A novel resorbable strontium-containing α-calcium sulfate hemihydrate bone substitute: a preparation and preliminary study.

Distraction osteogenesis after aggrieved bone segment resections is promising in the treatment of bone tumors and osteomyelitis. However, there is ambiguity with regard to the optimal choice of bone substitute, with biodegradability and excellent bone repair performance constituting key requirements. The purpose of this study was to develop a novel resorbable strontium-containing α-calcium sulfate hemihydrate (Sr-CaS) bone substitute to provide an alternative option for surgeons that better meets these requirements. The Sr-CaS was prepared using co-precipitation and hydrothermal methods and analyzed using x-ray diffraction (XRD), Fourier transform infrared (FTIR) scanning and thermogravimetric differential scanning calorimeter (TG-DSC) patterns. Cytotoxicity by tetrazolium bromide (MTT), sub-acute toxicity and hemolysis tests were performed to assess the initial biocompatibility of the new bone substitute. Radiographic analysis, micro-CT measurements and histological observation were used to evaluate the bone repair ability in rat tibia bone defects. The XRD and FTIR patterns of Sr-CaS were both very similar to CaS and the product had comparable characteristics similar to α-CaS as demonstrated by TG-DSC. Cytotoxicity of the substitute was class 1 (no cytotoxicity) and hemolysis was 4.3% (no hemolysis). Sub-acute toxicity was not seen after a 14 day evaluation. The substitute was radio-opaque. The empty group exhibited the lowest levels of both bone mineral densities (BMD) and bone volume/total volume (BV/TV) of the defects when compared to all other groups. The two Sr-CaS groups resulted in significantly greater BMDs and BV/TV of the defect compared to the CaS only group. However, there was no significant difference between the 5% and 10% Sr-CaS groups. The Sr-CaS was resorbable with satisfactory biocompatibility. The doped strontium ions enhanced the bone repair performance of CaS in a rat model and the new substitute demonstrated promising results for clinical use.