FEMORAL NECK BONE STRESS INJURIES IN CHILDREN AND ADOLESCENTS: A LITERATURE REVIEW AND META-ANALYSIS

Abstract

Background:Most bone stress injuries (BSI) affect weight-bearing bones of the lower extremity. While femoral neck BSIs (FNBSI) are less common, they occur in the pediatric and adolescent population, accounting for 0.7%-21.1% of all sports-related injuries. A recent publication showed a 4-fold increase in the incidence of pediatric BSI. Literature detailing FNBSI in the pediatric population is limited to small case studies. Recommendations are lacking for imaging protocols and grading of injury.Purpose:To assess available evidence-based literature for pediatric and adolescent FNBSI in order to better understand the incidence, risk factors, work up and treatment practices of pediatric and adolescent FNBSI.Methods:A systematic review was conducted to find FNBSI studies in the pediatric and adolescent population. Due to a paucity of literature, information was gleaned from adult FNBSI literature, other areas of BSI in pediatric patients and biomedical papers looking at pediatric growth and bone health. Papers discussing potential risk factors to bone health and pediatric, adolescent and collegiate athletes at higher risk for BSI were also included. Regarding meta-analysis: Search terms included “Femoral Neck,” “Bone Stress Injury; Hip,” “Stress Fracture,” “Stress Fracture + Adolescent.” For the meta-analysis, patients under 20 years of age were reviewed and available information documented. Patients were excluded if they had a known metabolic or chronic medical condition that could be the primary reason or main contributor to their BSI.Results:A total of 66 fractures (57 patients) were identified, 9 bilateral, ranging from 5-19 years. All but 9 (86%) had compression sided fractures; 4/9 tension sided fractures were displaced. 35% (23/66) occurred in military and 30% (20/66) were athletes. Radiographs were most often initial imaging; 22/55 (40%) of those were abnormal, 4 inconclusive. If initial radiographs were negative (or none obtained), 14/33 had repeat positive x-rays, 15/33 positive BS, 12/33 positive MRI. MRI frequently was used to confirm positive radiographs. 6/57 (11%) patients treated conservatively would go on to require surgical fixation.Conclusions:FNBSI is a diagnosis that must be considered in the young, especially when the chief complaint is hip, thigh or groin pain. Radiographs should be the initial diagnostic test, but further imaging is usually necessary to establish the diagnosis and determine a treatment plan. Understanding the specific risk factors to this population is crucial. Further studies in this population are needed to develop a pediatric specific understanding of FNBSI, formulate a proper workup and develop a treatment plan.