Comparison of Femoral Neck Stress Fractures in Pediatric versus Young Adult Athletes

Abstract

Objectives:To compare the demographics, metabolic bone health, radiologic features, treatment approaches and recurrence rates of pediatric versus young adult athletes with femoral neck stress fractures.Methods:A retrospective review was performed on all patients <45 years-old who were diagnosed with a femoral neck stress fracture at a single tertiary-care referral center from 2003-2015. Patients who had undergone previous hip surgery or had primary bone disorders/lesions were excluded. Variables analyzed included demographics, presenting symptoms, metabolic bone health (laboratory results, Dexa scores, menstrual history, eating disorder history), imaging, treatment approach and clinical course.Results:Forty-nine patients (mean age 21.4 years, range 5-44, 78% females) met study inclusion criteria, including 28 pediatric patients (mean age 14.4 years, range 5-19 years, 71% females) and 21 young adults (mean age 30.8 years, range 20-44 years, 86% females). A higher percentage of females was seen with each increasing decade of age, with 50% of pediatric patients under 11 years-old being male. Mean BMI was lower (p=0.04) in the pediatric group (20.6 kg/m2 +/-3.42) than the adult group (21.8 kg/m2 +/-2.04). Pain was the presenting complaint in all patients, with pain localized to the groin in 80% of cases. Participation in running sports was higher for the young adult cohort (86%) than the pediatric cohort (50%), while multiple sports were played more by pediatric patients (29%) than young adults (5%). History of previous acute fractures (2%) and previous stress fractures (14%) was identical between groups. Delayed menarche was recorded in 6% of pediatric patients, and menstrual irregularity was reported in 29% and 33% of pediatric and adult females, respectively. The base of the femoral neck was most common location for fracture in both pediatric (67%) and adult (81%) groups, while transcervical fractures were more likely to occur in pediatric (29%) than adult patients (6%). More significant treatment interventions were pursued in the pediatric group (spica casting: n=2, operative screw fixation, n=4) than the adult group, all of whom demonstrated healing with activity modification, with varying degrees of weight bearing protection and medical optimization of metabolic bone health. There was no difference in the mean time to healing (13.3 weeks), or in the mean time to return to sports (Peds: 16wks, Adults: 13wks) between groups. There was a significant correlation between time to RTS and the extent of the femoral neck edema (p=0.048).Conclusion:Pediatric caregivers should be aware of femoral neck stress fractures in young athletes, an entity historically described almost exclusively in adults. Stress fractures in pediatric and adolescent patients are more likely to occur higher on the neck than adult patients, and both sexes in children may be affected to a greater degree than in adult counterparts, in whom females are affected much more commonly. Groin pain and participation in running sports are common in both groups, while multi-sport pediatric athlete patients may be more likely to be affected than in the adult population. More significant treatment interventions may be warranted in children. To avoid the catastrophic sequella of a displaced femoral neck fracture, proactive diagnostic workup and consideration of interventions such as spica casting or surgical screw fixation should be exercised given concerns related to non-compliance in this population.