Bone replacement/repair

Carbon fiber composites are replacing screws for bone fracture repair and joint replacements. These fiber composites are equally strong and chemically inert. By comparison, the metals they replace are often alloys, which may contain metals that the patient may be allergic to. 

Allogeneic bone matrix repair, replacement, and/or reconstruction of bone defects... 

Coral is a natural substance made by marine invertebrates. According to Holmes et al. [1984], the marine invertebrates live in the limestone exostructure, or coral. The porous structure of the coral is unique for each species of marine invertebrate [Holmes et al., 1984]. Corals for use as bone implants are selected on the basis of structural similarity to bone [Holmes et al., 1984]. Coral provides an excellent structure for the ingrowth of bone, and the main component, calcium carbonate, is gradually resorbed by the body [Khavari and Bajpai, 1993]. Corals can also be converted to hydroxyapatite by a hydrothermal exchange process. Interpore 200, a coral hydroxyapatite, resembles cancellous bone [Sartoriset al., 1986]. Both pure coral (Biocoral) and coral transformed to hydroxyapatite are currently used to repair traumatized bone, replace diseased bone, and correct various bone defects. 

Bioactive ceramics Bioactive (grows into the bone, etc.), biocompatible Replacement/repair of bones/joints... 

A.J. Wagoner Johnson, B. A. Haschler, A review of the mechanical behavior of CaP and CaP/polymer composites for applications in bone replacement and repair, Acta Biomater. 7 (2011) 16-30. 

Sanderson, J.E. (1988) Bone Replacement and Repair Putp Material from Unsaturated Polyester Resin and Vinyl Pvrrolidone, United States Patent 4,722,948, 1-14. 

Several workers have proposed new combinations of materials in an attempt to overcome wear. Studies involving polyimides, polyamide-imides, and poly-tetrafluoroethylene-filled polyoxymethylene demonstrated that although wear characteristics were good in dry conditions, the presence of lubricants (blood plasma, water) decreased the wear resistance. Results obtained with reinforcing materials such as carbon fibre and with an aluminium oxide ceramic ball used in conjunction with a polyethylene socket have been presented, Examples of other types of reconstructive surgery involving hard tissue replacement are the use of poly(methyl methacrylate) in chest wall reconstruction and repair of depressed skull fractures, the repair of major crano-orbital defects with the aid of a polyurethane-coated poly(ethylene terephthalate) mesh, and the use of silicone rubber in total finger joint and carpal bone replacement. 

Warren, S.M., Fong, K.D., Nacamuli, R.P., Song, H.M., Fang, T.D., Longaker, M.T., 2003. Biomaterials for skin and bone replacement and repair in plastic surgery. Oper. Tech. Plast Reconstr. Surg. 9, 10-15. 

Tantalum is completely inert to body fluids and tissues. Bone and tissue do not recede from tantalmn, and this biocompatibility makes it an attractive material for body and dental implants. However, the superior strength and rigidity of stainless steel and titanimn and the castabUity of high-cobalt alloys have led to their greater use for prosthetic devices. Tantalmn has nevertheless been used for bone replacement and repair, for cranial repair plates, suture wire, and wire gauze for abdominal muscle support in hernia smgery. ... 

Witte, F., Reifenrath, J., Muller, P. P., Crostack, H.-A., Nellesen, J., Bach, F. W., Bormann, D. Rudert, M. (2006d) Cartilage repair on magnesium scaffolds used as a subchondral bone replacement. Mat.-wiss. u. Werkstofftech, 37, 504-8. 

A rapidly growing use in the medical field is for surgical implants as either bone plates and screws, joint replacements, or for the repair of cranial injuries. Here, titanium and its alloys have the advantages of complete compatibility with body fluids, low density, and low modulus. Applications also exist in dentistry. 

Under normal circumstances, the skeleton undergoes a dynamic process of bone remodeling. Bone tissue responds to stress and injury through continuous replacement and repair. This process is completed by the basic multicellular unit, which includes both osteoblasts and osteoclasts. Osteoclasts are involved with resorption or breakdown of bone and continuously create microscopic cavities in bone tissue. Osteoblasts are involved in bone formation and continuously mineralize new bone in the cavities created by osteoclasts. Until peak bone mass is achieved between the ages of 25 and 35, bone formation exceeds bone resorption for an overall increase in bone mass. Trabecular bone is more susceptible to bone remodeling in part owing to its larger surface area. 

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