The Effect Of Low Limb 15° Internal Rotation In Patients With Hip Disease On Pelvic Tilt In Preoperative AP X-ray Of Pelvis

Objective:Compare the pelvic tilt change between the low limb 15° internally rotation and comfortable position in weightbearing x-rays of pelvis in patients with hip disease and provide reference about preoperative evaluation of pelvic tilt accurately.Methods:Patients were choosen from Joint Surgery Department of Second Hospital of Jilin University from june 2015 to june 2016.61 patients meet the inclusion criteria.Take the lateral x-ray of pelvis in patients with low limb 15° internally rotation and comfortable position(7°externally rotation).Import the images of x-ray into the software Surgimap and take the pelvic parameters(α angle 、PT、SS)into mearsurements.Resultsα angle in 15° internally rotation group is significantly higher compared with comfortable group(4.66°±10.5° VS-0.59°±10.1°,P<0.01).PT in 15° internally rotation group is significantly lower compared with comfortable group(6.67°±10.2° VS 8.93°±9.9°,P<0.01)and SS in 15° internally rotation group is significantly higher compared with comfortable group(42.2°±9.3° VS 38.2°±9.3°,P<0.01).According to the mean value of α change between two low limb position,we set two group named α significantly change group and α not significantly change group.In comfortable group,the α angle in α significantly change group is significantly lower than with the α angle in α not significantly changed group(-3.83°±11.87° VS 3.69°±8.05°,P<0.01).Conclusion1.15° internally rotation of low limb in patients with hip disease when taking the lateral x-ray of pelvis make pelvis tilt anteriorly.2.In comfortable position,15° internally rotation of low limb will make the pelvis of patients with posterior pelvic tilt more anterior compared with patients with anterior pelvic tilt.