Purpose: Femoral neck fractures in children represent less than 1% of all paediatric fractures. Osteonecrosis of the femoral head is one of the devastating complications of this fracture. Time to treatment is one of the most important predictors of this outcome with no clear consensus in the literature. The aim of this study was to determine whether early treatment (< 24 hours) of pediatric femoral neck fractures is associated with a lower rate of osteonecrosis of the femoral head compared to late treatment (> 24 hours).
Methods: We searched several databases (PubMed, Embase, and Cochrane library), from January 1966 to November 2017 for any comparative studies that evaluated early (< 24 hours) versus late (> 24 hours) treatment of paediatric femoral neck fractures. We pooled the effect sizes using fixed effects model that compared the rate of osteonecrosis of the femoral head between children undergoing early versus late treatment, open versus closed reduction, displaced versus non-displaced and different Delbet type femoral neck fractures. Descriptive and qualitative data was also extracted.
Results: Of the 391 articles identified, six studies (prospective and retrospective cohort studies) were eligible for the meta-analysis, with a total of 231 paediatric femoral neck fractures. The pooled odds ratio (OR) for osteonecrosis of the femoral head did not show any statistically significant difference between early (< 24 hours) versus late (> 24 hours) treatment (OR = 1.19, 95% CI 0.56, 2.51, I2 = 23.6%), nor between open versus closed reduction of paediatric femoral neck fractures (OR = 1.62, 95% CI 0.82, 3.22, I2 = 19.57%). Displaced and Delbet type I/II femoral neck fractures were 3.8 (OR = 3.81, 95% CI 1.49, 9.78, I2 = 0.00%) and 2.4 (OR = 2.43, 95% CI 1.28, 4.61, I2 = 0.57%) times more associated with osteonecrosis of the femoral head compared to non-displaced and Delbet type III/IV fractures respectively.
Conclusions: The cumulative evidence at present does not indicate an association between the time to treatment or method of reduction of femoral neck fractures in children and the risk of osteonecrosis of the femoral head. However, initial expedient treatment of femoral neck fractures in children should always remain the rule especially for displaced and Delbet type I/II femoral neck fractures.
Level of evidence: II/III.
Keywords: Avascular necrosis; Femur neck fractures; Hip fractures; Meta-anlysis; Osteonecrosis; Pediatrics.