In a bone alloimplant in muscle, the structure of the organic matrix evocates or promotes a morphogenetic response from migratory mesenchymal cells. Radiation sterilization destroys the morphogenetic property at a much lower dose of cobalt 60 in undemineralized than in the demineralized bone. Damage to the organic matrix is heightened by excitation transfer from the radiated bone mineral to the matrix proteins. The mineral having an apatite structure also has a relatively high ionization potential and generates deleterious free radicals, which convert the matrix collagen to gelatin. Radiolysis prevents neither the undesirably delayed hypersensitivity response nor the degradation of the bone morphogenetic property by endogenous protease. These observations account for the failure of freeze-dried and radiation-sterilized bone to promote repair of large bone defects in adult patients.
Urist MR, Hernandez A. Excitation Transfer in BoneDeleterious Effects of Cobalt 60 Radiation-Sterilization of Bank Bone. Arch Surg. 1974;109(4):486-493. doi:10.1001/archsurg.1974.01360040012004