新型双皮质自攻螺纹交锁螺钉的设计与生物力学研究

目的设计与新型髓内钉相配套的双皮质自攻螺纹交锁螺钉,并对其生物力学性能进行对比研究。方法新型双皮质自攻螺纹交锁螺钉20根,直径4.5 mm,长45 mm,为实验组;市售进口Orthofix髓内钉配套不锈钢单皮质及全螺纹交锁螺钉各20根,规格与实验组相同,为对照组。应用MTS880材料试验机分别对实验组(新型交锁螺钉)及对照组(单皮质螺纹交锁螺钉、全螺纹交锁螺钉)的抗拔出强度及三点弯曲试验进行对比测评。结果新型交锁螺钉的抗拔出性能优于全螺纹交锁螺钉和单皮质螺纹交锁螺钉,单皮质螺纹交锁螺纹钉抗拔出性能最差;新型交锁螺钉的抗弯性能最优,单皮质螺纹交锁螺钉抗弯性能居中,全螺纹交锁螺钉组最差。组间比较均有显著性差异。结论新型交锁螺钉的生物力学性能优良,临床应用的退钉、弯钉、断钉风险低。

Design and biomechanical study on newly-manufactured cortex self-tapping interlocking screw

Objective To compare the biomechanical characteristics by designing newly-manufactured cortex self-tapping interlocking screw matched with interlocking nail.Methods Altogether 20 newly-manufactured cortex self-tapping screws(diameter 4.5mm,length 45mm) were tested as experimental group,20 Orthofix one-side cortex screws and 20 full-length interlocking screws of the same specifications were tested as control group.To compare their anti-pulling and anti-bending capabilities on the MTS880,the experimental group(ten screws) and the control group(ten screws) were tested for different contents.Results The maximal pull-out strength of new-manufactured cortex self-tapping interlocking screw was distinctly higher than that of the full-length cortex interlocking screw,the maximal pull-out strength of one-side cortex interlocking screw was the lowest.Compared with the other screws in the anti-bending capabilities,new-manufactured cortex self-tapping interlocking screw was the best,one-side cortex interlocking screw ranked second and full-length cortex interlocking screw the last.Conclusion The biomechanical characteristics of newly-manufactured cortex self-tapping interlocking screw were better,which can decrease the clinical risk of screw bending,breaking and receding.