Hip Replacement

There are two major types of artificial hip replacements - Cemented Prosthesis and the Uncemented Prosthesis. Both types of prosthesis are widely used.

Each prosthesis is made up of two parts

The acetabular component, or socket portion, which replaces the acetabulum.

The femoral component or stem portion, which replaces te femoral head.
The femoral component is made of a metal stem with a metal ball on the end. Some prosthesis have a metal head on upper end attached to the metal stem. The acetabular component is a metal shell with a plastic inner liner that acts like a bearing. The type of plastic used is highly cross linked ultra high molecule weight Polyethylene which is wear resistant.

A cemented prosthesis is held in place by Poly Metha Acrylate (PMMA) cement that attaches the implant to the bone. An uncemented prosthesis has a fine mesh of holes on the surface area that touches the bone. The bone grows into the mesh and gives a better fixation. The life of uncemented prosthesis is three times as that of cemented hip prosthesis.

The recent advances in the articulating bearing surfaces have brought metal on metal articulation, ceramic on ceramic articulation and metal on ceramic articulation. These implants are readily available and use in our centre.