Experimental Analysis Of Measurement Of Sagittal Pelvic Mal-rotation On The Pa Pelvic Radiograph

ObjectivePreliminary summarized the relationship between the obturator ratio（obturator ratio was defined as the tallest height over the widest width ofthe obturator foramen）and pelvic obliqueness angle，Provide the basis forthe determination of the position of the acetabular implant for total hiparthroplasty.MethodsThe obturator foramen ratios of the8pelvis were measured in pelvicposteroanterior X-Ray when facing the11different pelvic obliquenessangles，and measuring80cases of normal adult volunteers’ obturatorforamen ratios.ResultsThe pelvic obliqueness angle and the obturator foramen ratio showedthe positive linear correlation by the linear regress analysis(r=0.9945, P= 0.000), and the linear regression equation was Y=1.1046+0.0239X. Thenormal adult volunteers’ obturator foramen ratio was1.03±0.16.ConclusionBased on the results of the study, the inclination of pelvis was impactof the shape of the obturator foramen. obturator foramen ratio increaseswhen the rearward degree of rotation increase in the sagittal plane. Theresults provided reliable anatomical basis for total hip arthroplastyespecially patients with ankylosing spondylitis. The normal adultvolunteers’ obturator foramen ratio was1.03±0.16, it was no statisticallysignificant difference with the average obturator foramen ratio when theobliqueness angle was0°.