Materials Used in Orthopaedic Implants

Other Materials

Ceramics

Ceramic materials are usually made by pressing and heating metal oxides (typically aluminum oxide and zirconium oxide) until they become very hard. These ceramic materials are strong, resistant to wear, and biocompatible. They are used mostly to make implant surfaces that rub together but do not require flexibility, as in the surfaces of a hip joint.

Composite Materials

Composite materials are made by mixing two or more separate materials without creating a chemical bond between the materials. For example, carbon fibers may be added to another material to provide additional strength, but the two materials do not combine in a way that creates a new material. Metal alloys and ceramics are not considered to be composite materials because their ingredients are chemically bonded to create a new material.

On a larger scale, two layers of different materials can be combined to create a composite material with the desired characteristics. The stem of a hip implant, for example, may consist of layers of two different materials that together provide the desired combination of strength and flexibility.

Trabecular Metal™ Material

Trabecular Metal material is made from tantalum over carbon. It is strong, flexible, and biocompatible. The structure of Trabecular Metal material is similar to the structure of bone. It is very porous, which means it has small spaces or pores. New tissue can grow into these pores and help hold the implant in place.

Bioabsorbable Materials

Bioabsorbable materials are designed to be absorbed by the body when their job is complete. They are made from a biocompatible plastic that can be dissolved by normal body fluids. Many sutures used today in all types of surgery are bioabsorbable. These bioabsorbable materials may also be used in implants that reattach soft tissue to bone.

Silicone

Silicone is a rubbery material that is very flexible. In orthopaedics, it is most commonly used in implants that replace the joints of the toes.