发育性髋脱位闭合复位术前磁共振预判因素分析

目的探讨2岁以内发育性髋关节脱位(developmental dislocation of the hip,DDH)患儿术前磁共振相关因素对手术方式的预判。方法回顾性分析2013年7月至2017年2月收治的57例(60髋)符合条件的发育性髋关节脱位患儿资料,其中男9例,女48例。术中根据Bowen造影标准将患儿分为3组,闭合复位成功为A组(26例),闭合复位失败为B组(24例),无法复位为C组(7例)。在磁共振上测量三组患儿术前关节囊前入口角(anterior access angle,AAA)、下入口角(inferior access angle,IAA)、冠状位最大入口直径(coronal maximal access diameter,CMAD)、轴位最大入口直径(axial maximal access diameter,AMAD)、轴位股骨头直径(axial femoral head diameter,AFHD)、冠状位股骨头直径(coronal femoral head diameter,CFHD)、冠状位口径比(CMAD/AFHD)及轴位口径比(AMAD/CFHD)等指标,比较三组数据的差异有无统计学意义。Logistic多因素回归分析性别、侧别、年龄、脱位程度、负重时间等和治疗方式的相关性,受试者工作特征曲线(Receiver operating characteristic curve,ROC曲线)评估闭合复位组指标的灵敏度、特异度及拐点。结果3组数据的AAA、CFHD、AFHD等方面的差异无统计学意义(P>0.05)。A组IAA角为(108.2±9.8)°,显著大于B组(98.8±11.2)°和C组(91.7±6.9)°,三组差异具有统计学意义(P<0.05);A组与B组,A组与C组在CMAD、AMAD、CMAD/AFHD等的差异具有统计学意义(P<0.05)。A、B两组AMAD/CFHD的差异有统计学意义,A、C两组差异无统计学意义。B、C两组CMAD、AMAD、CMAD/AFHD、AMAD/CFHD的差异均无统计学意义(P>0.05)。根据Logistic多因素回归分析结果,性别、侧别、脱位程度、负重时间等和治疗方式的差异无统计学意义(P>0.05),年龄有相关性。A、B两组差异具有统计学意义的5组数据ROC曲线下最大面积为AMAD/CFHD(0.848),确定AMAD/CFHD的敏感度(74.1%)、特异度(92.3%)及拐点(0.515)。结论术前磁共振指标IAA、CMAD、AMAD、CMAD/AFHD、AMAD/CFHD可作为术前预判因素。当AMAD/CFHD比值>0.515时,建议行闭合复位治疗。

Analysis of preoperative predictive factors of MRI for closed reduction of developmental dislocation of the hip

Objective To explore the influence of preoperative magnetic resonance imaging(MRI)on the choice of operative methods in children aged under 2 years with developmental dislocation of hip.Methods Retrospective analysis was performed for children with developmental dislocation of hip from July 2013 to February 2017.According to the Bowen's radiographic standards,they were divided into 3 groups of closed reduction(A,n=26),failure of closed reduction(B,n=24)and impossibility of reduction(C,n=7).On standard MRI,the preoperative measurement of MRI in joint sacs were anterior access angle,inferior access angle,maximal coronal entrance diameter,maximal axial entrance diameter,axial diameter of femoral head,coronal diameter of femoral head,coronal diameter ratio(CMAD/AFHD)and axial diameter ratio(AMAD/CFHD).And the significant differences of data were compared among three groups.Logistic regression analysis was performed for the correlations of gender,age,degree of dislocation,weight bearing time and final treatment.And receiver operating characteristic(ROC)curve was used for assessing the sensitivity and specificity of closed reduction group and determine the cutoff point.Results No significant difference existed in AAA/CFHD/AFHD among 3 groups(P>0.05).IAA angle(108.2±9.8)°was significantly higher in group A than that in group B(98.8±11.2)°and group C(91.7±6.9)°(P<0.05);significant differences in CMAD,AMAD,CMAD/AFHD existed between groups A&B and groups A&C(P<0.05).AMAD/CFHD were different in groups A&B;there was no statistical difference between group A/C;CMAD,AMAD,CMAD/AFHD,AMAD/CFHD were not statistically different between groups B&C(P>0.05).Logistic regression analysis revealed that,except for age,no correlation existed in gender,measurement,degree of dislocation,weight bearing time or final treatment(P>0.05).The maximal area of ROC curve was 0.515(AMAD/CFHD),its specificity(92.3%)and inflection point(0.515).Conclusions Preoperative measurements of MRI of IAA,CMAD,AMAD,CMAD/AFHD,AMAD/CFHD offer certain guiding values for treatment.When AMAD/CFHD ratio is>0.515,closed reduction is recommended.