Purpose: Current research is focusing on the imitation of the optimal osteoconductive and osteoinductive properties of bone graft. We used in this study a β-trical-cium-phosphate scaffold impregnated with an osteogenetic transglutaminase (plasmatransglutaminase, FXIII, (Fibrogammin®)).

Methods: Release study: 27 & #946;-TCP discs (8x10mm) were impregnated with 10, 40 and 100 IU of FXIII. The release was measured with ELISA.|Animal study: A bilateral tibial metaphyseal defect (8.5 x 20 mm) was performed in eighteen adult sheep. The defects were filled with a & #946;-TCP cylinder (chronOS®, Synthes) in 16 sheep and left unfilled in 2 sheep (control group). The cylinders were impregnated with autologous venous blood, autologous bone marrow aspirate from the sternum and 125 IU FXIII in 4 sheep each or left unfilled and a daily dose of 1250 IU FXIII administered iv. over 14 days. After 6 and 12 weeks QCT, histology and histological analysis was performed.

Results: Release study: We found a linear release of FXIII with a plateau after 48 h. Until then on average 18% of the total dose was release from the scaffold. Animal study: The QCT analysis found unspecific changes in all group without any clear results regarding remodeling of the scaffold. The histological analysis showed the best bone ingrowth after 6 weeks in the bone marrow group and after 12 weeks in the local F XIII with on average 10% more bone ingrowth than in any other group. The best remodeling of the inner area in the scaffold was also seen in the local F XIII group.

Conclusions: FXIII is only partially released from a β-TCP scaffold. At least 80% of the dose remains in the scaffold after 48h. F XIII has a good osteogenetic property which is at least as good as bone marrow and better than venous blood; however a local application of F XIII is preferable to iv. administration. It stimulates osteoblast migration and proliferation in a β-TCP scaffold and causes a remodelling on the inside of the scaffold.

Funding : Commerical funding

Funding Parties : Grant by the AO Research Institute Davos, Switzerland and Synthes, Oberador, Switzerland