应用足底平面第一与第五跖骨夹角评价胎儿先天性足内翻

Value of the angle between the first and fifth metatarsal bones on plantar plane in prenatal diagnosis of fetal congenital clubfoot

目的：探讨测量足底平面第一与第五跖骨夹角在诊断先天性足内翻中的价值。方法：对照组选择孕周为19~37周的117例胎儿共186只胎足,病例组选择先天性足内翻的24例胎儿37只胎足,应用TUI模式显示足底平面并测量第一与第五跖骨夹角,分析正常胎儿该角度与其孕周的相关性,并比较两组之间该角度的差异;同时利用ROC曲线判断其诊断价值。对病例组胎儿于其出生或引产后进行随访并进行DR检查,于正位片上测量第一与第五跖骨夹角,并将超声测量结果与DR测量结果进行对比分析及一致性检验。结果：对照组第一与第五跖骨夹角为（22.83±2.07）°,与孕周无明显相关性（r=0.104,P=0.158〉0.05）。病例组第一与第五跖骨夹角的测量结果为（32.91±3.30）°,与对照组相比差异有统计学意义（P=0.000〈0.05）。ROC曲线下面积为0.978,曲线上的最佳临界点为27.47°,对应的敏感度为94.6%,特异度为97.8%。正常足与内翻足的DR正位片测量结果分别为（23.28±1.16）°、（33.59±3.02）°,超声测量结果与之相比差异均无统计学意义（P=0.471〉0.05,P=0.281〉0.05）。一致性检验所得Kappa值分别为0.811和0.894（P=0.000〈0.05）,说明二者诊断的一致性较好。结论：正常胎儿足底平面第一与第五跖骨夹角与孕周无明显相关性。先天性足内翻胎儿第一与第五跖骨夹角与正常胎儿相比角度明显增大。

Objective： Discuss the value of the angle between the first and fifth metatarsal bones on plantar plane in di- agnosis of fetal congenital clubfoot. Methods： There were 186 feet of 117 fetuses with gestational age from 19 to 37 weeks in control group. There were 37 feet from 24 fetuses which were suspected with congenital clubfoot in case group. Use TUI mode to measure the angle between the first and fifth metatarsal bones on plantar plane, and analyze the correlation between the angle and the gestational age. Compare the results with the case group and use ROC curve to judge its diagnostic value. The fetuses in case group were followed to obtain the pregnancy outcomes and confirm whether the deformity existed. DR ex- amination was used to measure the angle of bilateral feet of the fetuses with congenital clubfoot on postero-anterior view. Compare the results with ultrasonic measurement and calculate Kappa value. Results： The angle between the first and fifth metatarsal bones on plantar plane in control group was （22.83±2.07）°. It had no obvious correlation with gestational age （r= 0.104, P=0.158〉0.05）. The angle of case group was （32.91±3.30）°, and compared with control group, the difference is statisti- cally significant （P=0.000〈0.05）. The area under ROC curve was 0.978, the cut-off was 27.47° with sensitivity of 94.6% and specificity of 97.8%. The angle of normal feet and clubfoot under DR check were （23.28±1.16）°, （33.59±3.02）°, the differences had no statistically significant between ultrasonic measurements and DR cbeck（P=0.471〉0.05, P=0.281〉0.05）. The Kappa value of measure of agreement were 0.811 and 0.894 （P=0.000〈0.05）. Conclusions： The angle between the first and fifth metatarsal bones on plantar plane has no obvious correlation with gestational age. Compare to the normal fetuses, the angle of fetal con- genital clubfoot between the first and fifth metatarsal bones increases obviously.