| ObjectiveFirstly,the study aimed to analyze the widths of the normal sacroiliac joint space in different age groups under computed tomography(CT)scan examination,which provided a reference for the clinical diagnosis of sacroiliac joint subluxation.Secondly,the study aimed to analyze the influences of the manipulation of oblique pulling on the relative motion of the sacroiliac joint and the biomechanical characteristics of the stability of the sacroiliac joint.Lastly,the study aimed to explore the effects of three manipulations,as well as the manipulation of oblique pulling with different force points and different force directions on the stress-strain of the sacroiliac joint.Methods1.A total of 480 cases of normal sacroiliac joint computed tomography images were enrolled.The widths of the sacroiliac joint space in six age groups(10?19 years old,20?29 years old,30?39 years old,40?49 years old,50?59 years old,and above 60 years old)were measured.2.The rotation angles and displacements of sacroiliac joints were compared under the manipulation of oblique pulling F3 and F4 applying on 9 hemi-pelvises and 3 total pelvises.The anterior sacroiliac ligament and symphysis pubis were resected sequentially,and the movement of the sacroiliac joint was measured.3.A femur-pelvis finite element model was established.Four manipulations of oblique pulling were established.F1:the force point was at the anterior inferior iliac spine,and the direction was 30° to the sagittal plane;F2:the force point was at the anterior inferior iliac spine,and the direction was parallel to the sagittal plane;F3:the force point was at the anterior superior iliac spine,and the direction was 30° to the sagittal plane;F4:the force point was on the anterior superior iliac spine,and the direction was parallel to the sagittal plane.The finite element model of pelvis was used to analyze the stresses and displacements of the sacroiliac joint and the strains of surrounding ligaments produced by the four manipulations.4.The femur-pelvis finite element model was used to analyze the stresses and displacements of the sacroiliac joint and the strains of surrounding ligaments caused by manipulation of hip and knee flexion,manipulation of lower limb hyperextension,and manipulation of oblique pulling.Results1.Firstly,the widths of sacroiliac joint space in different age groups were significantly different(P<0.05).With the increase of age,the width of the sacroiliac joint space decreases gradually.Secondly,the width of the sacroiliac joint space in women was greater than that in men,but there was no significant difference.Thirdly,the widths of joint space in the ipsilateral anterior,middle and posterior regions were significantly different(P<0.05),while there was no significant difference between the left and right side of the same region.2.Firstly,the manipulation of oblique pulling could cause slight displacement and rotation of sacroiliac joint on the applied force side,and also produce the movement of sacroiliac joint on the other side and the symphysis pubis,but the range of movement was smaller.Secondly,the manipulation of oblique pulling with the direction parallel to the sagittal plane could lead to greater rotation angle and displacement of sacroiliac joint(P<0.05).Thirdly,under the action of manipulation of oblique pulling,the anterior sacroiliac ligament and pubic symphysis played an important role in maintaining the stability of the sacroiliac joint.Lastly,sacroiliac screw fixation was an effective method to increase the stability of the sacroiliac joint.3.The manipulation of oblique pulling F3 and F4 could produce greater stress on the sacroiliac joint surface.The manipulation of oblique pulling F2 and F4 could cause greater displacements and ligament strains around the sacroiliac joint.4.The three manipulations caused slight displacement of the sacroiliac joint and different degrees of ligament strain around the sacroiliac joint.The manipulation of oblique pulling produced the maximum displacement and the greatest strain of ligaments.ConclusionThe diagnosis of sacroiliac joint subluxation needs to consider the age-related width of joint space.The manipulation of oblique pulling with the direction parallel to the sagittal plane can lead to greater rotation angle and displacement of sacroiliac joint and greater ligament strain.The anterior sacroiliac ligament and pubic symphysis play an important role in maintaining the stability of the sacroiliac joint.Manipulation of hip and knee flexion,manipulation of lower limb hyperextension,and manipulation of oblique pulling can cause slight displacements and different degrees of ligament strains around sacroiliac joint. |
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