基于CT断层影像的髋关节假斜位X线片拍摄中骨盆旋转角度验证标准的研究

The verification standard of rotation angle of hip false profile X-ray film based on CT scan

目的探讨髋关节假斜位片拍摄时旋转角度的验证标准,结合其解剖学基础,分析其合理性与科学性。方法回顾性研究。纳入2015年6月— 2019年12月南京医科大学第一附属医院骨科关节病区所收治的219例股髋撞击征患者(男102例、女117例,年龄18 ~ 46岁)的CT扫描数据,建立假斜位拍摄时的骨盆旋转标准化数学模型,对健侧和患侧股骨头直径(Φ)、实际双侧股骨头间距离(AFHD)、双侧股骨头间投影距离(PFHD)等参数进行测量和公式计算。分别以PFHD/Φ为0.67~1和1~2为校正标准,观察骨盆旋转和骨盆解剖特点对假斜位片拍摄的影响。结果当骨盆冠状面与底片成65°角时,本组219例患者CT影像测量结果为:股骨头直径(4.37±0.43)cm,PFHD(3.79±0.30)cm,AFHD(18.70±3.15)cm,PFHD/Φ 0.87±0.15,AFHD/Φ 4.40±0.98。219例患者同性别组内左右两侧股骨头直径比较,差异均无统计学意义(P值均>0.05);男性左、右侧股骨头直径均大于女性,女性PFHD、AFHD、PFHD/Φ及AFHD/Φ值均大于男性,差异均有统计学意义(P值均<0.01)。当以PFHD作为假斜位片拍摄时旋转角度的验证标准时,按照Lequesne的标准,PFHD/Φ的取值在0.67~1时,骨盆与底片盒成角的范围是60°~70°,其中成角为60°、65°和70°的样本分别占样本总数的30.59%(67/219)、57.53%(126/219)和19.63%(43/219);当以PFHD/Φ的取值为1~2作为验证标准时,骨盆与底片盒成角的范围是45°~65°,其中成角为45°、50°、55°、60°和65°的样本分别占样本总数的85.39%(187/219)、100%(219/219)、100%(219/219)、71.23(156/219)和4.11%(9/219)。通过建立数学模型可知PFHD/Φ的取值满足公式FHD/Φ=ncos 65°/2-1。结论拍摄假斜位片时,以PFHD/Φ作为验证标准,如果PFHD/Φ取值大于1,则n需要取值大于9.52,即解剖上需满足AFHD大于9个股骨头半径;而如果PFHD/Φ要取值为2,则n需要取值为13.89,即解剖上需满足AFHD大于13个股骨头半径。故根据人类骨盆AFHD的平均值来判断,Lequesne将PFHD/Φ的取值范围定为0.67~1具有一定的合理性,但存在一定误差;而将PFHD/Φ的取值范围定为1~2的验证标准缺乏合理的解剖学依据。

Objective To explore the verification standard of rotation angle of hip false profile film and analyze its rationality and scientificity based on its anatomy.Methods A retrospective analysis of 219 patients'CT scan data(male 102,female 117,age 18-46)with femoroacetabular impingement from June 2015 to December 2019 from the Department of Orthopaedics,Jiangsu Province Hospital was conducted to establish the standardized mathematical model of pelvis rotation in false profile position.The diameter of the femoral head(Φ),the actual distance between the two femoral heads(AFHD),the projection distance between the two femoral heads(PFHD),and other parameters were measured and calculated to determine the impact of the pelvic rotation and the anatomical characteristics of the pelvis on the false profile film.Results When the angle between the pelvis and the film was 65°,the CT scan results of the 219 patients showed that the diameter of femoral heads was(4.37±0.43)cm,the PFHD was(3.79±0.30)cm,the AFHD was(18.70±3.15)cm,the PFHD/Φwas 0.87±0.15,and the AFHD/Φwas 4.40±0.98.The diameter of the left and right femoral heads of 219 patients in the same sex group showed no statistically significant difference(all P values>0.05).The diameter of the left and right femoral heads was significantly larger in males than in females,and the PFHD,AFHD,PFHD/Φ,and AFHD/Φvalues were significantly larger in females than in males(all P values<0.01).When the projection distance between the two femoral heads(PFHD)was used as the verification standard of the rotation angle of the false profile film,the range of angles between the pelvis and the film box was 60°-70°,in which the angles of 60°,65°,and 70°accounted for 30.59%(67/219),57.53%(126/219),and 19.63%(43/219)of the total number of samples,respectively,according to Lequesne's standard.This result indicates that the PFHD/Φvalue should be between 0.67 and 1.When a PFHD/Φvalue of 1-2 was used as the verification standard,the range of angulation between the pelvis and the film box was 45°-65°,among which the angulation of 45°,50°,55°,60°,and 65°accounted for 85.39%(187/219),100%(219/219),100%(219/219),71.23(156/219),and 4.11%(9/219)of the total number of samples,respectively.Conclusions When the false profile film is taken,PFHD/Φas the verification standard has certain anatomical basis.The Lequesne index may set the PFHD/Φas 0.67-1,but a certain error exists.Setting the validation standard of PFHD/Φto 1-2 has no reasonable anatomical basis.