Rehydration improves the ductility of dry bone allografts

Processing of bone allografts improves infectious safety and allows storing bone substitutes at room temperature. The aim of this study was to compare mechanical properties of the processed Osteopure™ bone with fresh frozen bone. All the samples were pieces from femoral heads retrieved during hip arthroplasty operations. The processing includes chemical decellularization, drying and irradiation with 25 kGy. Three types of samples were tested: 1. fresh frozen thawed wet, 2. dry non-rehydrated graft 3. dry rehydrated graft. In the 3-point bending test Young's modulus and stress at break yielded no significant difference among the 3 different sample groups. Rehydrating of the dry graft showed increased ductility in strain at break test compared with the other 2 groups (p = 0.003). In compression tests dry grafts had significantly higher maximum effective stress and apparent maximum deformation compared with the grafts of other groups (p < 0.05). Processed bone has almost similar mechanical properties compared with fresh frozen bone. However, rehydration of processed dry graft increases its ductility. These grafts may tolerate bending forces better before breakage.