Femoral fractures and abuse in children under 36 months old: a Swiss case series.

Abuse should be suspected in infant femoral fractures without significant trauma, especially if the child is non-ambulatory. Review the epidemiological and radiological characteristics of femoral fractures in children under 36 months old to identify those potentially related to child abuse. Cases involving 102 patients presenting with 103 femoral fractures between January 1990 and December 2020 were investigated, paying close attention to mechanisms of injury, fracture patterns, and their possible relations to child abuse. The annual incidence of femoral fractures in patients under 36 months old was estimated at 24.6 per 100 000; the incidence in infants under 13 months was significantly higher than among children between 13 and 36 months old. Most infants under 13 months suffered from transverse or oblique metaphyseal/diaphyseal fractures (93.2%), whereas 67.8% of older children presented with spiral shaft fractures. Data confirmed child abuse in 4.9% of all patients (one with bilateral fractures); femoral fractures were incompatible with their reported mechanisms of injury in 31 patients (30.4%), whereas 12 fractures (11.8%) occurred in unexplained circumstances. More than 50% of femoral fractures occurred with low-energy trauma. The difference in patterns according to patients' ages suggested different mechanisms of trauma in ambulatory and non-ambulatory infants. Confirmed abuses and unclear or inconsistent mechanisms of trauma, raised potential total child abuse cases to 47.1% of our cohort. Level of evidence: Level IV.