Abstract
Recently, the osteoregenerative properties of allograft have been enhanced by addition of autogenous skeletal stem cells to treat orthopaedic conditions characterised by lost bone stock. There are multiple disadvantages to allograft, and trabecular tantalum represents a potential alternative. This metal is widely used, although in applications where there is poor initial stability, or when it is used in conjunction with bone grafting, loading may need to be limited until sound integration has occurred. Strategies to speed up implant incorporation to surrounding bone are therefore required. This may improve patient outcomes, extending the clinical applications of tantalum as a substitute for allograft.
Aim
To use tissue engineering strategies to enhance the reconstructive properties of tantalum, as an alternative to allograft.
Methods
Human bone marrow stromal cells (5×105 cells/ml) were cultured on blocks of trabecular tantalum or allograft for 28 days in basal and osteogenic media. Molecular profiling, confocal and scanning electron microscopy, as well as live/dead staining and biochemical assays were used to detail cell adherence, proliferation and phenotype.
Results
Cells displayed extensive adherence and proliferation throughout trabecular tantalum. Samples cultured in osteogenic conditions showed abundant matrix production. Electron microscopy confirmed significant cellular growth through tantalum to a depth of 5mm. In contrast to cells cultured with allograft in both basal and osteogenic conditions, cell proliferation and biochemical assays showed significantly higher activity with tantalum than allograft. Furthermore, alkaline phosphatase (ALP) assay and molecular profiling confirmed no significant difference in expression of ALP, Runx-2, Col-1 and Sox-9 between cells cultured on tantalum and allograft.
Conclusions
These studies demonstrate trabecular tantalum supports cell growth and osteogenic differentiation at least as well as allograft. Trabecular tantalum represents a good alternative to allograft for tissue engineering osteoregenerative strategies in the context of lost bone stock. Further mechanical testing and in vivo studies are on-going.
