Oxinium
Encyclopedia
Oxinium is the brand name of a material used for replacement joint
s manufactured by the reconstructive orthopedic surgery
division of medical devices company Smith & Nephew
. It consists of a zirconium
alloy
metal substrate that transitions into a ceramic zirconium oxide outer surface.
The ceramic surface is extremely abrasion resistant compared to traditional metal implant materials such as cobalt chromium. It also has a lower coefficient of friction against ultra-high molecular weight polyethylene (UHMWPE), the typical counterface material used in total joint replacements. These two factors likely contribute to the significantly lower UHMWPE wear rates observed in simulator testing. Reducing UHMWPE wear is thought to decrease the risk of implant failure due to osteolysis
. All-ceramic materials can have a similar effect on reducing wear, but are brittle and difficult to manufacture. The metal substrate of Oxinium implants makes components easier to manufacture and gives them greater toughness (a combination of strength and ductility). In essence, this technology combines the abrasion resistance and low friction of a ceramic with the workability and toughness of a metal.
This combination of properties led to Oxinium technology being the first ever implant-related technology to win the prestigious ASM International
Engineering Materials Achievement Award (EMAA) in 2005.
Current competitive reduced-wear options in total hip arthroplasty
(THA) are ceramic
-on-ceramic, metal
-on-metal, and metal-on-cross-linked polyethylene
. The only competitive reduced-wear option for total knee arthroplasty
(TKA) is metal-on-cross-linked polyethylene.
In September 2003, Smith & Nephew recalled its Macrotextured Oxinium Profix and Genesis II knee implants because of reports that 30 people receiving the implants without bone cement had to undergo a replacement surgery after they became loose.
Replacement joint
Replacement arthroplasty [from Greek arthron, joint, limb, articulate, + -plassein, to form, mould, forge, feign, make an image of], or joint replacement surgery, is a procedure of orthopedic surgery in which the arthritic or dysfunctional joint surface is replaced with an orthopaedic prosthesis...
s manufactured by the reconstructive orthopedic surgery
Orthopedic surgery
Orthopedic surgery or orthopedics is the branch of surgery concerned with conditions involving the musculoskeletal system...
division of medical devices company Smith & Nephew
Smith & Nephew
Smith & Nephew plc is a global medical devices company headquartered in London, United Kingdom. It is the world's largest producer of arthroscopy products, second-largest producer of advanced wound management products, third-largest producer of trauma and clinical therapy products and...
. It consists of a zirconium
Zirconium
Zirconium is a chemical element with the symbol Zr and atomic number 40. The name of zirconium is taken from the mineral zircon. Its atomic mass is 91.224. It is a lustrous, grey-white, strong transition metal that resembles titanium...
alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
metal substrate that transitions into a ceramic zirconium oxide outer surface.
The ceramic surface is extremely abrasion resistant compared to traditional metal implant materials such as cobalt chromium. It also has a lower coefficient of friction against ultra-high molecular weight polyethylene (UHMWPE), the typical counterface material used in total joint replacements. These two factors likely contribute to the significantly lower UHMWPE wear rates observed in simulator testing. Reducing UHMWPE wear is thought to decrease the risk of implant failure due to osteolysis
Osteolysis
Osteolysis refers to an active resorption of bone matrix by osteoclasts as part of an ongoing disease process.-Osteolysis in joint replacement:...
. All-ceramic materials can have a similar effect on reducing wear, but are brittle and difficult to manufacture. The metal substrate of Oxinium implants makes components easier to manufacture and gives them greater toughness (a combination of strength and ductility). In essence, this technology combines the abrasion resistance and low friction of a ceramic with the workability and toughness of a metal.
This combination of properties led to Oxinium technology being the first ever implant-related technology to win the prestigious ASM International
ASM International
ASM International, formerly known as the American Society for Metals, is a professional organization for materials scientists and engineers working with metals....
Engineering Materials Achievement Award (EMAA) in 2005.
Current competitive reduced-wear options in total hip arthroplasty
Hip replacement
Hip replacement is a surgical procedure in which the hip joint is replaced by a prosthetic implant. Hip replacement surgery can be performed as a total replacement or a hemi replacement. Such joint replacement orthopaedic surgery generally is conducted to relieve arthritis pain or fix severe...
(THA) are ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
-on-ceramic, metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
-on-metal, and metal-on-cross-linked polyethylene
Polyethylene
Polyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...
. The only competitive reduced-wear option for total knee arthroplasty
Knee replacement
Knee replacement, or knee arthroplasty, is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve the pain and disability of osteoarthritis. It may be performed for other knee diseases such as rheumatoid arthritis and psoriatic arthritis...
(TKA) is metal-on-cross-linked polyethylene.
In September 2003, Smith & Nephew recalled its Macrotextured Oxinium Profix and Genesis II knee implants because of reports that 30 people receiving the implants without bone cement had to undergo a replacement surgery after they became loose.