Purpose or Case Report: Fractures are a common manifestation of physical child abuse, and when present can have considerable bearing on the legal process. Although the timing of skeletal injury and healing is of great importance in forensic cases, the dating of fractures in the age group in which fractures from physical abuse most frequently occur is largely based on the radiologist’s personal experience as opposed to primary research. A full understanding of the radiological features of healing in infant fractures will enhance the assessment of fracture dating in cases where the time of injury is unknown, such as suspected abuse. The objective of this study was to describe the timing of fracture healing in infants using previously defined radiographic signs of fracture healing.
Methods & Materials: We completed a retrospective cross-sectional time-series study of long bone fractures in infants from 2006 -2013. After exclusion criteria were applied a total of 100 digital images were available for review from 51 infants. Utilizing published criteria for dating fractures, the presence or absence of four pre-defined features of healing were scored: periosteal reaction, callus, bridging, and remodeling. Three radiologists independently scored radiographs with a 3 point scale, marking each feature as present, absent, or equivocal. Statistical analysis using free marginal kappa was conducted.
Results: The level of agreement between the three radiologists was high (0.77-0.95) reinforcing the validity of the observations. Features of healing were first seen at 7, 9, 15, and 51 days for periosteal reaction, callus, bridging, and remodeling respectively. The peak periods, defined as ‘data tabulated to identify the earliest agreed recording, peak prevalence intervals (present in >40% of images), and last agreed recording of each feature, were as follows: periosteal reaction 7-130 days, callus 9-26 days, bridging 15-67 days, and remodeling 51-130 days (Fig. 1).
Conclusions: Features of fracture healing develop in a logical progression with periosteal reaction developing first, followed by callus formation, then bridging callus, and finally remodeling. This study builds on prior research in this area, and provides additional supportive evidence when determining whether a given fracture is consistent with a proposed time frame, especially in assessing cases in which non-accidental trauma is a consideration.