Research revealing factors affecting bone cement setting will aid the design of cements with tuneable properties, claim UK scientists.

A team of researchers led by Michael Hofmann at the University of Birmingham used infra-red spectroscopy to monitor the setting reaction of bone cement in real time. 

Bone cement forms brushite on setting, a slightly soluble form of calcium phosphate that is degraded by the body when the bone has healed. Brushite cements harden very quickly, and setting retardants, such as citric acid, are commonly used to slow down the process. 

When Hofmann increased the citric acid concentration, he found that the cement weakened and a calcium phosphate-citrate complex was formed. Weak cements have limited use and cannot be used to heal large, load-bearing bones such as leg bones.  

Jozef Helsen, a materials scientist at the University of Leuven, Belgium, said that although long term clinical testing with these cements is not yet available, the group's work represents a significant step towards to introductory clinical application.

Hofmann's group intends to extend the research to other setting retardants. Their long term plan is to design bone cements with characteristics that can be tailored to the fracture type. They hope to speed up this design with the help of computers.

'A major challenge will be to perform computer simulations based on the experimental results,' said Hofmann. 'By having accurate simulation, we can screen thousands of candidate systems to identify lead compositions for further practical study.'

Joanne Thomson