Biomechanical assessment of freeze-dried allograft cortical bone plate graft in canine bone defect model

Freeze-dried cortical bone can be used as a biological plate, either alone or in combination with other internal fixation devices, to stabilize fractures. In addition to it conferring mechanical stability, freeze-dried cortical bone may enhance fracture-healing and increase the bone stock. This study examined the effect of a freeze-dried allograft cortical bone plate (FACBP) on the biomechanical properties of an implant site in a canine bone defect model. Twelve adult mongrel dogs (around 4.8 kg) were used. A segmental critical-size defect (5 mm in length) at ulna diaphysis was created using an oscillating saw. The experimental animals were divided into two groups: eight dogs treated with an absorbable bone plate (FACBP) fixed by metal bone screws (Group A) and four dogs treated with a commercial stainless steel bone plate and metal bone screws (Group B). Bone healing was assessed by radiography, Dual-energy x-ray absorptiometry and a three-point bending test. The FACBP incorporated in the host bone produced complete remodeling of the cortical bone. There was no significant difference in the bone mineral density and biomechanical tests between the FACBP application site and normal ulna or a stainless steel bone plate of the ulna. These results suggest that FACBP facilitates recovery from a bone fracture by assisting in the induction of new bone formation in a defected fracture.