儿童单侧发育性髋关节脱位双下肢差异统计及其影响因素

Statistics on difference in length of lower limbs and its influencing factors in children with unilateral developmental dislocation of the hip

目的测量并分析儿童单侧发育性髋关节脱位(Unilateral developmental dysplasia of the hip,UDDH)健侧与患侧影像学下肢差异的特点,包括下肢长度差异(Leg length discrepancy,LLD)、股骨颈前倾角(Femoral neck anteversion,FNA)以及股骨颈干角(Neck shaft angle,NSA)差异。方法回顾分析2018年1月至2021年6月符合纳入标准的120例UDDH患者临床影像学资料。UDDH根据Tonnis分型,分为Ⅰ、Ⅱ、Ⅲ、Ⅳ型。摄站立位骨盆股骨全长X线、骨盆股骨CT,测量以下参数:股骨长度(Femoral length,FL)、大转子股骨长度(Greater trochanter femoral length,GTFL)、小转子股骨长度(Lesser trochanter femoral length,LTFL)、干骺端股骨长度(Metaphysis femoral length,MFL)、大小转子间距离(Intertrochanteric distance,ITD)、FNA、NSA。比较健侧患侧上述参数,并计算各参数健患侧差值;分别统计上述参数健侧较患侧长以及患侧较健侧长的例数;比较各影像学参数健患侧差值在不同Tonnis分型、年龄、性别之间的差异。结果患侧FNA、NSA、MFL、LTFL均大于健侧,差异均具有统计学意义(P<0.05);健侧FL、GTFL和ITD大于患侧,差异具有统计学意义(P<0.05);FNA、NSA、LTFL、MFL患侧大(长)构成比大于健侧大(长)构成比;FL、GTFL和ITD健侧长构成比大于患侧长构成比。根据不同模型多元线性回归统计,Mod1中NSA、MFL患健侧差值均随年龄增加而减少(P<0.05),在Mod2、Mod3中同样具有统计学意义(P<0.05)。在Mod4、5、6中FL患健侧差值均随脱位程度增加而减少,具有明显统计学意义(P<0.05),脱位程度越高,患侧FL越小于健侧。患健侧NSA差值随着年龄增大而减小,患侧NSA随着年龄增大逐渐趋近于健侧,甚至会小于健侧。无论脱位程度如何,患侧MFL均大于健侧MFL;脱位程度越大,患侧FL越小于健侧FL。结论患侧FL较健侧短,但相差值很小,没有实际临床意义;而患侧MFL明显大于健侧,说明术前UDDH患者确实存在LLD;患侧FNA、NSA较健侧显著增大,但增加的数值较小,其临床意义还有待进一步研究;患健侧FNA差值不随年龄增大而减少,患侧与健侧NSA的差值与年龄呈负相关。

Objective To measure and analyze the characteristics of the radiographic lower limb differences between the unaffected side and the affected side in children with unilateral developmental dysplasia of the hip(UDDH),including leg length discrepancy(LLD),femoral neck anteversion(FNA)and femoral neck shaft angle(NSA)differences.Methods The clinical imaging data of 120 patients with UDDH who met the inclusion criteria from January 2018 to June 2021 were retrospectively analyzed.According to the Tonnis classification,UDDH is divided into type i,ii,iii,and iv.The standing position pelvic femoral full-length X-ray and pelvic femoral CT were taken,and the following parameters were measured:Femoral length(FL),greater trochanter femoral length(GTFL),lesser trochanter femoral length(LTFL),metaphysis femoral length(MFL),intertrochanteric distance(ITD),FNA and NSA.The above parameters of the healthy side and the affected side were compared,and the difference between the healthy and affected sides of each parameter was calculated.The number of cases in which the healthy side of the above parameters was longer or shorter than the affected side was counted respectively.The differences of imaging parameters between healthy and affected sides were compared among different tonnis types,ages and genders.Results The FNA,NSA,MFL,and LTFL on the affected side were larger than those on the healthy side,and the differences were statistically significant(P<0.05);On the contrary,the FL,GTFL,and ITD on the healthy side were larger than those on the affected side,and the differences were statistically significant(P<0.05).In FNA,NSA,LTFL,and MFL,the larger(longer)constituent ratio of the affected side was greater than those of the healthy side,and the longer constitutive ratio of the healthy side was greater than those of the affected side in FL,GTFL,and ITD.According to the multiple linear regression statistics of different models,the difference between the NSA and MFL affected side in mod1 decreased with age(P<0.05),and also statistically significant in mod2 and mod3(P<0.05).In mod4,5,6,The FL difference between the affected side and the healthy side decreased with the increase of the degree of dislocation,which was statistically significant(P<0.05).The higher the degree of dislocation,the smaller the FL of the affected side than the healthy side.The NSA difference of the affected side and the healthy side decreased with age,and the NSA of the affected side gradually approached that of the healthy side,or even was smaller than that of the healthy side.Regardless of the degree of dislocation,the MFL of the affected side was larger than the MFL of the healthy side,and the FL of the affected side was smaller than the FL of the healthy side as the degree of dislocation increased.Conclusion The FL of the affected side was shorter than that of the healthy side,but the difference was very small and had no actual clinical significance;While the MFL of the affected side was significantly larger than that of the healthy side,indicating that there was indeed LLD in patients with preoperative UDDH.The FNA and NSA of the affected side increased significantly compared with the healthy side,but the increased value was small,and its clinical significance needs further study.The difference of FNA of the affected side did not decrease with age,and the difference of NSA between the affected side and the healthy side negatively correlated with age.