Novel Formulae for Estimating Weight in Children Using Epiphyseal and Metaphyseal Breadths and Torsional Rigidity (J) Values of the Femur and Tibia Derived from a Modern New Mexico Sample

Background/Objective: Most weight estimation formulae developed for children from skeletal measurements are based on 20 individuals from the Denver Growth Study. This limitation is mainly due to the availability of data. The formulae produced using these data are limited to a small range of variation in weight, which may result in reduced applicability. This study develops new weight estimation formulae relying on a larger and more diverse sample of deceased children (n = 77) of known age and weight from the New Mexico Decedent Image Database. Methods: A classical calibration regression approach was used to generate weight estimation equations from virtual metaphyseal breadths, epiphyseal breadths, and torsional rigidity (J) of the femur and tibia. Equations were developed separately for the two sexes, two BMI categories, and three age categories. Results: Midshaft femoral J values (45.5% of the total diaphyseal length) and proximal tibial J values (75% of the total diaphyseal length) correlate most highly with body weight and when used to develop weight estimation formulae produce the least amount of error. In general, the breadth measures were less correlated and had larger error than the J values, though the distal femoral metaphyseal breadth produced the highest coefficients of determination and lowest error of the breadth formulae. Conclusions: While these formulae are based on a sample of modern children, the variation that they encompass and the different equations provided allow users to apply them in a variety of circumstances. However, weight estimation may have limited value due to large prediction errors.