in 11.3 s in the 1996 Atlanta Paralympic Games. These artificial feet are sold throughout the world and production has exceeded some 20,000 [140]. 

Braided carbon fiber is used by Ossur, an Icelandic company, to manufacture a custom fitted socket for an artificial limb, enabling the sock to conform to the changing contour of the socket. The braid is pre-impregnated with a water-activated polyurethane resin and sealed in a watertight package. When required, the prosthetist places a silicone sleeve over the limb (below the knee), activates the resin with water, positions the wet braid over the silicone sleeve and the resin sets in about 4 min, achieving a 90% cure in 45 min. 

A Blatchford Sons in the UK, market a wide range of prosthetic devices and in the late 1970s, introduced carbon fiber into their prosthetic devices. The cfrp used in their Endolite equipment possessed superior strength, fight weight and was easily formed to difficult shapes. 

Huettner [141] discusses the role of carbon fiber composites in state-of-the-art ceramics in surgery, such as reinforced carbon shaft endoprosthesis, and finds that cfrp is suitable for the construction of endoprosthesis shafts having high static and dynamic strength. Claes [142] describes experimental investigations on hip prostheses with carbon fiber reinforced carbon shafts with ceramic heads, finding cfrp more suitable than stainless steel. 

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Kokubo, T., Shigematsu, M., Nagashima, Y., Tashiro, M., Nakamura, T., Yamamuro, T. and Higashi, S. (1982) Apatite- and wollastonite-containing glass-ceramics for prosthetic application. Bulletin of the Institute for Chemical Research, Kyoto University, 60, 260-268. 

At present a few studies of nanofibers and nanombes are focused on CNS drug delivery. One study evaluated electrospun nanofibers of a degradable polymer, PLGA, loaded with antiinflammatory agent, dexamethasone, for neural prosthetic applications (Abidian and Martin, 2005). A conducting polymer, poly(3,4-ethylenedioxythiophene), was deposited to the nano-fiber surface and the coated nanofibers were then mounted on the microfabricated neural microelectrodes, which were implanted into brain. The drug was released by electrical stimulation that induced a local dilation of the coat and increased permeability. 

Abidian M, Martin D (2005) Controlled Release of an Anti-Inflammatory Drug Using Conducting Polymer Nanotubes for Neural Prosthetic Applications. In MRS Symposium M, p 1. San Francisco. 

Akao M, Aoki H, Kato K (1981) Mechanical properties of sintered hydroxylapatite for prosthetic applications. J Mater Sci 16 809-812... 

Beta 21-S. The Beta 21-S alloy is a relatively new metastable beta alloy (Ref 1). It was designed to have good formability, similar to Ti-15-3, but also has improved oxidation resistance, creep resistance, and high-temperature strength relative to Ti-15-3. Composition ranges and room-temperature tensile properties for Beta 21-S are listed in Tables 7.1 to 7.3. The alloy contains approximately 15% Mo, 3% Al, and 2.8% Nb, with additions of silicon (Ref 1). It is normally provided in the beta solution-treated condition. Beta 21-S has an elastic modulus close to that of bone and hnds use in prosthetic application. It has excellent high-temperature stability and can be used at temperatures up to 290 °C (550 °F). 

The benefit of being able to sense deflections, generate energy, and modulate stiffness may have substantial impacts on the use of dielectric elastomers as artificial muscles in robotic and prosthetic applications. The DE elements could act as artificial analogs of natural muscle, sensory systems, and digestive systems. A robot consisting of DE elements should therefore someday be capable of controlled motion without the need for additional sensors, and self-sustainability without requiring and an external source of electricity. 

Atkinson J.R., and R.Z. Cicek. 1983. Silane cross-linked polyethylene for prosthetic applications. Part I. Certain physical and mechanical properties related to the nature of the material. Biomaterials 4 267-275. 

The design of solid-state actuator systems that can be incorporated into wearable fabric structures is one of growing interests both as a rehabilitation tool and biomechanical augmentation device. The use of TCP fibers that can be incorporated into textile structures as a sensor or actuating device for prosthetic applications has been reviewed previously [148]. 

DESIGN OF ARTIFICIAL ARMS AND HANDS FOR PROSTHETIC APPLICATIONS... 

The major attraction of pneumatic systems for prosthetics applications is their inherent compliance, which tends to give these systems a very natural look and feel. While pneumatic systems did find some measure of success in prosthetics, hydraulic systems did not. Hydraulics tended to be messy, with hydraulic units leaking hydraulic fluid. In addition, a fluid reservoir and fluid are required, adding to the total weight of the mechanism. 

T. Kokubo, Mechanical Properties of a New Type of Glass-Ceramic for Prosthetic Applications, in Multiphase Biomedical Materials, T. Tsuruta and A. Nakajima, eds, VSP, Utrecht, Netherlands, 1989. 

M. Akao, H. Aoki, and K. Kato, Mechanical Properties of Sintered Hydroxyapatite for Prosthetic Applications, 7. Mater. Sci. 16, 809-812 (1981). 

M. Jarcho, R.L. Salsbury, M.B. Thomas and R.H. Doremus, Synthesis and Fabrication of p-tricalcium Phosphate (Whitlockite) Ceramics for Potential Prosthetic Applications, J. Mater. Sci. 14, 142-150 (1979). 

M. Akao, M. Aoki, K. Kato and A. Sato, Dense Polycrystalline 3-tricalcium Phosphate for Prosthetic Applications, J. Mater. Sci. 17, 343-346 (1932). 

Prosthetic applications for the foot have been primarily rigid in design, with little if any movement. Traditionally prosthetic feet were made from leather, metal, plastic, or a combination of such materials. Modern foot prostheses has improved, with computer-controlled components designed to handle the user s weight and the return of his or her momentum. Such products have been reported to be comfortable enough for participation in rec-... 

The largest voliune of polsrmeric materials used in dentistry is in prosthetic applications. Polymeric materials are also important in operative dentistry, being used to produce composite resins, dental cements, adhesives, cavity liners, and as a protective sealant for pits and fissures. Elastomers are employed as impression materials. Resilient prosthetic devices are oft en fabricated to restore external soft-tissue defects. Mouth protectors are fabricated to prevent injury to teeth, as well as prevent head and neck injinaes. Other polymer applications include fabricating patterns for metal castings and partial denture frameworks, impression trays, orthodontic and periodontal devices, space maintainers, bite plates, cleft palate obdurators, and oral implants. Polymeric materials may also be used to fabricate an artificial tongue, when disease results in its loss. 

Kokubo T, Shigamatsu M., Nagashima Y., Tashiro M., Nakamura T, Yamamuro Y., and Higashi S., "Apatite and Wollastonite-Containing Glass-Ceramics for Prosthetic Application," Bull Inst. Chem. Res., Kyoto Univ., 60, 260-68 (1982). 

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