Study On The Accuracy And Clinical Applications Of Radiological Evaluating Children's Humeral Lateral Condyle Fracture

Objects:The purposes of this study were 1)Providing relevant theoretical basis and corresponding strategies for the systematic prevention of children HLCF occurrence,through the retrospective survey and analysis of the constituent ratios of the fracture type,age of onset,gender,and pathogenicity of childhood HLCF in Tianjin;2)Based on human corpse HLCF model,the accuracy of X-ray and MRI in evaluating the degree of fracture displacement and the discipline of fracture displacement are explored from the aspect of biomechanics,which can provide a reliable theoretical basis for the clinical study of imaging evaluation of the accuracy of HLCF in children;3)The differences of X-ray and MRI were compared in determining the fracture stability of HLCF and in evaluating the degree of fracture displacement,and explore the clinical application value of MRI in the diagnosis of children HLCF without significant displacement.Methods:1)1736 children with elbow fractures were admitted to Tianjin Hospital from August 2016 to December 2017.A descriptive study was conducted on the epidemiological data of this group.The characteristics and development trends of HLCF patient's fracture pattern,age of onset,gender,causes of injury and so on were summarized;2)Rotating the forearm at 0°,45°,90°and 135°in turn under the flexion and extension of elbow.Then Capture Motion System(CMS),elbow X-ray and MRI were used to measure the displacement distance of lateral/posterior fractures of HLCF fracture models.The CMS measurements were true fracture gap distances.The statistical differences among the measurements of CMS,X-ray and MRI were compared.The paired sample t-test was utilized to identify whether the extension/flexion of the elbow had an effect on fracture displacement;3)X-ray and MRI were performed in 60 children suspected with HLCF clinically.It was used as fracture criteria that fracture lines were observed during surgery or callus was found in follow-up.The differences were compared in diagnosing of fractures and trochlear cartilage chain integrity between X-ray and MRI.The differences were compared in evaluating the extent of fracture displacement between X-ray and MRI;and explored the best MRI examination sequence for children with HLCF;35 HLCF children without significant displacement on X-ray were assessed the stability of the fracture and the degree of fracture displacement by MRI,then according to the results of MRI,the appropriate treatment measures were taken in order to explore the diagnostic value and clinical guidance of MRI for HLCF.Results:1)HLCF accounted for 17.22%(299/1736 cases)of pediatric elbow fractures in Tianjin.The high incidence age of HLCF is 3~6 years old,and the trend of fracture incidence with age showed a unimodal distribution.There were more boys than girls in all age groups.The incidence of fracture in the right elbow is higher than that in the left elbow.The main factors leading to HLCF between 0 and 6 years include crash and fall from height,though the risk of fracture caused by sports injury after school increases significantly.2)The lateral and posterior fracture displacement of HLCF model measured respectively by CMS,X-ray and MRI,at 0°,45°,90°,and 135°rotated along the central axis of the forearm,regardless of whether the elbow is flexed or extended.The gap distance showed statistical differences among the three groups after multi-sample analysis of variance(p<0.05),and the measurements of CMS and MRI were larger than the measurement of X-ray(p<0.05).There was no statistically significant difference between CMS and MRI(p>0.05).According to the t-test of paired samples,there was no statistical difference in fracture displacement between elbow extension and elbow extension(p>0.05).(3)The diagnostic results of X-ray and MRI in children with HLCF were generally consistent(Kappa value=0.576),MRI diagnostic sensitivity was better than X-ray(p=0.031);The two examination methods showed poor consistency in the diagnostic results of trochlear cartilage chain integrity of HLCF(Kappa value=0.123),and the diagnostic sensitivity of MRI was significantly better than that of X-ray(p=0.004).The sensitivity of 3D-FSPGR/3D-FS-FSPGR sequence in the diagnosis of HLCF osteochondral fracture in children was superior to FS-PDWI and FS-T2WI(?~2=7.010,p=0.030);the diagnostic sensitivity of coronal sequence was superior to sagittal and axial sequence,but there was no significant difference between groups(?~2=3.454,p=0.178).The measurements of lateral and posterior fracture displacement on X-ray were less than those on MRI(lateral 2.20±1.22 mm and 2.37±1.38 mm,t=-3.005,p=0.004;posterior 2.26±1.03 mm and 2.41±1.02 mm,t=-2.544,p=0.014);35 cases of HLCF with no significant fracture displacement were divided into unstable fracture group(n=11)and stable fracture group(n=24).MRI found that in the unstable fracture group,5 cases with fracture displacement?2mm were treated with internal fixation;the remaining 6 patients with displacement<2mm were treated with external fixation,then 2 cases which accepted conservative treatment appeared secondary fracture displacement.Stable fracture group were treated with plaster external fixation conservative treatment,and had no secondary fracture displacement.Both groups of cases healed well without serious complications.Conclusions:HLCF is a common child elbow fracture,which is mostly caused by accidental injury.It is necessary to perform the protection education of traumatic injury to children,especially boys aged 3-6 years,which can reduce the fracture incidence.X-ray often underestimates the displacement degree of HLCF;the measurements on MRI are closer to true values than those on X-rays;both elbow flexion and extension have no significant effect on the distance of HLCF gap shift.MRI is superior to X-ray in the diagnostic sensitivity of HLCF fractures and trochlear cartilage chain integrity(fracture stability)and evaluating fracture displacement.Coronary 3D-FSPGR/3D-FS-FSPGR is the best MR sequence for displaying HLCF.Traditional X-ray examination is difficult to accurately determine the stability of HLCF without significant displacment and evaluate the degree of fracture displacement.MRI is a safe and reliable imaging tool for the evaluation of HLCF.MRI can provide important reference value for the clinical treatment decision of HLCF.