有限元方法在军事训练伤后骶髂关节失稳物理查体中应用研究

Applicability of finite element method in physical analysis of sacroiliac joint instability after military training injury

目的建立骶髂关节的三维有限元模型,模拟6个经典物理查体试验的生物力学条件以明确具体韧带产生的疼痛来源,提高该病诊断治疗效率。方法(1)应用3D-DOCTOR和Rapidform两种软件重建骶髂关节3D CAD模型;(2)在CAD模型基础上,应用Femap软件建立骶髂关节的FE模型和三维张力桁架单元;(3)应用Abaqus Standard 6.10版软件研究骶髂关节上的接触压力和每个韧带的应变,对骶髂关节三维模型进行有限元分析。结果(1)髋关节骨盆皮质骨的最大主应变主要分布在髋臼上方至髋臼后部,并延伸至坐骨大切迹、髂嵴及髋臼后部;(2)最大压力在骨盆挤压试验中为左侧10.2 MPa,在大腿推力试验中为14.1 MPa,在Patricks试验中为23.6 MPa,在Gaenslens试验中为27.9 MPa,而骶尖压力试验中最大压力为3.1 MPa;(3)挤压试验韧带最大应变发生在左侧骨间骶髂韧带(ISL),应变值为9.3%;分离试验韧带最大应变发生在左右侧ISL,应变值为4.4%;骶尖压力试验韧带最大应变发生在左右侧ISL,应变值为6.6%;大腿推力试验韧带最大应变发生在左侧骶髂后短韧带(SPSL),应变值为16.3%;Patricks试验韧带最大应变发生在双侧ISL,应变值左侧为13.8%,右侧为14.9%;Gaenslens试验韧带最大应变发生在右侧SPSL,应变值为22.2%。结论该研究通过有限元分析在物理查体中对骶髂关节及单个韧带接触压力进行了定量预测。每次测试中所涉及的接触压力和韧带的组合均有较大差异。这些差异可能有助于了解骶髂关节疼痛的具体来源,加快诊断和治疗的进程,可促进骶髂关节失稳伤员的快速康复。

Objective To establish a three-dimensional finite element model of the sacroiliac joint and simulate the biomechanical conditions of six classical physical examinations to identify the source of pain produced by specific ligaments and improve the efficiency of diagnosis and treatment of the disease.Methods(1)A 3 DCAD model of the sacroiliac joint was reconstructed by 3 D DOCTOR and Rapidform software.(2)AN FE model and three-dimensional tension truss element of the sacroiliac joint were established by Femap software on the basis of the CAD model.(3)The contact pressure on the sacroiliac joint and the strain of each ligament were studied with Abaqus Standard software(version 6.10),and finite element analysis was performed on the three-dimensional model of the sacroiliac joint.Results(1)The maximum principal strain of the pelvic cortical bone of hip joints was mainly distributed from above the acetabulum to the posterior acetabulum,and extended to the large ischial notch,iliac crest and posterior acetabulum.(2)The maximum pressure occurred on the left side in the pelvic crush test with a value of 10.2 MPa,14.1 MPa in the thigh thrust test,23.6 MPa in the Patricks test,27.9 MPa in the Gaenslens test and 3.1 MPa in the sacral apex pressure test.(3)The maximum strain of the extrusion test ligament occurred in the left interosseous sacroiliac ligament(ISL),with a strain of 9.3%.The maximum strain of the separation test ligament occurred in the left and right ISL,with a strain of 4.4%.The maximum strain of the sacral tip pressure test ligament occurred in the left and right ISL,with a strain of 6.6%.The maximum strain of thigh thrust test ligament occurred in the left posterior sacroiliac short ligament(SPSL),with a strain of 16.3%.The maximum strain of Patricks test ligament occurred in the ISL,and the strain values were 13.8%on the left side and 14.9%on the right side.The maximum strain of the Gaenslens test ligament occurred in the right SPSL,with a strain of 22.2%.Conclusion In this study,finite element analysis has been used to quantitatively predict the contact pressure of the sacroiliac joint and individual ligaments in physical examinations.The combinations of contact pressures and ligaments involved in each test are quite different.These differences may shed light on the specific source of sacroiliac joint pain and accelerate the process of diagnosis and treatment,which can promote the rapid recovery of patients with sacroiliac joint instability.