Articular prosthese

The second risk factor is wear, in particular produced by articular prostheses and mobile, nonstabilized implants generating wear particles by abrasion (Laffargue et al. 

Polymers have become essential in all areas of health, from the solid materials used, for example, for prostheses, catheters and blood bags to the nanosystems developed for the vectorization of active substances and for diagnostics [GAU 03]. Among all these devices, some are single use (syringes, infusion sets, etc.), while others are introduced into the body for a period which is a priori indefinite (articular prostheses, vascular substitutes, artificial crystalline lenses, stitches thread, etc.). 

Conclusions. Results from the biocompatibility studies in rabbit supratellar bursa, measurement of hydrophilic properties, lubrication and wear in-vitro studies, determination of viscoelastic properties, measurement of damping coefficient and impact test, total elbow joint replacement design and in-vivo percutaneous implant experiment, all indicate that this series of polyurethanes is an excellent candidate biomaterial for the prosthetic replacement of articular cartilage, artificial joint prostheses and percutaneous implantable devices. 

Other biomedical applications of polymers include sustained and controlled drug delivery formulations for implantation, transdermal and trans-cornealuses, intrauterine devices, etc. (6, 7). Major developments have been reported recently on the use of biomaterials for skin replacement (8), reconstruction of vocal cords (9), ophthalmic applications such as therapeutic contact lenses, artificial corneas, intraocular lenses, and vitreous implants (10), craniofacial, maxillofacial, and related replacements in reconstructive surgery (I), and neurostimulating and other electrical-stimulating electrodes (I). Orthopedic applications include artificial tendons (II), prostheses, long bone repair, and articular cartilage replacement (I). Finally, dental materials and implants (12,13) are also often considered as biomaterials. 

Wear particles produced by abrasion appear essentially in the vicinity of articular pros-theses and of implants with a certain mobility, for example, uncemented total hip replacements. These wear particles may induce multiple tissue reactions osteolysis, degradation of normal bone structure, severe macrophagic reactions, granuloma, fibrotic capsules, inflammatory and immune reactions which may cause destabilization and loosening of prostheses and implants (Dorr etal. 1990 McKellop etal. 1990 Sarmiento and Gruen 1985 Weiss-man et al. 1991). 

AI2O3 and Zr02 are considered to be nonbioactive ceramics and are frequently used as the articular heads of total arthroplasties such as total hip prostheses, total shoulder prostheses, and maxillar articular replacements. No unwanted biological effects could be observed in vivo, and no cytotoxic effects have been evidenced in vitro for both compounds except for some formation of granuloma around wear particles of these materials. Oonishi et al. (1997) have also shown small amounts of new bone formation between AI2O3 particles in an experimental rabbit femoral defect model. 

Nasser S, Campbell PA, Kilgus D, Kossovsky N and Amstutz HC (1990) Cementless totaljoint arthroplasty prostheses with titanium-alloy articular surfaces. A human retrieval analysis. Clin Orthop Rel Res 261 171-185. 

Willert, H., Semlitsch, M. (1976) Reactions of the articular capsule to joint prostheses. In Biocompatibility of Implant Materials, D.F. Williams (ed.), London, Sector Publishing, pp. 157-169. 

Willert HG. Reactions of the articular capsule to wear products of artificial joint prostheses. J Biomed Mater Res 1977 11(2) 157-64. 

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