Tepic S, Remiger A R, Morikawa K, Predieri M, Perren S M
Research Institute, AO/ASIF Foundation, Davos, Switzerland.
J Orthop Trauma. 1997 Jan;11(1):14-23. doi: 10.1097/00005131-199701000-00005.
Comparison of fracture healing with two different implants: a conventional Dynamic Compression Plate (DCP) and a new internal Point Contact Fixator (PC-Fix).
Randomized, prospective study in experimental animals. Observation times: 12, 24, 48 and 96 weeks, with six sheep per group.
Following surgery, animals were kept with unrestricted weight-bearing in individual stalls for 12 weeks, thereafter in groups.
56 adult Swiss mountain sheep.
A standardized oblique fracture of the sheep tibia was reduced and compressed by a lag screw and "neutralized" with one of the implants.
Standard radiographs were used for callus size measurements. After sacrifice the implant was removed and both the treated bone and the contralateral bone were tested for static strength in bending with the plate side under tension. Broken bones were processed for histological evaluation.
In the DCP group all six bones failed through the original fracture at 12 weeks. At 24 and 48 weeks two out of six, at 96 weeks one out of six bones failed through the original fracture, others through one of the screw holes. In the PC-Fix group there were no failures through the original fracture with a single exception at 96 weeks. The strength values in the PC-Fix groups of 12 and 96 weeks were significantly higher then in the corresponding DCP groups.
Healing of simple diaphysial fractures treated by PC-Fix was superior to that achieved by conventional plating. The histological evaluation suggested that the observed differences can be accounted for by the absence of implant-related cortical necrosis and by the circumferentially uninterrupted (if smaller) callus in the PC-Fix group.
比较两种不同植入物（传统动力加压钢板（DCP）和新型内固定点接触固定器（PC-Fix））对骨折愈合的影响。
在实验动物中进行的随机前瞻性研究。观察时间：12周、24周、48周和96周，每组6只绵羊。
手术后，动物在单独的畜栏中自由负重饲养12周，之后分组饲养。
56只成年瑞士山地绵羊。
对绵羊胫骨进行标准化斜形骨折，用拉力螺钉进行复位和加压，并用其中一种植入物进行“中和”。
使用标准X线片测量骨痂大小。处死动物后取出植入物，对治疗侧骨和对侧骨进行弯曲静态强度测试，钢板侧置于张力下。对骨折的骨头进行组织学评估。
在DCP组中，所有6只羊的骨头在12周时均在原骨折处断裂。在24周和48周时，6只中有2只，在96周时，6只中有1只在原骨折处断裂，其他则通过其中一个螺钉孔断裂。在PC-Fix组中，除96周时有1例例外，没有在原骨折处发生断裂。PC-Fix组12周和96周时的强度值显著高于相应的DCP组。
PC-Fix治疗的简单骨干骨折的愈合优于传统钢板固定。组织学评估表明，观察到的差异可归因于PC-Fix组不存在与植入物相关的皮质坏死以及骨痂在圆周上未中断（尽管较小）。
