The Value Of Bilateral Frog X-ray In Evaluating The Cam Deformity Of The Femoral Head And Neck

Objective: Our study measured the alpha angle of the formal neck on bilateral frog X-ray,and compared it with the alpha angle measured on the radial plane image reconstructed with the CT data,to determine the value of bilateral frog radiographs in evaluating the cam deformity of the femoral head and neck.Methods: a retrospective analysis from January 2016 to June 2017 in our hospital by clinical and imaging examination and diagnosis of 36 cases of cam hip impingement syndrome patients(56 hips),including 20 cases of bilateral hip,16 cases of single hip,access to the 36 cases of patients with bilateral frog X-ray image and hip CT original DICOM data.The DICOM data acquisition CT into MIMICS software,with the long axis of the proximal femoral shaft direction for 12 o'clock direction,radial plane images were reconstruction of 12 o'clock direction,1 o'clock direction,2 o'clock direction and 3 o'clock direction.Use Digimizer V4.3.4 software to depict the femoral neck alpha angle and measurement will get four gain level and the radial image of bilateral frog X-ray images,record and collect measurement data at all levels.The research is self controlled study,according to the different image levels of image is divided into double hip frog and the radial direction of the12 o'clock,1 o'clock 3 o'clock group,a total of 5 groups.All the data were analyzed using Medcal V18.2.1 software,LSD method was used to compare the different plane between the measured femoral neck alpha angle results,analyze the consistency of the data with the radial angle alpha level of the most sensitive data measured by the measurement of bilateral frog radiograph by Bland-Altman analysis.Results: According to the different levels of the images were divided into bilateral frog radiographs group,radial level group:12 o'clock 1 o'clock 2 o'clock 3 o'clock,group,group direction group,a total of 5 groups.The results were measured by mean + standard deviation((X + S)to statistics,the bilateral frog a femoral neck alpha angle measurement results for(62.57 + 4.05)°at the femoral neck,alpha angle measured more than 55°angle is 51,the radial plane femoral neck alpha angle of 12 points to 3 points angle measurement results for:(54.10 + 3.44),(63.86 + 4.03),(62.90 + 4.36),(51.41 + 4.55)degrees.Multiple groups of data between comparison: between the three group and bilateral frog bit level group and the level of the 1 o'clock 2 o'clock 22 there was no significant difference between the other groups(p>0.05),the differences were statistically significant(p<0.05).Using Bland-Altman analysis method to analyze the consistency of the data with the radial angle alpha level of the most sensitive data measured on radiographs obtained on bilateral frog,frog a frog bit slice group and bilateral radial level group and group level 1 o'clock 2o'clock were highly consistent.Conclusion: The results of this study found that the maximal ?-angle of the femoral neck of the Cam type FAI appears mostly at the radial level in the 1-2 o'clock direction(anteriorly above).In addition,by comparing the measurement results on the ?-angle on the bilateral frog X-ray and radial planes,it was found that there is no difference between the measurement results on the alpha angle of the femoral neck on the bilateral frog X-ray and the measurement results at the 1-2 o'clock on the radial plane Statistical significance,and with them all have a high degree of consistency,to some extent that the bilateral frog X-ray can effectively show the 1-2 o'clock direction of deformity,and this position is the most common type of Cam type FAI deformity Occurrence of the site,indicating that the bilateral frog X-ray can appear in the femoral head and neck cam deformity for effective assessment.