245 - Caregiver reported femur fracture injury mechanisms and identified fracture morphologies among young children

Publication Number: 2236.245

Stephanie M. Ruest, Hasbro Children's Hospital at Rhode Island Hospital, Foxboro, MA, United States; Emely Arenas Lemus, Hasbro Children's Hospital at Rhode Island Hospital, Westport, MA, United States; William Rudman, The University of Texas at Austin, Austin, TX, United States; Amy P. Goldberg, The Warren Alpert Medical School of Brown University, Providence, RI, United States; Susan Duffy, Hasbro Children's Hospital at Rhode Island Hospital, Brown University, Providence, RI, United States

Background: Current literature on the epidemiology of femur fractures among young children in the context of the caregiver reported trauma mechanism and subsequently identified fracture morphology is lacking. We aim to characterize the caregiver-provided injury mechanisms and associated femur fracture morphologies among children ≤5 years.

Objective: We aim to characterize the caregiver-provided injury mechanisms and associated femur fracture morphologies among children ≤5 years.

Design/Methods: This is a sub-analysis of a retrospective study of 4,285 children ≤5 years with fractures in a pediatric emergency department from March 2015-April 2023. Acute femur fracture encounters were identified by ICD9/10 codes and confirmed by chart review. We abstracted demographics, caregiver-reported injury mechanisms, and fracture morphologies. Descriptive statistics are reported.

Results: We identified 185 encounters for acute femur fractures, with a mean patient age of 28.8 months (SD 19.2). 9.7% of encounters were children < 6 months (N=18), 16.2% 6- < 12 months (N=30), 5.4% 12- < 18 months (N=10), 16.2% 18- < 24 months (N=18), 27.6% 24- < 36 months (N=51), and 31.4% ≥36 months (N=58). Distinct differences in reported mechanisms and fracture morphologies by age group were identified. Among infants < 6 months, 33.3% (N=6) had no trauma history and 27.8% (N=5) were dropped by a caregiver. Among infants 6- < 12 months (N=18), 56.7% fell from elevated surfaces. There was no predominant mechanism among children 12- < 18 months. Among children ≥18 months, 40.2% (N=51) fell from standing/running and 25.2% (N=32) fell from elevated surfaces. Encounters without reported trauma (N=11) were associated with an equal distribution of transverse and spiral/oblique morphologies. Among all falls from elevated surfaces (N=52), nearly 60% of fractures were spiral/oblique and 23.1% were transverse. Of the 51 falls from standing/running, 90.2% were associated with spiral/oblique fractures.

Conclusion(s): Reported mechanisms and femur fracture morphologies vary substantially between non-mobile infants and ambulatory children. One third of non-mobile infants had no trauma history and fracture morphologies that require significant force, which should raise concern for abuse. Changing fracture morphologies across age groups appear to coincide with evolving developmental capabilities and associated reported injury mechanisms. This is the first study to demonstrate substantial differences in reported mechanisms and associated fracture morphologies within this population and may inform risk stratification for potential abusive versus accidental femur fractures.

Figure 1. Proportions of caregiver reported mechanisms, by age group
Elevated surface includes: bed, changing table, counter, couch, high chair, etc. Other mechanism includes: birth trauma, direct blow/strike, motor vehicle crash, pedestrian struck, "other" not otherwise specified.

Figure 2. Proportions of fracture morphologies, by age group
Other fracture type includes: impacted, greenstick, buckle/torus, periosteal new bone formation, Salter Harris 2 or 3 metaphyseal fracture, other not specified.

Figure 3. Proportions of fracture morphologies, by caregiver reported mechanism
Elevated surface includes: bed, changing table, counter, couch, high chair, etc. Other mechanism includes: birth trauma, fall down stairs alone, fall down stairs while held by caregiver, direct blow/strike, motor vehicle crash, pedestrian struck, "other" not otherwise specified. Other fracture type includes: impacted, greenstick, buckle/torus, periosteal new bone formation, Salter Harris 2 or 3 metaphyseal fracture, other not specified.