With there being approximately ½ million hip replacements in the world each year and increasing, I thought that a review based on an article “boning up on materials” would be one of diverse interest.

Materials in replacement of bone must function as well as the natural counterpart and a number of investigations are being carried out today in order to find the perfect bone substitute. It is a complex task to produce a synthetic material that is non-toxic, compatible with other chemical reactions in the body, does not exceed the stiffness of natural bone and does not shed debris as a result of friction.

A material has been created that is almost chemically identical to bone. It has the same density, is compatible and contains the same percentage of hydroxyapatite (a compound containing calcium.) An advantage to this material is that it releases calcium ions to stimulate bone growth on top of the artificial bone. It is so similar to natural bone that it does not show up on X-rays.

These new advances in medical technology increase the life span of replacements by up to 10 years, even at load bearing joints.

The first widely used hip replacement was invented by Sir John Charnley and was called “ The Charnley Prosthesis”.  Built using metal and plastic, this was successful until modern improvements. A danger associated was the polymethylmethacrylate (PMMA) adhesive that caused an exothermic reaction within the body. As a result, nearby bone died and the blood boiled.

Chemistry is part of our every day life! A lot of work goes in behind the scenes of every product, not just bone replacements. Chemistry is not boring! It is made up of simple principles that are important for us to know for our health’s sake, at least.

By Ciara O' Donnell. Chemistry Department, Loreto College, Coleraine.