Use of a Template-Matching Clavicle Fracture Atlas for Surrogate Dating of Humeral and Femoral Fractures in Young Infants: A Six-Reader Study.

Abstract

BACKGROUND. Fracture dating is important in suspected infant abuse. Birth-related clavicle fractures are common and may provide surrogates to aid long bone fracture dating in infants. OBJECTIVE. The purpose of this study was to assess the impact of a template-matching clavicle fracture timeline atlas on radiologists' performance in dating birth-related fractures of the clavicle, humerus, and femur in young infants. METHODS. This retrospective study included infants 90 days old or younger who underwent radiography of a birth-related clavicle fracture from April 1, 2021, to July 31, 2024 or a birth-related fracture of the humerus or femur from December 1, 2011, to July 31, 2024. All eligible radiographs of each fracture were identified, representing distinct observations for the purposes of analysis. Patient age (expressed as days) at the time of radiograph acquisition served as the reference standard for fracture ages. A nonrigid image registration technique was applied to a nonoverlapping preassembled database of radiographs of birth-related clavicle fracture, to create a fracture dating atlas. Six readers (three trainees and three pediatric radiologists) independently reviewed the radiographs in separate sessions without and with use of the atlas to estimate fracture ages. Interreader agreement was assessed using intraclass correlation coefficients (ICCs). Fracture aging performance was assessed using mean absolute errors (MAEs). RESULTS. The analysis included 145 infants (87 male and 58 female infants) with 269 fracture radiographs (104 of the clavicle, 128 of the humerus, and 37 of the femur). The mean fracture age was 26 ± 19 [SD], 22 ± 14, and 21 ± 13 days for clavicle, humerus, and femur fractures, respectively. Interreader agreement for estimating fracture ages improved from moderate (ICC = 0.69) without use of the atlas to excellent (ICC = 0.91) with use of the atlas. The MAE in fracture dating was significantly lower (p < .05) with than without use of the atlas for all six readers for clavicle fractures (range, 4.8-5.5 vs 5.8-10.1 days), for all six readers for humeral fractures (range, 6.0-12.1 vs 3.0-3.8 days), and for five of six readers for femur fractures (range, 7.4-17.2 vs 3.3-4.8 days). MAE without and with use of the atlas was 8.8 versus 4.3 days, respectively, across trainee readers and 8.4 versus 4.0 days, respectively, across attending physician readers. CONCLUSION. The fracture dating atlas yielded significant improvements in radiologists' performance for dating infant clavicle, humerus, and femur fractures. CLINICAL IMPACT. Clavicle fracture healing patterns can serve as surrogates for dating long bone fractures commonly encountered in infant abuse.