Injectability evaluation of bone-graft substitutes based on carrageenan and hydroxyapatite nanorods

Abstract

The first injectable bone substitutes were introduced for orthopedic trauma applications since more than a decade, and over recent years the number of commercial products has dramatically increased. These substitutes can be injected into a fracture space for augmentation as an alternative to bone graft, or around a screw for augmentation if the bone is weak, so the injectability of the substitute must be optimum with a good behavior within and our of syringe. The aim of this work was to study the injectability of substitutes based on carrageenan CG with 1, 1.5, 2.5 and 60 wt% hydroxyapatite HA nanorods. Initially carrageenan and hydroxyapatite were characterized and then injectability tests were performed with the syringe between the compression plates of a testing machine. The material also was characterized by scanning electron microscopy. The results revealed that none of the samples had phases separation and they did not exceed 300 N of force (97.08, 107.84 and 149 N to each material), that the injectability was 95.71, 93.69 and 90.63% and the CG was a good vehicle for HA nanorods. Therefore, the substitutes are adequate for manual handling.