Risk factors for avascular necrosis in pediatric femoral neck fractures: a systematic review and meta-analysis.

Abstract

Avascular necrosis (AVN) is a severe complication following pediatric femoral neck fractures (PFNFs). Identifying risk factors for AVN is critical for guiding timely treatment and follow-up. However, prior studies report inconsistent associations. This systematic review and meta-analysis aimed to identify risk factors associated with AVN after PFNFs. A comprehensive literature search was conducted in PubMed, Web of Science, EMBASE, and the Cochrane Library through April 30, 2025. Risk ratios (RRs) with 95% confidence intervals (CIs) were calculated to assess the association between potential risk factors and AVN. Leave-one-out sensitivity analyses, meta-regression, and subgroup analyses were performed. Thirty-four studies comprising 1332 pediatric patients (1340 fractures) were included. Older age (≥ 12 years; RR = 1.40, 95% CI 1.09-1.82), Delbet type I/II fractures (RR = 1.96, 95% CI 1.60-2.39), initial displacement (RR = 2.98, 95% CI 2.04-4.35), and poor reduction quality (RR = 2.43, 95% CI 1.46-4.05) were significantly associated with increased AVN risk. Gender, injury mechanism, time to reduction, and reduction method showed no overall association. Meta-regression identified follow-up duration as a significant moderator. Subgroup analyses of long-term follow-up (≥ 5 years) revealed that delayed reduction increased AVN risk (RR = 2.63, 95% CI 1.35-5.11), while closed reduction and internal fixation (CRIF) reduced risk compared to open reduction (RR = 0.40, 95% CI 0.24-0.65). Subgroup differences between long-term and short-term follow-up were both statistical significant. Older age, Delbet type I/II classification, initial displacement, and poor reduction quality are significant predictors of AVN following PFNFs. Early reduction and CRIF may provide superior long-term outcomes. Further high-quality prospective studies with extended follow-up are needed to confirm these findings.