Session VI - Pediatrics
Risk Factors for Avascular Necrosis following Femoral Neck Fractures in Children: A Meta-analysis of 360 Cases
Purpose: Avascular necrosis (AVN) is one of the most serious complications of femoral neck fractures in children. Variability in the reported rates of AVN and lack of statistical evidence has minimized the prognostic power of individual studies. The purpose of our study was to review our own cases as well as those from the literature in an effort to identify AVN risk factors.
Methods: We conducted a computerized medical records search to identify all children with femoral neck fractures treated at our institution from 1980 to 2003. Records were reviewed to determine fracture type (Delbet type I to IV), displacement, age, treatment, and incidence of AVN. A structured search of PubMed was also performed to identify all reports published in English on femoral neck fractures in children from 1965 to 2003. Manual searches of major orthopaedic journals and reference lists of publications identified additional cases. Of the 275 citations initially identified through our computerized search, 47 met the criteria for further evaluation. These citations were reviewed by two investigators and data were abstracted from 22 reports that provided patient level data and met our criteria for inclusion.
Results: 24 patients with femoral neck fractures from our institution were identified, including 12 males and 12 females with an average age of 8 years (range, 2 to 16 years). Over 300 patients who met our study criteria were also identified from the literature. A total of 360 patients were included for analysis. Fracture type, displacement, age, and treatment were all statistically significant independent predictors of AVN with P values 0.05. With logistic regression analysis, however, fracture type and age were identified as the only significant predictors of AVN. Older children were 1.13 times more likely to develop AVN for each year of increasing age. Type I to III fractures were 11, 6, and 3 times more likely than type IV fractures to develop AVN respectively. AVN rates by Delbet class were I = 38%, II = 28%, III = 18%, and IV = 5%.
Conclusion/Significance: Although several factors may contribute to the development of AVN, our meta-analysis provides statistical evidence that fracture type and age are the most significant predictors.