Finite Element Analysis Of Sacroiliac Joint In Parturient

OBJECTIVE: Using finite element technology to investigate the stress changes of female sacroiliac joint after vaginal delivery,and to explore the mechanism and pathogenesis of sacroiliac joint pain in pluripara,so as to provide guidance for clinical practice.METHODS: A healthy pluripara for sacroiliac joint CT scan.Using Mimics,Geomagic Studio,Pro/e,Ansys software to establish three-dimensional finite element model.After verifying the authenticity and working conditions seting.A vertical force(600N)was loaded on the upper surface of the sacrum,stress,strain and displacement of the sacroiliac joint were calculated,then compared with the experimental data in literature.RESULTS: An effective sacroiliac joint model had been established successfully.The data of stress,strain and displacement change in 14 points were obtained.Compared with literature data,stress and displacement peak was decreased in standing position.Also the strain changes slightly.In sitting position,the maximum stress in the middle part of sacroiliac joint was increased,and the stress in the upper part was significantly reduced.In the displacement results,the maximum displacement of the upper part increases and the middle part decreases.The result of strain value is consistent with that of standing position.CONCLUSION:1.The three-dimensional finite element model can analyze the mechanical changes of sacroiliac joint in different postures for parturient women.2.The sacroiliac joint was the main load-bearing structure of the pelvis under both standing and sitting conditions.3.In standing position,joint instability was compensated by muscles and ligaments,and the overall stability is maintained,while in sitting position,the instabilty can not compensated by the muscles and ligaments alone,needing interarticular bone to bone chimera to enhance.4.Postpartum sacroiliac joint and surrounding ligament did not fully recover the original mechanical properties,through further development,it may be one of the pathogenesis of sacroiliac joint dislocation,or even joint degeneration.5.We need to pay attention to the early rehabilitation intervention,adjust the endocrine level,develop the right posture habit after maternal production.