Quantification of Patellar Maltracking Combined with J-Sign Using Computed Tomography
10.3969/j.issn.1000-6710.2017.09.001
- VernacularTitle:计算机断层扫描量化伴有J形征的异常髌骨轨迹
- Author:
Zhe XUE
1
;
Guanyang SONG
;
Xin LIU
;
Hui ZHANG
;
Yi QIAN
;
Hua FENG
Author Information
1. 北京积水潭医院运动损伤科 北京100035
- Keywords:
recurrent patella dislocation;
knee J-sign;
patella bisect offset index;
patella trochlear-groove distance;
patella lateral tilt
- From:Chinese Journal of Sports Medicine
2017;36(9):751-755
- CountryChina
- Language:Chinese
-
Abstract:
Objective To quantify the patellar mal-tracking combined with J-sign using the computed tomography (CT).Method Fifty-three adult patients diagnosed as recurrent patellar dislocation (RPD) were chosen.According to their patellar tracking during knee active flexion and extension,they were divided into group A(with positive J-sign) and group B(with negative J-sign).The CT examinations were performed in all patients at 0°extension of the knee and the patella bisect offset index (BOI),patella troehlear-groove distance (PTG) and patella lateral tilt (PLT) were measured in the axial position and compared.The receiver operating characteristic analysis (ROC) curve was used to analyse the accuracy and stability of the three J-sign parameters.Results In all the 53 patients,thirty-seven(69.8％) knees were of positive J-sign,while the rest 16 were of negative J-sign.The mean values of CT parameters BOI,PTG and PLT in group A were significantly larger than those of group B.Moreover,the area under the curve for BOI,PTG and PLT were 0.906,0.883 and 0.833 respectively.The sensitivity and specificity of BOI were 83.3％ and 87.5％,while the predicting cut-off value was 97.5％.Conclusion In all the 53 recurrent patella instability patients,the morbidity of patella proximal mal-trackingis 69.8％.The CT parameter BOI can be used to quantify the J-Sign into positive and negative groups.
