The influence of tantalum on human cell lineages important for healing in soft-tissue reattachment surgery: an in-vitro analysis

BACKGROUND: Porous tantalum is currently used in orthopaedic surgery for a variety of indications including soft tissue re-attachment. However, the clinical results have been variable and a previous laboratory study has suggested that tantalum may actually inhibit chick tendon fibroblasts. The influence of tantalum on human cell-types involved in soft tissue re-attachment has not been defined. METHODS: Human fibroblasts, human osteoblasts and human mesenchymal stem cells were plated on glass cover slips, half of which were coated with tantalum. Cell numbers were assessed at 1, 2, 7 and 14 days using Cyquant® assay. Cell adhesion and morphology were assessed using light microscopy at 7, 14 and 28 days. To reduce the effect of an expected rate of error, n = 4 was utilised for each cell type and the experiment was repeated twice. RESULTS: Statistically similar numbers of human osteoblasts and human mesenchymal stem cells were present at 14 days on tantalum-coated and uncoated glass cover slips, revealing no inhibitory effect on cell proliferation. More than double the number of human fibroblasts was seen on tantalum-coated cover slips at that time point (compared to controls), which was statistically significant (p < 0.0001). Morphological assessment revealed normal cell spreading and adhesion on both substrates at all time points. CONCLUSIONS: In vitro study demonstrates that Tantalum causes a significant increase in the proliferation of human fibroblasts with no quantifiable negative effects seen on fibroblast behaviour after 28 days culture. Furthermore, tantalum does not exert any inhibitory effects on the proliferation or behaviour of human osteoblasts or human mesenchymal stem cells. Tantalum could be an appropriate biomaterial for use in situations where soft tissue requires direct reattachment to implants and may stimulate soft tissue healing.