实验性股骨颈骨折修复过程的生物力学研究

A Biomechanical Study of Experimental Femoral Neck Fracture during Its Natural Repairing Process

目的 :探索股骨颈骨折引起股骨头坏死塌陷的发病机理。方法 :在犬股骨头颈交界处截断股骨颈 ,术后分5周组 (5条 ) ,2 0周组 (5条 )及各组的对照组 ,对其修复过程进行病理学、计量组织学、四环素标记及生物力学的研究。结果 :(1)病理学检查 :5周组 ,股骨头内骨小梁坏死 ,其框架结构不变 ;2 0周组 ,股骨头关节面塌陷 ,头内纤维组织、软骨痂及骨痂形成。 (2 )计量组织学分析示 2 0周组的股骨头骨小梁体积及软骨下骨厚度较对照组及 5周组低。 (3 )四环素标记示 2 0周组的荧光带比对照组及 5周组宽 ,5周组的最窄。 (4)生物力学测定 :2 0周组的软骨下骨及松质骨的生物力学强度较对照组及 5周组低。结论 :股骨颈骨折可致股骨头坏死 ,后者引起修复及血供重建 ,修复则可导致塌陷 。

Objective:To explore the mechanism of femoral head necrosis and collapse caused by femoral neck fracture.Methods:10 canine femoral necks were broken at the joint of femoral head and neck,then they were devided into three groups:Ⅰ.5th week group(n=5),Ⅱ.20th week group(n=5),Ⅲ.control group of the above two groups.pathological、histomorphometrical、tetracycline labelling and biomechanical examination were performed during the repairing process.Results:1.Pathological examination:In group I,femoral heads were completely necrotic,but there was no change of frame of the trabecular bone.In group Ⅱ,the articular surface of the femoral head was collapsed.There was formation of fibrous tissue,cartilage and bone.2.Histomorphometrical analysis:The TBV and thickness of subchondral bone of the femoral head in group Ⅱ were lower than that of group Ⅰ and Ⅲ.3.tetracycline labelling:The fluorescent band of group Ⅱ was wider than that of group Ⅰ(which was the narrowest of all)and Ⅲ.4.Biomechanical measurement:The biomechanical properties of subchondral bone and trabecular bone in group Ⅱ were lower than that of group Ⅰ and Ⅲ.Conclusion:Femoral neck fracture can cause osteonecrosis which would lead to repair and revascularization,but the repair would lead to collapse.The collapse of femoral head is colsely related to the biomechanical properties.