应用要点：本实验提出了骨缺损研究应该注意的几个问题：①缺损的位置。②缺损的宽度和长度。③生物力学指标的选择。实验结果提示：①矩形骨缺损模型更有利于探讨骨缺损对骨干生物力学的影响，并发现更小的骨缺损会导致骨干的力学性能下降。②骨缺损的位置对力学性能的影响可能不同。

同行评价：课题为国家“九七三”计划项目的子课题。实验在以往的基础上作了一些调整和探索，定量分析了矩形皮质缺损的长度和宽度对羊骨干抗弯生物力学的影响，设计合理，有一定创新，对临床上采取合理的干预措施有一定的指导意义。为初步判定缺损风险提供了理论依据。

术语解析：三点弯曲试验：将标本放在有一定距离的两个支撑点上，在两个支撑点中点上方向标本施加向下的载荷，标本的三个接触点形成相等的两个力矩时即发生三点弯曲，标本将于中点处发生断裂。三点弯曲试验并不是测量骨干抗弯曲性能的最薄弱区，而是在标本上的感兴趣区。

摘要
目的:皮质缺损的宽度和长度对骨干的生物力学强度均有影响，既往对缺损宽度的研究较多，对缺损长度的研究很少。实验拟验证皮质缺损长度对骨干生物力学性能的影响。
方法：实验于2007-10/12在北京大学人民医院创伤骨科实验室完成。⑴实验材料：新鲜成年山羊股骨标本54个，纳入标准：①外观没有破损。②骨干最窄处冠状面直径范围在14~17 mm 之间，矢状面直径在14~17 mm 之间。骨干长度> 120 mm。⑵实验方法：在骨干张力侧制作矩形单侧骨皮质缺损，缺损的宽度分别为骨干冠状面直径的10%和20%，长度分别为缺损宽度的2，3，4，5倍。没有皮质缺损的正常骨作为对照。对标本进行三点弯曲测试，力学指标包括最大负荷、最大功耗和断裂负荷。
结果：当矩形缺损的宽度为横径的20%，缺损的长度达到宽度的4倍和5倍时，骨干的抗弯曲负荷较对照组降低，P值分别为0.007和0.014；当矩形的宽度为横径的10%，长度达到宽度的5倍时，骨干的抗弯曲负荷与对照组比较，差异显著（P=0.008）。两组标本达到破坏时的最大功耗均较正常对照降低（P < 0.05，P < 0.01）。
结论：①骨干抗弯曲能力随缺损长度的增加降低。②从缺损的宽度和长度两个方面分析缺损对骨干的力学影响更为准确。
关键词：皮质缺损，矩形；长管状骨；生物力学；骨组织构建

陈建海，姜保国，张殿英，付中国. 沿骨干轴线不同长度皮质骨缺损对骨干生物力学性能的影响[J].中国组织工程研究与临床康复，2008，12(11):2011-2014 [www.zglckf.com/zglckf/ejournal/upfiles/08-11/11k-2011(ps).pdf]

Influence of cortical bone defects of different lengths on biomechanics of long tubular bone

Abstract

AIM：Cortical defect width and length can influence biomechanics of tubular bone. Many studies have been conducted to focus defect width, but there are little reports about defect length. This study explored the effect of cortical bone defect length on biomechanics of long tubular bone.
METHODS: The experiment was performed at Department of Orthopaedics and Traumatology, Peking University People's Hospital from October to December 2007. ①Fifty-four fresh femur samples of adult goat, with no damage in appearance, coronal plane diameter of 14-17 mm and sagittal plane diameter of 14-17 mm, and bone length > 120 mm, were employed in this study. ②Unilateral square cortical defects were created by drills on tension site of long tubular bone; the defect width was 20% and 10% of the coronal diameter, and the length of defect was determined as 2, 3, 4, 5 folds of each width. Normal goat femurs served as controls. Three point bending test was performed for each sample to determine the biomechanical parameters such as maximum load, maximum power and breakage load.
RESULTS: The maximum load and breakage load were significantly lower than control group when the defect width was 20% of diameter, and length was 5 fold and 4 fold of width (P=0.007 and 0.014). When the defect width was 10% of diameter, and length was 5 fold of width, the maximum load and breakage load were statistically significant compared with control group (P=0.008). The maximum power consumption of two sample groups was significantly decreased compared with control group (P < 0.05, P < 0.01).
CONCLUSION: ①Anti-bending ability of long tubular bone is decreased when cortical length is increased; ②Considering the influence of both cortical defect width and length would accurately explore the biomechanics of tubular bone with irregular defect.

Chen JH, Jiang BG, Zhang DY, Fu ZG. Influence of cortical bone defects of different lengths on biomechanics of long tubular bone.Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu 2008;12(11):2011-2014(China)
[www.zglckf.com/zglckf/ejournal/upfiles/08-11/11k-2011(ps).pdf]