Comparison of bone healing by demineralized bone matrix and autogenous cancellous bone in horses.

This study sought to examine how bone healing in horses is impacted by using either demineralized bone matrix (DBM) or an autogenous cancellous bone graft (ACB), as compared to not grafting at all (control). The study found that neither DBM nor ACB significantly promoted bone healing in the model studied, suggesting that these grafting methods may not be effective in promoting bone healing in horses.

Objective and Methodology

• The research aimed to compare the rates of bone healing in horses undergoing different treatments – utilisation of a demineralized bone matrix (DBM), an autogenous cancellous bone graft (ACB), or no graft at all as a control group.
• To conduct this study, circular defects of 19mm were created in the exterior cortex of the 6th and 8th rib. Eight mature horses served as an experimental unit with treatments randomly assigned to the three rib defects, while the fourth defect received a random treatment.

Results and Observation

• Two months after the application, researchers observed that all the rib defects led to fractures classified as nonunion fractures. Nonunion fractures are broken bones that don’t heal or where the healing process is inordinately slow.
• The study did not find any significant variance between the three varying treatments in terms of bone mineral density and indications of radiographic or histological healing.
• The rib defects treated with DBM were observed to have less volume of bone, as well as a lower percentage of ash and calcium compared to those treated with control and ACB. This finding suggests that the DBM treatment may have been less effective at promoting bone healing than the other treatments.
• Interestingly, the DBM did not provoke any inflammatory response, and the process of bone remodeling was evident in the decalcified particles’ periphery and vascular channels.

Conclusions

• The researchers concluded that the DBM particles remodel from the periphery, which could account for the significantly lower percentage of ash, calcium, and bone when compared with ACB. In other words, DM particles might behave as space-occupying masses until completely mineralized.
• The study found no evidence that the application of DBM enhances the healing process in the given model.
• The research advised against using 2 to 4 mm DBM particles as these may inhibit normal mineralization, and thus obstruct fracture repair.
• Despite these findings, the researchers suggest that their model of nonunion fracture healing may prove useful for future studies.