A-P型Gamma钉的生物力学分析

目的　运用生物力学方法对股骨粗隆周围部带锁髓内钉 (即Gamma钉 ,下同 )治疗股骨粗隆周围部骨折所致的并发症及其原因进行研究 ,分析生物力学因素对Gamma钉所致的并发症的影响。方法　将新鲜尸股骨制成E vansⅠ型粗隆间骨折模型 ,用A -P型Gamma钉进行安装固定 ,与不作任何处理的对照组分别在MTS实验机进行抗压和抗扭转实验 ,比较两者的生物力学性能。结果　对照组和A -P型Gamma钉在 30 0N的压力下 ,压缩刚度分别为(15 6 8 0 6± 36 5 81)和 (2 2 4 11± 6 6 45 )N/mm ;扭角为 5度时 ,股骨头的扭转刚度分别为 (1.14± 0 19)和 (0 .114± 0 .0 6 5 )Nm/du。两者差异有显著性。结论　A -P型Gamma钉在抗压和抗扭转强度方面明显低于对照组 ,其潜在的不稳定因素可能是Gamma钉治疗股骨粗隆周围部骨折所致的并发症直接原因。

A biomechanics study of A-P Gamma nail

Objective　To study the complications and cuases of Gamma nail for the treatment of peritrochanteric fracture of femur by biomechanics test.Methods　16 fresh femoral specimens were divided into two groups, each consisting of eight specimens. One group was as control, another was as A-P Gamma nail. Evans typy Ⅰ intertrochanteric fracture were produced and fixed with A-P Gamma nial. In the standing position, press test were carried out on MST tested instrument for to compare the biomechanical property of A-P Gamma nail with the control.Results　 When press was 300N, press strength of control was (1 568.06±365.81) N/mm, was better than that of Gamma nail, which was (224.11±66.45) N/mm; When torsion angle was 5°, torsion strength of control was (1.141±0.191) Nm/du, was better than that of Gamma nail, which was (0.114±0.065) Nm/du. Both press and torsion property were significantly different between two kinds of nail. Conclusion　Control is better than that of A-P Gamma nail in both press and torsion property. It may be the main cause that A-P Gamma nail possesses unstability for the treatment of peritrochanteric fracture of femur.