In vitro testing of the osteoinductive potential of different bony allograft preparations

Bony allografts are used frequently in the clinic for bone defect filling, however, less comparative data concerning their osteoinductive potential are available. The purpose of the present study was the comparative analysis of different allograft preparations. From five donors, we investigated fresh-frozen cancellous bone (native), peracetic acid-ethanol sterilized (PES) cancellous bone, cortical bone and demineralised bone matrix (DBM). In addition, two commercially available DBM products from five different donors were analyzed: Allomatrix(A (R)) (Wright Medical Technology Inc.) and DBX putty(A (R)) (Synthes GmbH). For positive control and as a clinically used growth factor, BMP-2 was chosen. To investigate the osteoinductivity C2C12 cells were cultured with the different materials and the effect on cell proliferation and alkaline phosphatase activity were measured. Proliferation was significantly enhanced by the native cancellous bone, Allomatrix, and BMP-2 and decreased by the PES-processed cancellous bone. The osteogenic differentiation was significantly enhanced by BMP-2 and the two commercial DBM products and decreased by PES-sterilized cancellous bone. All tested materials revealed a high donor-dependent variability. This is the first comparative study on the osteoinductivity of bony allografts frequently used in clinic.