Absorbable fixation materials such as ceramics decalcified cortical bone and several synthetic absorbable polymers have been used in orthopedic surgery. But these absorbable materials have some disadvantage such as early resorption, low strength and limited fixation ability.
The purpose of this study was to investigate the effectiveness of freeze-drying allograft cortical bone (FACB) as an internal fixator in canine fracture model.
Fracture models were made by creating segmental defect (5 mm in length) at ulna diaphysis in 18 dogs. Twelve dogs were applied FACB and metal screws (group A), and 6 dogs were treated with commercial metal bone plate and screws (group B). New bone formation, union of fracture site, and resorption of bone plate were evaluated by radiography in every 2~4 weeks intervals for 135 weeks.
The fracture healing was successful in all dogs of group A and B. The bony callus formation was observed from 5.7 weeks and 2.7 weeks after surgery in group A and B, respectively. A complete union was achieved by 13 weeks and 6.7 weeks in group A and B, respectively. The time of resorption process was started from 7 weeks and continued to 48 weeks in group A.
The FACB could be used efficiently and safely in orthopedic practice as an internal fixation material. Since the FACB was absorbable firmly, no risk of additional surgery is required to eliminate the fixation devise as in conventional method. Furthermore, the slow resorption of the FACB was suitable to support and heal the fractured bone.