Biomechanical properties of canine corticocancellous bone frozen in normal saline solution

Eleven pairs of canine metacarpal bones, 10 pairs of metatarsal bones, and 7 pairs of ribs were harvested cleanly and prepared for banking at -20 C for 1 year. One bone of each pair was randomly assigned to 1 type of storage: plastic pack vs immersion in a normal solution of sodium chloride. The contralateral bone was assigned to the opposite treatment. Six pairs of metacarpal bones and 5 pairs of metatarsal bones were tested in torsion to failure. No significant difference was found within pairs. All ribs, 5 pairs of metacarpal bones, and 5 pairs of metatarsal bones were loaded in 4-point bending to failure. The energy absorbed at failure and the ultimate displacement of ribs and metacarpal and metatarsal bones were increased by 25 to 30% and 18 to 24%, respectively, when the bones were frozen in isotonic saline solution. Corticocancellous grafts frozen in normal saline solution are biomechanically less fragile and brittle than grafts stored in plastic without saline solution.