成人非典型大骨节病距骨坏死踝关节X线改变特点及ROC曲线分析

Radiographic changes of atypical adult Kashin-Beck disease talus necrosis and ROC curve analysis

目的探讨成人非典型大骨节病(KBD)距骨坏死X线改变特点以及和缺血性距骨坏死鉴别诊断的有效指标。方法对35例(35踝)距骨坏死患者进行研究,根据距骨坏死诊断分为成人非典型KBD距骨坏死组(KTN组,16踝)和缺血性距骨坏死组(ATN组,19踝)。调取患者病历及影像学资料(dicom格式),采用Radi Ant 1.1.8软件(评估版)进行踝关节X线测量并对比分析;具有统计学差异的检查指标进行ROC分析确定其特异度和灵敏度。结果踝关节X线检查表明跟骨Bhler角、Gissane角、跟骨长高比值以及跟距骨长度比值对两种距骨坏死的鉴别诊断无明显意义(P>0.05)。KTN患者跟骨长度、跟骨高度、距骨长度均明显低于ATN患者,踝关节远端膨大率明显高于ATN患者(P<0.05)。ROC曲线表明踝关节远端膨大率可作为KTN诊断的有效指标,cut off值为1.324时对应灵敏度为0.750,特异度为0.842;单纯跟骨、距骨长度不能作为KTN诊断的有效指标。结论成人非典型KBD距骨坏死单纯依赖跟骨短、扁特点不能和缺血性距骨坏死有效鉴别,踝关节远端膨大率(cut off值1.324)可做为鉴别诊断的有效指标,>1.324可基本确定为KTN。

Objective To evaluate the ankle radiographic characters of adult atypical Kashin-Beck disease（ KBD） talar necrosis and certify the effective indictor for its＇ diagnosis by ROC curve analysis. Methods 35 patients（35 ankles） with talus necrosis patients were enrolled in the study. Two groups were divided according to the diagnosis into adult atypical KBD talus necrosis group（ KTN group,16 ankles） and aseptic talus necrosis group（ ATN group,19ankles）. The medical records and ankle radiography（ dicom format） were reviewed and measured by using Radi Ant1. 1. 8 software（ evaluation version）. The radiography data were compared and the values with significant difference were further analyzed by ROC curve analysis to determine the specificity and sensitivity. Results Ankle X-ray showed calcaneal Bhler angle,Gissane angle,calcaneal length and height ratio,and length ratio of the calcareous and talus all had no statistical difference between the two groups（ P〉0. 05）. KTN patients had a shorter calcaneal length and height and talar length,and larger distal ankle expansion ratio compared to the ATN patients（ P〈0. 05）.ROC curve analysis indicated the distal ankle expansion ratio was an effective indicator for KTN diagnosis,cut off value of 1. 324 corresponds to a sensitivity 0. 750 and specificity 0. 842; calcaneal length and height and talus length cannot serve as a valid indicator of the KTN diagnosis. Conclusions Adult atypical KBD talar necrosis cannot be diagnosed simply by the calcaneus short and flat characteristics. The distal ankle expansion rate（ cut off 1. 324） can be preferred as an effective indicator for differential diagnosis,in which diagnosis can be certified if the ratio is greater than 1. 324.