| Part 1 To analyze the performances and the related measurement values of femoro-acetabular impingement on MSCTObjective:To investigate the performances and characteristics of femoro-acetabular impingement(FAI)on MSCT.Methods:hips jointed MSCT scans of 109 cases(as case group)and the other 120 cases(as control group)were analyzed retrospectively,to analyze the anatomy and osseous abnomality of FAI.Alpha angle,offset,CE angle were measured.The data was tested by using t test and ANOVA test.Results:There are 57 cases of osseous protuberance at the femoral head and neck joint,26 cases of the offset reduction,17 cases of over-coverage acetabulum,41 cases of over-deep acetabulum,20 cases of acetabular retroversion,57 cases of subcortical cystic degeneration at the femoral head and neck joint and 22 cases of subchondral cystic degeneration at the acetabulum margin.Significant statistical differences were found between case group and control group in alpha angle value,offset and CE angle(P<0.05).Multiple comparisons demonstrated that except results between the value of alpha angle of Cam-type and Mixed-type(p=0.071),pincer-type and the control group(p=0.083)with no statistical significance,the differences between any other two groups reached statistical significance(P<0.05).Multiple comparisons demonstrated that except result between the value of offset of Cam-type and Mixed-type(p=0.561)with no statistical significance,the differences between any other two groups reached statistical significance(P<0.05).Multiple comparisons demonstrate that except result between the value of CE angle of pincer-type and Mixed-type(p=0.444),Cam-type and the control group(p=0.236)with no statistical significance,the differences between any other two groups reached statistical significance(P<0.05).Conclusion:Different type of FAI has its unique anatomical features.Alpha angle,offset and CE angle for the diagnosis of FAI have important reference value.Part 2 To Investigate The Alpha Angle Of Cam-type Femoro-acetabular Impingement(FAI)estimated by means of the multiple radial plane protocolObjective:To investigate the alpha angle of cam-type femoro-acetabular impingement(FAI)estimated by means of the oblique axial and multiple radial plane protocol were compared with the computed results.Methods:30 cases with clinical diagnosis of cam-type FAI were treated as case group and the other 30 cases with asymptomatic were treated as control group,hips jointed MSCT scan and three-dimensional reconstruction to assess the images of the oblique axial and multiple radial plane protocol.The data was tested by ANOVA test.to draw the receiver operating characteristic(ROC)curve.Results:The value of alpha angle of Cam-type on the control group was no statistical significance(p>0.05).The mean alpha angle value of the case group on the oblique axial plane was(52.56±0.86)°.Alpha angle greater than 55°was found in 50 joints of 23 cases(46%,23/50).The mean alpha angle values at the 12,1,2,3 o' clock position were(56.65±0.92)°,(66.34±1.21)°,(64.93±1.20)°,(52.70±0.86)°,respectively.148 Alpha angle greater than 55° in total were found on the radial plane images.The mean alpha angle values at the 1,2 o' clock position were greater than others.The Alpha angle greater than 55° in total were found at the 1,2 o' clock position,including 86~88%(43~44 /50)of the subjects.Significant statistical differences were found between the oblique axial and multiple radial plane protocol on case group in the alpha angle value(p< 0.05).Multiple comparisons demonstrate that except result between the value of alpha angle on the 1 o' clock and 2o' clock,oblique axial and 3 o'clock,the others was statistical significance.The areas under receiver operating characteristic(ROC)curve of the alpha angle on the oblique axial and multiple radial plane protocol were 0.959,0.981,0.996,0.998,0.966,respectively.The diagnostic threshold values of the different levels were 44.05~45.57°,46.77~48.72°,51.48~52.22°,49.94~51.91°,42.33~43.79°,respectively.The sensitivity and the specificity were greater than 90° in 12,1,2 o' clock position,which were greater than the oblique axial plane(50°or55°).Conclusion :The morphological changes of the femoral head-neck junction were more sensitive on the multiple radial plane protocol.The diagnosis of alpha angle remains to be explored with a large sample,so as to set a more reasonable diagnostic threshold.Part 3 Preoperative Three Dimensional CT Simulation of Cam type Femoro-acetabular Impingement(FAI)Resection AreaObjective:Three dimensional CT was used to simulate the resection range of Cam type femoro-acetabular impingement patients and to guide the scope of arthroscopic surgery,inorder to reduce the probability of failure or the need for revision surgery.Methods:Retrospective analysis of 30 cases,50 sides.hips jointed CT scanning and reconstructed impact level,respetively.Measured a angle,a angle after resection and the distance between the highest point of the bony prominence and the normal femoral head edge on the oblique axial;and the arc length L1,the angle of the bone changes area,the femoral head diameter of the bone changes area on the oblique axis and short axis,respetively.Data were processed by SPSS19.0 software,comparison of a angle before and after resection with the paired samples t-test;consistently analyzed the impact zone and the measurement of the arc length L1 on the maximum impact plane;The correlation analysis of the region of the impact plane and the radius and the angle on the maximum impact plane was analyzed by linear correlation coefficient,P < 0.05 considered to be statistical significance.Results:The difference of paired t test before and after resection of a angle was statistically significant(P < 0.001).the arc length of the femoral head on the oblique axis and the short axis position were positively correlated with the included angle and diameter(P < 0.001);Highly consistent with the proposed arc length(ICC>0.9).Preoperative Three dimensional reconstruction of CT can accurately display the anatomy of bone abnormalities and simulate the range of bony impingement,which has a certain guiding significance for clinical resection. |
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