Radioprotection and Cross-Linking of Allograft Bone in the Presence of Vitamin E

Abstract

Bone allografts are the preferred method for bone augmentation in about 500,000 orthopaedic surgical procedures in the US. Sterilization by ionizing radiation is the most effective method of minimizing the bioburden of bone allografts; however, radiation causes chain scission of collagen, resulting in the decrease of the mechanical strength of bone. In this study, we impregnated bone allografts with natural free radical scavenger vitamin E as radioprotectant using a novel two step process to protect the collagen architecture against radiation damage. In addition, we investigated combining the radioprotectant with a cross-linking agent, to further minimize collagen degradation. Both of these methods significantly improved the fracture toughness of bone allografts irradiated to 25 kGy and did not affect the osteoblast attachment on radiation sterilized bone. The two-step process also allowed complete impregnation of large bone within 30 hours, supporting the practical use of this technique.