ObjectiveTo evaluate the biomechanical effect of a nickel-titanium (Ni-Ti) three-dimensional memory alloy mesh in treating a canine tibial plateau collapse fracture model and to lay a foundation for further experiments in vivo.MethodsSixteen tibial plateau specimens of 8 adult Beagle dogs were harvested. Twelve specimens were taken to prepare canine tibial plateau collapse fracture models (Schatzker type Ⅲ) and randomly divided into groups A, B, and C, with 4 specimens in each group. Four normal tibia specimens were used as blank control group (group D). In groups A and B, the bone defects were repaired with Ni-Ti three-dimensional shape memory alloy mesh combined with autologous bone and simple autologous bone respectively, and fixed with the lateral plate and screw. In group C, the bone defect was directly fixed with the lateral plate and screw. By using a biomechanical tester, a progressive load (0-1 700 N) was loaded vertically above the femoral condyle. The maximum failure load was recorded and the stiffness was calculated according to the load-displacement curve.ResultsThe maximum failure loads in groups A, B, C, and D were (1 624.72±7.02), (1 506.57±3.37), (1 102.00±1.83), and (1 767.64±24.56) N, respectively; and the stiffnesses were (129.72±20.83), (96.54±27.05), (74.96±17.70), and (169.01±35.62) N/mm, respectively. The maximum failure load and stiffness in group A were significantly higher than those in groups B and C, but which were significantly lower than those in group D (P<0.05).ConclusionNi-Ti three-dimensional memory alloy mesh combined with autologous bone can repair the Schatzker type Ⅲ tibial plateau collapse fracture, which has better biomechanical properties than simple autologous bone grafting.
ObjectiveTo evaluate the effect of nickel-titanium three-dimensional memory alloy mesh combined with autologous bone for living model of canine tibial plateau collapse fracture by biomechanical testing. MethodsSixteen healthy 12-month-old Beagle dogs were randomly divided into 4 group, 4 dogs in each group. The dogs were used to establish the tibial plateau collapse fracture model in groups A, B, and C. Then, the nickel-titanium three-dimensional memory alloy mesh combined with autologous bone (the fibula cortical bone particles), the artificial bone (nano-hydroxyapatite), and autologous fibula cortical bone particles were implanted to repair the bone defects within 4 hours after modeling in groups A, B, and C, respectively; and the plate and screws were fixed outside the bone defects. The dogs were not treated in group D, as normal control. At 5 months after operation, all animals were sacrificed and the tibial specimens were harvested and observed visually. The destructive axial compression experiments were carried out by the biomechanical testing machine. The displacement and the maximum failure load were recorded and the axial stiffness was calculated. ResultsAll animals stayed alive after operation, and all incisions healed. After 1-3 days of operation, the animals could stand and move, and no obvious limb deformity was found. The articular surfaces of the tibial plateau specimens were completely smooth at 5 months after operation. No obvious articular surface collapse was observed. The displacement and maximum failure load of specimens in groups A and D were significantly higher than those in groups B and C (P<0.05). But no significant difference was found between groups A and D and between groups B and C (P>0.05). ConclusionThe nickel-titanium three-dimensional memory alloy mesh combined with autologous bone for subarticular bone defect of tibial plateau in dogs has good biomechanical properties at 5 months after operation, and has better axial stiffness when compared with the artificial bone and autologous bone graft.