Wentao Wang1, Yiqiang Li2, Yueming Guo3, Ming Li4, Haibo Mei5, Jingfan Shao6, Zhu Xiong7, Jin Li8, Federico Canavese9, Shunyou Chen10. 1. Department of Pediatric Orthopedics, FuZhou Second Hospital Affiliated to Xiamen University, 47th ShangTeng Road of CangShan District, FuZhou, 350007, FuJian Province, China. 2. Department of Pediatric Orthopedics, GuangZhou Women and Children's Medical Center, GuangZhou Medical University, GuangZhou, China. 3. Department of Pediatric Orthopedics, Foshan Hospital of Traditional Chinese Medicine, Foshan, China. 4. Department of Pediatric Orthopedics, Children's Hospital of Chongqing Medical University, Chongqing, China. 5. Department of Pediatric Orthopedic, Hunan Children's Hospital, Changsha, Hunan, China. 6. Department of Pediatric Orthopedics, TongJi Hospital of TongJi Medical College Huazhong University of Science and Technology, Wuhan, China. 7. Department of Pediatric Orthopedics, ShenZhen Children's Hospital, Shenzhen, China. 8. Department of Pediatric Orthopedics, Wuhan Union Hospital, Wuhan, China. 9. Department of Pediatric Surgery, University Hospital Estaing, Clermont-Ferrand, France. 10. Department of Pediatric Orthopedics, FuZhou Second Hospital Affiliated to Xiamen University, 47th ShangTeng Road of CangShan District, FuZhou, 350007, FuJian Province, China. csy508@163.com.
Abstract
PURPOSE: To evaluate the correlation between avascular necrosis (AVN) and the amount (severity) and direction (translation and angulation) of initial displacement of pediatric femoral neck fractures. METHODS: We retrospectively reviewed 108 pediatric patients (mean age 10.3 ± 4.1 years) with femoral neck fractures. The amount of initial translation (T) and angulation (A) was measured on anteroposterior (AP; TAP% and AAP) and lateral (TL% and AL) radiographs. The direction of translation was determined on AP (medial or lateral) and lateral radiographs (anterior or posterior). Furthermore, the presence of a comminuted medial cortex on the AP pelvis radiograph was also recorded. Logistic regression analysis, receiver operating characteristic (ROC) curve analysis, student's t tests, and chi-square tests were used to evaluate the correlation between AVN and the severity and direction of displacement. RESULTS: Twenty-eight out of 108 hips (25.9%) developed AVN of the femoral head. Logistical regression analysis indicated that TAP%, TL%, AAP, and AL were risk factors for AVN (P < 0.05). The analysis of ROC curves found that TAP% over 37.4% and TL% over 29% were the cut-off values for an increased incidence of AVN; similarly, AAP over 8° and AL over 18.6° were the cut-off values for an increased incidence of AVN. The amount of initial translation is a better predictor of AVN than angulation is; fractures with posterior translation (P = 0.002) and/or medial comminution had a significantly higher incidence of AVN (P = 0.005). The mean diagnostic accuracy of translation (74-75%) was significantly higher than that of angulation (65-66%). CONCLUSIONS: Displacement severity and direction are important radiological parameters to be assessed in children with femoral neck fractures. Initial translation better predicts AVN than angulation does. Posterior translation and medial comminution are associated with an increased risk of AVN.
PURPOSE: To evaluate the correlation between avascular necrosis (AVN) and the amount (severity) and direction (translation and angulation) of initial displacement of pediatric femoral neck fractures. METHODS: We retrospectively reviewed 108 pediatric patients (mean age 10.3 ± 4.1 years) with femoral neck fractures. The amount of initial translation (T) and angulation (A) was measured on anteroposterior (AP; TAP% and AAP) and lateral (TL% and AL) radiographs. The direction of translation was determined on AP (medial or lateral) and lateral radiographs (anterior or posterior). Furthermore, the presence of a comminuted medial cortex on the AP pelvis radiograph was also recorded. Logistic regression analysis, receiver operating characteristic (ROC) curve analysis, student's t tests, and chi-square tests were used to evaluate the correlation between AVN and the severity and direction of displacement. RESULTS: Twenty-eight out of 108 hips (25.9%) developed AVN of the femoral head. Logistical regression analysis indicated that TAP%, TL%, AAP, and AL were risk factors for AVN (P < 0.05). The analysis of ROC curves found that TAP% over 37.4% and TL% over 29% were the cut-off values for an increased incidence of AVN; similarly, AAP over 8° and AL over 18.6° were the cut-off values for an increased incidence of AVN. The amount of initial translation is a better predictor of AVN than angulation is; fractures with posterior translation (P = 0.002) and/or medial comminution had a significantly higher incidence of AVN (P = 0.005). The mean diagnostic accuracy of translation (74-75%) was significantly higher than that of angulation (65-66%). CONCLUSIONS: Displacement severity and direction are important radiological parameters to be assessed in children with femoral neck fractures. Initial translation better predicts AVN than angulation does. Posterior translation and medial comminution are associated with an increased risk of AVN.