The Linear Correlation And Regression Analysis Of Pelvic Tilt And Acetabular Anteversion In Adults Group

Objective: Correct orientation of the acetabular component during total hip arthroplasty(THA)is fundamental since it is important for functioning with range of motion,dislocation,impingement and wear.Pelvic sagittal rotation(pelvic tilt,PT)affects functional orientation of the acetabulum,as acetabular anteversion(AA)decreases with anterior tilting of the pelvis.The change of individual’s positions causes pelvic sagittal rotations.The doctors should know the exact changes of AA caused by the pelvic sagittal rotations.The aim of this study is to quantify the relationship between pelvic tilt and acetabular anteversion(AA)measured on a CT scan in supine position and to explore whether gender related differences furtherly exist or not.Methods: 61 young healthy volunteers were included in this study.Inclusion criteria:from18 to 50 years old;from 150 cm to 190 cm height;BMI from 18.5 to 25.Exclusion criteria: younger than 18 years old or older than 50 years old;shorter than 150 cm or higher than 190 cm height;heavier than100 Kg or lighter than 40Kg;history of pelvic fractures;deformity of spine,pelvic or hip;unequal length of two legs;unable to cooperate with doctors;long time engagement in heavy lavor.Pelvic tilt and AA of the 61individuals’ were measured by computed tomography(CT).The data of pelvic tilt and AA were analysed by linear correlation and regression analysis with spss17.0.Results: The pelvic tilt was 27.92±4.885°(from 17°to 39°).Males showed greater angles of pelvic tilt compared to females(29.74° vs 26.07°,P=000).The AA was 17.66±4.01°(from 9°to 27°).AA displayed no gender related differences.Pelvic tilting showed a positive correlation with AA and this observation was more pronounced in females(correlation coefficient of all=0.624,correlation coefficient of males=0.441,correlation coefficient offemales=0.823,t=-3.74,P=0.000.Regression coefficient of all=0.512,regression coefficient of females=0.683,regression coefficient of males=0.427,t=-6.74,P=0.000).Conclusions: There is a positive correlation between pelvic tilt and AA and the correlation coefficient is more pronounced in females.The change in AA is approximately 0.5°(female 0.7° while male 0.4°)with 1° pelvic rotation and the varied range of females is greater than that of males.