| Part1Objective:To establish a firearm injury in New Zealand white rabbits tibia bone defect animal model.Methods:32New Zealand white rabbits using the multifunctional biological impactor two projection device system, and divided into four groups according to the quality of steel ball and high-pressure nitrogen gas pressure control launch speed. According to the projectile velocity calculation the energy of injury, observe local injury, penetrating wound measuring the average area of entrances, cavity volume and radiographic evaluation of bone defect length. Statistical analysis of each group and the coefficient of variation injury situation (CV) model to evaluate the stability of the injury, and explore manufacturing rabbit bone defect model firearm injury optimal conditions.Results:All animals hind limb were penetrating wound, open comminuted fracture of tibia and fibula. Group D injury maximum energy, B, C group followed, a group make minimum energy injury. B and C group wound track entrance and exit wound tract area and volume stability better than other local injury indicators A, D groups. The result stability of group B is better than the other3groups by imaging tests showed the length of the bone defect and has a significant difference (P<0.05). Eventually established with condition of group B (4mm0.24g ball, nitrogen Pressure1.4MPa, average speed ball Projectile776.9±19.7m/s), resulting in New Zee land white rabbits firearm injury tibia bone defects1.02±0.16cm. The animals will have long-term survival after debridement and anti-infective therapy.Conclusion:This method has simple operation, animals have stable condition and the repeatability of the experiment was satisfactory. So we can establish an effective rabbit tibia bone defect animal model of firearm injuries.Part2Objective:To investigate the ability of porous tantalum material to repair segmental bone defect of firearm injury.Method:Relying multifunctional biological impact machine projection system to projected high-speed steel ball for established rabbit tibia bone defect model of firearm injuries.36New Zealand white rabbits were divided into firearm injury tantalum implants group, non-firearm injuries and tantalum implant group and the firearm injury control group. According to New Zealand white rabbits tibia size, porous tantalum rod processed into a hollow cylindrical porous tantalum block and use Kirschner wire intramedullary fixed. In after4weeks,8weeks,16weeks, respectively contrast the conditions of firearm injury and non firearm injury’s difference between bone ingrowth of porous tantalum material surrounding and the gap of material by gross observation, X-ray and histologicalevaluation.Result: Specimen drawn and radiographic observation: fibrous tissue covering thematerial surface after4weeks and8weeks appeared periosteal reaction, new bone callusextended materials. After16weeks, firearm injury group’s callus completely wrappedporous tantalum material, Lane-Sandhu X ray scores highest group is firearm injury oftantalum implant group and blank control group was the lowest. Histological evaluationfound that the group due to firearm injury around the bone fragments large contact areawithin the red dye porous tantalum material new bone and osteoblasts proportion offirearm injuries than non-group.16-Week exhibition area of bone tissue within thematerial of bone defects area percentage: Non-firearm injury group (18.71±3.66)%;firearm injury group (10.38±1.90)%. Difference was statistically significant (P <0.05).Conclusion: In the condition of firearm injury, porous tantalum material still has agood bone ingrowth characteristic for the treatment of bone defects in the future. Itprovides a theoretical basis for the useful of porous tantalum material repair large bonedefects. |
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