The purpose of this study is to investigate the feasibility of bone cement as a vehicle of methotrexate, and potent chemotherapeutical drugs for osteosarcoma, and to evaluate the cytotoxic effect of the eluted methotrexate on osteosarcoma cells.

Various amounts of methotrexate were mixed with bone cement to make pellets containing corresponding dosages of methotrexate. The elution experiment was performed. The amount and the rate of elution, the duration of elution, and the elution pattern were checked daily by measuring the absorbance for four weeks. The cytotoxic effect of the eluted methotrexate on SaOS2 and MG63 osteosarcoma cells was examined by MTT assay, and the results were analyzed according to the concentration of the methotrexate and time.

The amount of eluted methotrexate was the greatest during the first day, then the amount decreased rapidly until the end of the first week, reaching its plateau in the third week. The amount of eluted methotrexate from the pellets averaged 6.1% during the first week, and 9.6% during the four weeks. The concentration of eluted methotrexate was 130 to 10,000 times higher than the minimum inhibitory concentration throughout the experimental period. As a result of the cytotoxic effect of the eluted methotrexate, the number of viable tumor cells decreased significantly after 72 hours of exposure, and the viable cells were hardly seen after one week.

In conclusion, the methotrexate eluted from the bone cement has sufficient cytotoxic effect on osteosarcoma cells in vitro, and the results suggest that local chemotherapy using a methotrexate loaded cement may be applicable in the management of osteosarcoma after evaluation of its long-term effect.