title: Prediction of osteonecrosis collapse of the femoral head based on the proportion of the proximal sclerotic rim.
abstract: OBJECTIVE
  The purpose of this study was to predict ONFH-induced collapse based on the percentage of the proximal sclerotic rim.
  
  
  METHODS
  In total, 101 patients satisfying the inclusion criteria who received treatment at Guang'anmen Hospital were enrolled. Bilateral hip-joint computed tomography (CT) of the necrotic tissue was performed, and the largest layer within the coronal CT images was selected together with its anterior and posterior layers to calculate the proportion of the proximal sclerotic rim. The patients were divided into collapse and non-collapse groups, and the difference in the proportions of their proximal sclerotic rims was analysed. Specifically, a receiver operating characteristic (ROC) curve was created. The proportion of the proximal sclerotic rim represented by the maximal Youden's index was used as the reference value for collapse prediction, and its predictive value was assessed.
  
  
  RESULTS
  The proportion in the collapse group was 13.11 ± 10.65 %, whereas the proportion in the non-collapse group was 51.91 ± 21.29 % (P < 0.01). Additionally, the proportion corresponding to the maximal Youden's index (0.902) was 29.24 %. For clinical convenience, 30 % was selected as the reference value for collapse prediction, with 97.30 % sensitivity, 87.5 % specificity, 94.01 % accuracy, a positive likelihood ratio (LR) of 7.78, and a negative LR of 0.03. Therefore, the proportion of the proximal sclerotic rim is of great significance in predicting ONFH-induced collapse, and 30 % could be used as the critical value in clinical practice.
  
  
  CONCLUSIONS
  When the proportion is >30 %, the collapse risk is low, whereas at <30 %, the risk is high, and effective mechanical support should be provided.
authors.affiliation: Department of Orthopaedics, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Yu
authors.forename: Limin
authors.initials: L
authors.lastname: Xie
authors.forename: Zhennan
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xun
authors.initials: X
authors.lastname: Ke
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging / Q000473:pathology*; D005271:Femur Head Necrosis / Q000175:diagnosis / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000150:complications* / Q000175:diagnosis; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*