Liam Grover and Jake Barrelet from McGill University in Canada, in collaboration with scientists from Germany and the UK, have made and studied a new bone grafting cement that is stronger and sets more slowly than previous cements. Surgeons currently have to prepare very dilute mixtures in order to be able to work with the cement before it sets. This dilution means that the final grafts are less dense and are moderately weak. 

They studied the mixture of beta-tricalcium phosphate and pyrophosphoric acid at various temperatures using X-ray diffraction and found that the acid inhibits crystal growth by coating small crystals. Slowing the growth also leads to smaller crystals which are able to pack with less space between them, giving a denser and stronger material.

Jim Elliott, Deputy Director of the Interdisciplinary Centre in Biomedical Materials at Queen Mary, University of London, said that he thought the work was 'an ingenious new design of calcium phosphate cement, worthy of serious further study'.

Grover commented that 'predicting degradation rates.would truly accelerate developments in the field and likely open routes to new generations of implants'.  However, while currently used cements are almost strong as bone under compression, more work is required to make them more resilient to fractures.

Neil D Withers