摘要目的 建立前后压缩(APC)型骨盆损伤骨-韧带三维有限元模型,并探讨其损伤机制.方法 选择1具56岁男性新鲜尸体骨盆标本,根据APC型骨盆损伤分别建立有限元及实验室力学模型.有限元模型:建立正常骨盆骨-韧带有限元模型,固定右半骨盆,切断并逐渐分离耻骨联合,使耻骨联合分离10、20、30、40、60、80及100 mm.实验力学测试模型:耻骨联合分离28 mm时,骶髂前韧带断裂,代入有限元模型计算出骶髂前韧带的应变值,并应用于模型其他韧带赋值.观察有限元模型中耻骨联合分离距离对应的骶髂关节前方位移,骶髂关节周围韧带的应力、应变及骶棘韧带、骶结节韧带损伤情况.结果 耻骨联合分离28 mm时,骶髂前韧带断裂,此时骶髂关节前方位移为(7.41±1.14) mm,骶髂前韧带的应变值为259.5％,最大等效应力为543.24 MPa.当耻骨联合分离至51 mm时骶棘韧带断裂,此时骶髂关节前方位移为(15.23 ±2.88) mm,最大等效应力为35.00 MPa.当耻骨联合分离至100mm时,骶结节韧带出现紧张但未断裂,此时最大等效应力为16.17 MPa.当骨盆逐渐外旋时,骶髂前韧带先断裂,其次为骶棘韧带断裂,骶结节韧带不一定会断裂.结论 本研究建立的骨盆骨-韧带有限元模型能够有效模拟APC型骨盆损伤机制和量化评估损伤程度,为骨盆骨及韧带的生物力学研究提供了基础.

abstractsObjective To establish a three-dimensional finite element model of pelvic anteroposterior compression (APC) for analysis of mechanisms for related liganentous damages.Methods A finite element model and a laboratory mechanical model of APC were established using the same pelvic specimens.In a finite element model of normal pelvic bones and ligaments,after the right pelvis was fixated the pubic symphysis (PS) was sectioned.Next,a manual external mobile force was gradually applied to the left hemipelvis to make the PS diastasis 10,20,30,40,60,80 and 100 mm apart.The mechanical experiment revealed the anterior sacroiliac ligament (ASIL) was ruptured when the PS diastasis reached 28 mm.After the strain value of ASIL was calculated through the finite element model,it was applied to the other pelvic ligaments.The displacement in front of the sacroiliac joint (SIJ),stress,strain and extent of injury and disruption of sacrotuberous/sacrospinous ligaments (STL/SSL) with a corresponding PS diastasis were observed and recorded.Results ASIL failed at the point when the PS diastasis was 28 mm and the displacement in front of SIJ was 7.41 ± 1.14 mm.The strain and maximum principal stress of ASIL calculated in the finite element model were 259.5％ and 543.24 MPa respectively.The maximum principal stress value of SSL was 35.00 MPa at the point of failure when the PS diastasis and the displacement in front of SIJ were 51 mm and 15.23 ±2.88 mm,respectively.When the PS diastasis and the displacement in front of SIJ were 100 mm and 7.5 mm respectively,the maximum principal stress value of STL was 16.17 MPa but the strained ligament was not ruptured.When the pelvis was rotated externally step by step,the ASIL failure was followed by the rupture of SSL but not necessarily by the STL failure.Conclusion As the finite element pelvic bone-ligament model established in this study can effectively simulate the mechanisms for APC injury,it can be used to evaluate different extents of pelvic ligamentous injury,providing a basis for the biomechanical study of pelvic bones and ligaments.