【作者】 邢叔星；

【导师】 王爱民；

【作者基本信息】 第三军医大学 ， 外科学， 2007， 博士

【摘要】 接骨板内固定是治疗四肢骨折的常用方法。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,其目的为进一步减少接骨板与骨面的接触面积,减少其对骨皮质及骨折断端血运的破坏,降低术后并发症的发生。这一理念促进了接骨板研制地极大发展,并相继推出了有限接触动力加压钢板(Limited Contact-Dynamic Compression plate, LC-DCP)、锁定加压接骨板(Locking Compression plate, LCP)、点式接触固定器(Point Contact- Fixator, PC-Fix)及锥状点式接触钢板(Conical Cylinder Point Contact-Fixator, CCPC-Fix)等微创接骨板。但这类接骨板仍存在不同的问题,LC-DCP的有限接触作用被许多学者质疑,其仍依靠与骨面间的摩擦力来达到骨折断端稳定;LCP螺钉孔采用圆锥形螺纹锁定孔和动力加压孔一体化设计,降低了接骨板本身的生物力学性能,同时其与骨面间的接触面积仍然很大;点式接触内固定器(PC-Fix)解决了接骨板与骨面间的接触问题,但PC-Fix螺钉孔仍被设计为圆孔,传统接骨板对骨折断端加压的优点未于保留;CCPC-Fix保留加压作用,其固定力学模式仍是依靠接骨板与骨面间的摩擦力。为了进一步保护骨折端及骨皮质血运,提供骨折愈合的最佳生物学环境。我们研制出了一种新型点接触锁定加压接骨板(Point Contact-Locking Compression plate, PC-LCP),其结合了AO研究进展中骨科接骨板的所有优点,集点接触、锁定及加压功能于一体。点接触设计能最大限度减少接骨板与骨面间接触面积,充分保护骨皮质及骨折断端的血循环,同时保留了加压功能,以适应不同类型骨折,选择性地对骨折断端行加压固定作用,锁定功能改变了接骨板与骨面间的作用模式,转化接骨板与骨面间的摩擦力为锁定螺钉与接骨板间的作用力,使接骨板与螺钉形成一体化结构,可作为一种内在‘外固定架’来应用。本研究以LC-DCP、DCP (Dynamic Compression Plate)为对照,对PC-LCP的生物力学性能、固定不同骨面时的接触特征及其对接骨板板下骨皮质、固定骨折愈合的影响进行研究,为PC-LCP应用于临床提供理论及实验依据。PC-LCP固定骨折生物力学及与骨面接触特性的研究结果:1. PC-LCP在抗弯曲、抗扭转等生物力学特性与DCP、LC-DCP无明显差异;2. PC-LCP与骨面间的接触面积较LC-DCP有明显减少,PC-LCP在不同骨面有稳定的接触特性,而LC-DCP则易受不同骨面特征的影响。研究表明PC-LCP固定骨折的力学稳定性与其它两种接骨板相似,同时PC-LCP能最大限度地减少与骨面间的接触面积,从而达到保护接骨板板下血运的目的。PC-LCP固定对板下骨皮质血流量及板下骨皮质胶原纤维影响的研究结果:1.固定骨折术后1天,PC-LCP对接骨板下血流量及髓腔血流量较DCP及LC-DCP影响要小。2. PC-LCP与DCP固定术后1天板下骨皮质均出现骨缺血区现象,PC-LCP固定组板下缺血区于4周时即恢复,而DCP固定组板下皮质骨于1天、2周、4周持续存在缺血现象,到第8周才渐恢复;PC-LCP固定组板下骨皮质血流量均高于DCP固定组板下血流量,DCP固定组板下血流量至12周才恢复到正常。3. PC-LCP与DCP固定组对接骨板板下胶原均有不同程度的影响,但DCP固定组对板下胶原的影响更加明显,12周时DCP固定组见板下骨胶原排列紊乱明显,可见空泡及断裂出现;PC-LCP固定组板下胶原紊乱及断裂现象没有DCP固定组明显。说明PC-LCP接骨板对骨皮质干扰较小,有效地保护了固定段骨皮质的血运及正常的结构,为促进骨折愈合及减少感染提供一种好的方法。PC-LCP固定骨折骨愈合动物实验研究的结果:1. PC-LCP固定组各期新生血管数量较DCP固定组为多,血管成熟度较高;2.两组接骨板固定荧光标记显示PC-LCP骨愈合能力较DCP固定组稍强,但两者无明显差异;3.骨胶原纤维染色显示两组各期骨胶原形成过程无明显差别,但PC-LCP固定组I型胶原形成较DCP固定组多,成熟度高;4.组织学观察:PC-LCP固定组愈合骨组织骨小梁及新生毛细血管芽形成时间较DCP固定组出现早,成熟度也较DCP固定组高。后期,PC-LCP固定组板层骨及哈佛氏管形成规律,重建明显,DCP固定组新生骨内可见骨吸收腔出现;5. X线显示,术后12周,两种接骨板固定组骨折断端均良好愈合,DCP固定组板下皮质骨见吸收、变薄现象;6.力学性能测试显示PC-LCP固定组骨折愈合质量优于DCP固定组。结果表明:PC-LCP固定骨折骨愈合速度及质量均优于DCP固定组,有利于骨折愈合。综上所述:PC-LCP在不减弱固定力学强度的同时,最大限度地减少了与骨面间的接触面积;PC-LCP能有效地保护板下骨皮质血流及骨胶原的排列,防止接骨板固定后期板下骨质疏松地发生;PC-LCP固定可靠,骨折愈合速度及质量均要优于DCP固定组。PC-LCP接骨板是一种较为完美的内固定材料,为骨折愈合提供了最佳生物学环境,也为临床接骨板应用提供了更多选择机会。更多还原

【Abstract】 Bone plates internal fixation was a common technique for limb fracture at present. In recent years, with the cognition of the bone’s biology character, people have advanced the BO theoretics based on AO. The aims of this change were reduce the breakage of the part of bone blood supply and degrade the complications after bone fracture operation. The change promoted the design of internal fixation evolution greatly. The Low Contact Dynamic compression plate (LC-DCP), Locking Compression plate(LCP), Point Contact Fixator (PC-Fix) and Conical Cylinder Point Contact-Fixator (CCPC-Fix) etc as minimally invasive internal fixation had been designed. However, the limited contact function of LC-DCP has been doubted by many scholar that it still depended on the friction between bone and internal fixation to attaining the stabilization. The integrative design between taper locking bore and dynamic compression bore of LCP weakened the biomechanical of the plate.The question of contact that existed between plate and the bone surface of PC-Fix had been dissolved, but the bore of PC-Fix still been designed to the rotundity which had not reserved compressing function like the traditional internal fixation plate. CCPC-Fix Reserved the function of compression, but it still depended on the friction between the plate and the bone surface to keeping the stabilization of the bone fracture. For protecting the supply of bone fracture and the bone cortex further and providing the best bone healing biological environment, we had designed one new internal fixation plate PC-LCP which integrated the function of locking, point contact and compression. The point contact design could decrease the contact area between the plate and the bone surface that could protect the blood supply of the bone cortex and the bone fracture. The compression function of PC-LCP were a strongpoint of plate which was used to adapting the type of the bone fracture and been used freely when the plate fixed the bone fracture. The locking function changed the force mode between the plate and the bone surface, which changed from the friction force between the plate and the bone surface to the strength between the boil and the plate.In order to provide theoretical and experimental basis for future clinical application, the biomechanical, the biological characteristics, the contact proportion and animal experiments of the PC-LCP were studied with traditional DCP and LC-DCP as a control group.The study of the biomechanical and the contact proportion under the bone surface of the PC-LCP showed: 1. The torsion and bending rigidity biomechanical of PC-LCP compared with that of DCP had not distinct difference; 2. The contact proportion under bone surface of PC-LCP decreased greatly compare with that of LC-DCP. The PC-LCP had the same contact character on different bone surface while the LC-DCP effected easily by the bone surface in contrast. This result revealed that the PC-LCP had the same biomechanical character as the other two traditional bone plate and the PC-LCP could decrease the contact proportion furthest for the aim of protecting the blood supply of bone cortex under the plate.The result of testing the regional microcirculation in cortical bone and observing the change of cortical bone collagen fibers after fixed by PC-LCP and DCP showed: 1.24 hours after operation, the blood supply of cortical bone affected by PC-LCP less than that of DCP group and LC-DCP. 2. Region of the perfusion deficiency was found at 1 day after operation with PC-LCP and DCP fixation. However, it had recovered at 4week with PC-LCP fixation group. DCP application resulted in a continuous perfusion deficiency under the plate at 1day, 2weeks and 4weeks. The perfusion deficiency did not disappear until 8week after operation; The blood supply of bone cortex under the plate PC-LCP was higher than that under the plate DCP at all time. 3. Both the PC-LCP and the DCP had affected the collagen fibers at a certain degree, but the DCP had more affection on the collagen fibers. At 12week, many collagen fibers presented the appearance of corrosion, break and disarrangement under cortical bone fixed by DCP, but the change of collagen fibers in group PC-LCP were not obvious than that in group DCP. PC-LCP illuminated the merit that it disturbed bone cortex less and protected the bone cortex blood supply under the plate effectively which provided a gooe method for promoting the bone healing and decreasing the infecton. Fracture healing experiment was studied in goats. The immunity histochemistry demarcating the growth of new blood vessel, fluorescence marker, Sirius Red stained, histology, X-ray and the biomechanical test of healing bone were used to observed the degree of bone fracture healing. The results showed: 1.The PC-LCP fixed group had more new blood vessel growth than that of DCP fixed group. The newborn blood vessel in group PC-LCP had the more mature character in all times.2. Fluorescence marker showed no distinct difference between group PC-LCP and group DCP in bone healing ability. 3. In group PC-LCP, type I collagen fibers growth more mature than that of group DCP. 4. The histology results showed that in group PC-LCP the rate of fracture healing were better than that of group DCP. 5. X-ray scanning revealed that the fractures healed well in both group PC-LCP and group DCP, but the bone cortex found the phenolmenon of absorb and atenudation. 6. The mechanical test showed that the quality of the fracture healing was superior in group PC-LCP than that of the group DCP.From the analysis above, we can get the conclusions as follow: 1. PC-LCP has the character of the same fixation stability as the traditional bone plate while it has the less contact proportion under the bone surface greatly. 2.PC-LCP can provide the environment of optima bone healing biology by protecting the blood supply and the collagen fibers of cortical bone under the plate, that can prevent the occur of the bone loose later. 2. The PC-LCP can provide better healing rate and healing quality than that of traditional plates. PC-LCP can provide more choice for the clinic application as one perfect internal fixation plate.更多还原