Effect of a β-TCP collagen composite bone substitute on healing of drilled bone voids in the distal femoral condyle of rabbits.

In this study, we tested the performance and biocompatibility of a composite of β-tricalcium phosphate (β-TCP) to collagen as a bone void filler (Cerasorb(®) Ortho Foam) in a rabbit distal femoral condyle model. β-TCP is a completely resorbable synthetic calcium phosphate and the addition of a collagen matrix couples the osteoconductive effects of the two components. Furthermore, the malleable properties of the implant material during surgical applications for shape control will be enhanced. A critical size defect of 6 mm in diameter and 10 mm in depth was drilled into each distal femur of the rabbits. One hole was filled with the test substance and the other was left empty for control. After 1, 3, and 6 months the animals were killed and the degree of bone healing analyzed. In total, 18 animals were investigated. When the β-TCP composite was used, histological, histomorphometric, and biomechanical evaluations revealed significantly better bone healing in terms of quantity and quality of the newly formed bone. Moreover, no signs of inflammation were observed in the animals and no allergic or foreign body reaction was noted. This suggests high biocompatibility and osteoconductivity of the investigated material to a bone void in an immune responsive species.