Metallic implants, orthopedic applications

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). 

Due to their mechanical properties of toughness, high strength, and ductility, metals and their alloys are used for implants in dental and orthopedic applications. However,... 

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. 

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. 

There are extensive studies centering on the fabrication of nanostructured metals in order to improve their mechanical properties. Since mechanical performance of orthopedic implant is critical to its applications, liability and lifetime, superior mechanical properties are always wanted. Depending on clinical settings, the wanted properties include, but are not limited to, enhanced mechanical strengths, toughness, ductility, wear resistance, corrosion resistance, and special characteristics such as superplasticity and shape-memory effect. Due to space limitations, only the typical aspects and examples of implant mechanical properties enhanced by nanotechnology are introduced here. 

Theoretically, anodization can be applied to any metal that is stable to oxide to fabricate nanoscale tubular or porous surfaces. The unique tubular structures in metals can serve as a source of loading bone growth factors or antibiotics to promote bone growth or suppress bacterial infection when released [67-70]. This is a novel application for metals because anodization can transform a metal into a drug delivery device. Importantly, metals are the most common orthopedic implant material and yet, few metaUic drug delivery strategies exist from metals. 

Each type of material has its own advantages that makes it suitable for each specific applications, but it is difficult for a single material to have all the required properties [8]. For instance, ceramics and metals are strong and tough materials suitable for joint replacements as well as dental, bone and orthopedic implants. However, Metals can corrode and are dense, while ceramics are brittle and non-resilient. 

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