Metallic orthopedic implants

Flarm caused by the use of metallic implants is essentially due to the release of ions resulting from the corrosion of these alloys. This concerns principally Ni, Cr and Co for any application. Be, Cd, Pd, Ag and Cu for dental alloys, and Ti for stomatological and orthopedic implants (Flildebrand etal. 1995 Flildebrand and Flornez 1998 Hornez et al. 2002). 

Thus, different criteria must be observed in order to improve the performance of metallic implants and of craniofacial, otologic and orthopedic prostheses (Bischoffetal. 1994) ... 

Filler in bony defects in dental and orthopedic surgery Particles Plasma sprayed coatings on metal implants Particles... 

Hydroxyapatite has been coated on metaUic dental and orthopedic implants by high-temperature plasma thermal spray since the 1980s [24,25]. In this process, HA powders are fed into a plasma flame (temperature 5,000 to 15,000°C). The powders are quickly melted and quenched on the metallic implant substrate to... 

This chapter will not discuss surface modification methods used throughout orthopedic applications not related to polymeric biocomposites. These methods focus on improving the interaction between bulk materials, such as metal implants, and the body through modification of the implant surface. Although this is an important field of smdy, the effects of these forms of surface modification are not applicable to polymeric biocomposites. 

There are various applications for metal implants, including vascular and digestive stents, internal fracture treat-ments, face and dental surgery, and orthopedic joint re-placements. 

This paper focuses on orthopedic devices and related problems, as most published studies investigated orthopedic metal implants [1]. 

Usually, orthopedic metal implants are well tolerated. However, between 3% (e g. hip joint replacement) [2, 3] and 80% (e.g. hand joint replacement in patients with rheumatoid arthritis) [4] of patients develop severe side effects, depending on anatomical location and medical condition. 

Osteoclasts play a major role in bio-corrosion of orthopedic metal implants. Implant-derived metal ions enhance osteoclastic recruitment, maturation, survival and function. The metal ions also induce a peri-implant inflammation with accumulation of various immune cells. The metal ions form complexes with cellular proteins that become new antigens inducing allergenic reactions where T-lymphocytes play an essential role. Those immune cells produce various inflammatory cytokines that cause inflammation and pain. In addition, T-lymphocytes secrete RANK-L, an essential factor for osteoclast functions. Finally, the described mechanisms are probably responsible for a vicious cycle with enhanced peri-implant inflammation and pain, as well as enhanced osteoclastic bio-corrosion and peri-implant bone resorption culminating in implant loosening (Figure 3). 

The next advance in total hip arthroplasty came with the development of various porous surface treatments which allow bone tissue to grow into the metal porous coating on the femoral stem of the hip implant and on the acetabular component of the total joint replacement. These developments arose because of patients who were not able to tolerate cemented implants because of allergies to the cement, methylmethacrylate. More youthflil patients are better served by a press-fit implant as well. Figure 12 shows the difference between textured and beaded surface-treated orthopedic prostheses. 

Orthopedic and dental implant materials bioceramics, 145-146 chemical modifications, 147-148 comparing mechanical properties of, and bone, 146 conventional, 127 costs, 126-127 current materials, 145-148 fate of implanted device, 140-141 integration into surrounding tissue, 127 integrin expression on osteoblasts, 144 integrins, 143-144 metals, ceramics, and polymers, 145 next generation, 127,148-159... 

Nickel allergy is an adverse effect of the use of nickel-containing medical apphances, such as orthopedic metal alloys, dental materials, and implants (9), and allergic reactions are common. Nickel allergy and contact dermatitis with nickel-based apphances have been reviewed (10). 

Titanium is used in medicine mainly for its mechanical benefits in surgical and dental materials in a host of orthopedic and orthodontic appliances, with or without other metals (for example nickel, cobalt, chromium), and generally without serious adverse effects. Titanium and its alloys are in use as implants in bone surgery (1,2) and in dental materials (3,4). Research on the biocompatibility of metal and tissue continues (5). 

Whereas Ti is very abundant in the earth s crust, it is not an essential element, unlike the remainder of the biologically very important first row of transition metals. It is often referred to as the space age metal , on account of its use in strong lightweight alloys for the aerospace industry, as well as in medical prostheses, orthopedic implants, mobile phones, etc., and it also has therapeutic potential in a number of antitumour drugs. Of the other two members, neither Zr nor Hf (the latter named Hafnia after the Latin name for Copenhagen) has any biological importance. 

Corrosion of metallic surgical implant materials used in orthopedic, cardiovascular, and dental devices resulting in the release of metal ions to tissues, and degradation of the physical properties of polymeric implant materials due to interactions with tissue fluids and/or blood... 

Transparency Market Research (2014) Biomaterials Market for Implantable Devices (Material Type - Metals, Polymers, Ceramics and Natural, Applications - Cardiology, Orthopedics, Dental, Ophthalmology and Others) - Global Industry Analysis, Size, Share, Growth, Trends and Forecast, 2013 - 2019. 

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