Times of India
02 February 2011
By Revathi Ramanan
Chennai, India

For young people with active lifestyles, chronic arthritis and knee replacement could really tie them down. But there’s new hope as doctors have started using oxinium knee implants over the last couple of months.

Traditional knee implants – made of a metallic alloy, cobalt chrome, or of stainless steel – wear out in about 15 years, while the new oxinium implants last twice as long.

Oxinium is an alloy of zirconium that has been processed to absorb oxygen so that there is a ceramic layer on the surface. The resulting material incorporates best features of both ceramic and metal, while avoiding disadvantages of both.

Doctors say that an oxinium implant has metal, which makes it unbreakable, and ceramic that makes movement smoother. It is almost 4,900 times more abrasion–resistant than the traditional metal implants. "The failure of traditional implants is because of scratches on the surface and wear and tear from long–term use.

Oxinium implants have zero friction and are highly abrasion–resistant making them very attractive for younger patients," said Dr S Nandakumar, senior consultant orthopaedic surgeon at Fortis Malar. The oxinium implants reduce friction between the plastic component that acts as cartilage thereby minimising wear and tear. "Friction might result in loosening of the prosthesis but this does not happen with oxinium implants," he said.

One of the main advantages of oxinium implants is its longevity, ideal for patients in their late thirties and early forties. "These implants have been tested and approved by the United States Food and Drug Administration (USFDA) and can last for at least 30 years," said Dr Nandakumar. The implants have been used in the US from 2009.

They can be used in people who suffer from arthritis, have complete wear–and–tear of joint, damaged cartilage and irreparable bone–to–bone rubbing.

He also said that these implants are ideal for patients who are sensitive to metal. The traditional cobalt chrome implants have high quantities of nickel, but oxinium implants have almost no nickel content. The main disadvantages, though, is the prohibitive cost of these implants. "A cobalt chrome implant would cost around Rs 60,000 to Rs 70,000, while the oxinium implants are three times more expensive," said Dr Leonard Ponraj, orthopaedic surgeon at Prashanth Hospitals.

He also said that the implants are fairly new and hence it was difficult to come to any conclusion about their longevity.

Knee–Deep Trouble

• Traditional knee implants – made of a metallic alloy, cobalt chrome, or of stainless steel – wear out in about 15 years, while the new oxinium implants last twice as long
• Oxinium is an alloy of zirconium that has been processed to absorb oxygen so that there is a ceramic layer on the surface. The resulting material incorporates best features of both ceramic and metal
• An oxinium implant has metal, which makes it unbreakable, and ceramic that makes movement smoother