University researchers may hold key to the future of joint replacement

15 September 1998
Researchers at Waikato University are conducting research into the use of dried animal bones for use as joint replacements in humans. 

The research involves using the hip bone out of cows, cutting it into cubes, and then putting it through a rigorous extraction process to ensure purity. It is then soft enough for doctors to cut it into the shape of a joint for insertion into humans. 
The bone can also be used in a powder form which can be sprayed onto other materials that are traditionally surgically implanted into the body, including titanium based materials that are often used in hip joint replacements. 
The research is the only of its kind in New Zealand, and involves additional national and international collaboration with Industrial Research Ltd in Auckland and Chemnitz Technical University in Chemnitz, Germany. 
Dr Michael Mucalo, from the University’s Chemistry Department, thinks that the potential benefits of the work for advances in restorative and corrective surgery are considerable.
“The bone could be used as a hard tissue replacement in non-load bearing areas of the body, for example, for correcting nose deformities, or for filling cavities created by destruction of bone by cancer,” says Dr Mucalo.
“Powdered bone can also be prepared and used as a ‘plasma spray-coating’, which can be attached to ceramic or titanium plates for implantation, and this helps the body to accept the implant.”
The bone from cows is used because it is more ‘biocompatible’ than other materials - it is less likely than metal and ceramic to be rejected by the body because it is closer to the human body’s chemistry. The research also makes use of what has traditionally been a waste product, said Dr Mucalo.
The research up until now has been concentrated on the processing of the bone tissue. In the future, Dr Mucalo will look at applications of the bone matter, through experimental implantation and tests on the plasma spray and the potential of the materials to act as a controlled release drug delivery system, or as enzyme carriers.
The research began in 1996 as a collaborative project between the University of Waikato, Department of Chemistry (Dr Michael Mucalo) and MIRINZ Food Technology and Research Ruakura (Mr Michel A Lorier). University Masters student, Glenn Johnson, undertook the initial experimental phase of the project from 1996-1998 as part of his Masters thesis in Chemistry.
The project is being funded by the Foundation for Research in Science and Technology for a period of four years between 1996 and the year 2000.