锁定加压钢板内固定对犬双侧胫骨中段骨折愈合的影响

Effect of the locking compression plate by internal fixation on fracture healing of dog bilateral middle tibia

背景：近年来随着人们对骨折愈合生物学特征的重视,在AO基础提出了BO理念,这一理念促进了接骨板研制的极大发展。目的：观察锁定加压钢板内固定对犬双侧胫骨中段骨折愈合的影响。设计、时间及地点：对比观察,于2006-06/2007-10在南方医科大学创伤骨科组织工程实验室完成。材料：24只健康成年家犬,体质量14.5～21.2kg,雌雄不拘,用于制备双侧胫骨中段横形骨折模型。锁定加压钢板,316L不锈钢制作,由天津正天医疗器械有限公司提供;同等型号AO传统钢板,由马特仕（上海）医疗器械贸易有限公司提供。方法：将实验动物小腿胫骨右侧用锁定加压钢板内固定作为实验组,左侧用同等型号的AO传统钢板内固定作对照。主要观察指标：术后2,4,6周获取骨标本分别行X射线、光镜、微血管造影观察和钢板下皮质骨微血管面积分数分析。结果：①X射线观察：两种接骨板固定组骨折断端均良好愈合,实验组有较多的骨痂,对照组板下皮质骨见吸收、变薄现象。②光镜观察：对照组钢板下较早出现明显的骨吸收腔,大多骨细胞结构破坏;实验组钢板下未出现骨吸收腔,大多骨细胞结构完整。③微血管造影观察：术后2周,对照组钢板下皮质骨出现大面积缺血区,并持续到术后6周;术后2周,实验组钢板下出现较小范围的缺血区,但微血管走行及分布紊乱,到术后6周,缺血区基本消失,微血管走行基本恢复正常。④钢板下皮质骨内微血管面积分数分析：术后2,4,6周,实验组分别为对照组的1.78,2.26,2.69倍,差异具有显著性意义（P〈0.05～0.01）。结论：锁定加压钢板能保护骨折早期骨膜血供,骨折愈合后期能减轻皮质骨内静脉回流阻力,有利于离心性血流的恢复,促进骨折愈合。

BACKGROUND： BO theory is introduced based on AO theory with the more attention to biological performance of fracture healing, which seriously promote the rapid development of bone plate. OBJECTIVE： To study the effect of the locking compression plate （LCP） by internal fixation on fracture healing of dog bilateral middle tibia. DESIGN, TIME AND SETTING： A contrast study was performed at the Traumatic Orthopaedics Tissue Engineering Laboratory of Southern Medical University from June 2006 to October 2007. MATERIALS： A total of 24 healthy adult dogs weighing 14.5-21.2 kg and of either gender were used to prepare bilateral middle tibia fracture models. LCP was made of 316L stainless steel and provided by Zhengtian Medical Apparatus Co., Ltd., Tianjin. Conventional AO stainless steel plate was provided by Mateshi （Shanghai） Medical Apparatus Trading Co., Ltd. METHODS： Right tibia was treated with internal fixation of LCP as the experimental group, and left tibia was treated with conventional AO plate as the control group. MAIN OUTCOME MEASURES： Samples were performed with X-ray examination, optic microscope, and microangiography, while microvessel image surface fraction was analyzed at 2, 4, and 6 weeks after operation. RESULTS： （1） X-ray examination： The fractures healed well in both the experimental group and the control group, but a lot of bone calluses were found in the experimental group; while absorption and attenuation were found in bone cortex in the control group. （2） Optic microscope： Bone absorption cavity was found in the control group, and structure of osteocytes was destroyed mostly. Bone absorption cavity was not found in the experimental group, and structure of plentiful osteocytes was intact. （3） Microangiography： A large area of ischemic region was found in bone cortex in the control group 2 weeks postoperatively and still observed 6 weeks postoperatively. A small area of ischemic region was found in the experimental group 2 weeks postoperatively; however, courser and distribution of microvessels were disorder. Six weeks later, the ischemic region disappeared generally, and courser of microvessels generally reached normal level. （4） Microvascular image surface fraction： At 2, 4, and 6 weeks postoperatively, the surface fraction in the experimental group was 1.78, 2.26, and 2.69 times as control group, and there was significant difference between them （P 〈 0.05-0.01）. CONCLUSION： The LCP can preserve the cortical bone blood supplies in early phase of bone fracture; while, the LCP can relieve venous return resistance and facilitate centrifugation blood flow recovery, and improve fracture healing in late phase of bone fracture.