A finite element analysis of sacroiliac joint displacements and ligament strains in response to three manipulations

Zhun Xu,Kai Wu,Ziyu Feng,Dan Li,Liqing Liao,Yikai Li,Shaoqun Zhang

doi:10.1186/s12891-020-03735-y

Abstract

BackgroundClinical studies have found that manipulations have a good clinical effect on sacroiliac joint (SIJ) pain without specific causes. However, the specific mechanisms underlying the effect of manipulations are still unclear. The purpose of this study was to investigate the effects of three common manipulations on the stresses and displacements of the normal SIJ and the strains of the surrounding ligaments.MethodsA three-dimensional finite element model of the pelvis-femur was developed. The manipulations of hip and knee flexion (MHKF), oblique pulling (MOP), and lower limb hyperextension (MLLH) were simulated. The stresses and displacements of the SIJ and the strains of the surrounding ligaments were analyzed during the three manipulations.ResultsMOP produced the highest stress on the left SIJ, at 6.6 MPa, while MHKF produced the lowest stress on the right SIJ, at 1.5 MPa. The displacements of the SIJ were all less than 1 mm during the three manipulations. The three manipulations caused different degrees of ligament strain around the SIJ, and MOP produced the greatest straining of the ligaments.ConclusionThe three manipulations all produced small displacements of the SIJ and different degrees of ligament strains, which might be the mechanism through which they relieve SIJ pain. MOP produced the largest displacement and the greatest ligament strains.

Highlights

Clinical studies have found that manipulations have a good clinical effect on sacroiliac joint (SIJ) pain without specific causes
The differences in maximum stress and maximum displacement between mesh 3 and mesh 4 in all three manipulations were less than 5%, which was concluded as reasonably close ranges
We found that higher stress was observed on the left SIJ, which may be related to the manipulative force applied to the left SIJ

Summary

Introduction

Clinical studies have found that manipulations have a good clinical effect on sacroiliac joint (SIJ) pain without specific causes. The mechanism may include the following processes: Pathogenic factors acting on the auricular surface of the sacrum and ilium may cause injury to the ligaments or muscles around the SIJ, which will result in slight movement of the SIJ, making the joints difficult to reset. The mechanical environment of the joints may be imbalanced, and the soft tissues will be damaged This condition is clinically referred to as SIJ subluxation [4]. Pathological bone destruction and traumatic fracture and dislocation require surgery [15,16,17,18], while SIJ pain without a specific cause is usually treated with manipulations [19, 20]

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