单侧骨皮质缺损对长管状骨生物力学的影响

目的探讨长管状骨骨干不同大小的单侧骨皮质缺损对长管状骨生物力学性质的影响。方法取76根三黄鸡胫骨,随机分7组(1.5mm组n=11,2.0mm组n=9,2.5mm组n=13,3.0mm组n=12,3.5mm组n=8,4.5mm组n=11,皮质完整组即正常对照组n=12),于后侧骨皮质造成直径分别为1.5～4.5mm的环形骨缺损,进行三点弯曲单一实验,皮质完整组作为正常组对照。结果缺损直径为1.5mm及2.0mm组鸡胫骨达到结构破坏时的最大载荷与正常组差异无统计学意义(P=0.824,0.865),2.5mm、3.0mm、3.5mm组的最大载荷较正常组降低14%左右,差异有统计学意义(P=0.015,0.010,0.021);4.5mm组较正常组降低23%左右,差异有统计学意义(P=0.001)。结论单侧皮质缺损直径在长管状骨外径的(22.6±1.4)%以内时,不影响其抗弯曲性能;当其超过长管状骨外径的(29.4±2.1)%时,将降低长管状骨的抗弯曲性能,但降低的幅度跟缺损大小并不完全呈正比。

An experimental study on biomechanical effects due to unilateral cortical bone defect in long tubular bone

OBJECTIVE: To investigate the biomechanics effect due to unilateral cortical bone defect of different size in long tubular bone. METHODS: Seventy-six pieces of Sanhuang cock tibial were randomly divided into 7 groups. The unilateral diaphyses cortical were drilled holes of different size, include 1.5, 2.0, 2.5, 3.0, 3.5, and 4.5 mm, performed three-points bend single experiment. The intact bone cortical group was control group. RESULTS: When there were bone structure destructions, the maximum of the bend load between 3 groups which bone defect diameter were 1.5 mm, 2.0 mm, and control was not significant difference (P = 0.824, 0.865), but the maximum of the bend load between 3 groups which bone defect diameter were 2.5, 3.0, and 3.5 mm decreasing about 14 percent of the control group (P = 0.015, 0.010, 0.021). and the maximum of the bend load which bone defect diameter were 4.5 mm decrease about 23 percent of the control group (P = 0.001). CONCLUSIONS: If the diameter of bone cortical defect is within 22.63 +/- 1.39 percent of bone cortical outer diameter, there was no reduction of the bend load. If the diameter of bone cortical defect is beyond 29.36 +/- 2.07 percent of bone cortical outer diameter, it decreases the maximum bend load of the long tubular bone, but the reduced range is not complete with direct ratio to the bone defect size.