Postmortem assessment of fetal diaphyseal femoral length: Validation of a radiographic methodology

Depending on the general condition of fetal remains, forensic specialists m ight face difficulties concerning age estimation. Reference tables and regr ession equations are helpful devices in this task, although they are genera lly applied for complete fetuses or fetal remains including soft tissues. H owever, the problem of age estimation stays for osseous remains, both for e ntire bones and ossified parts, since most of the reference tables come fro m ultrasonographic measurements, which are not easily reproducible on fetal osseous remains. Furthermore, the ultrasonographic measurements contain sl ight errors in comparison to the real anatomical ones. This study describes a radiographic protocol and a measurement technique that facilitate and im prove bone measurements, and therefore, Facilitate age estimation, too. A q ualitative criterion, namely a clear-cut bony endplate, was defined and tes ted. Its reliability (repeatability and reproducibility) turned out to be g ood, showing nonsignificative differences to the threshold of 0.05, with av erage errors of 0.26 and 0.44 mm respectively. Moreover, concerning the tes t of eventual size differences between the right and left femurs showed a P value < 0.0001. The test of the qualitative criterion was based on the com parison of the radiographic in situ femur measurements and the radiographic measurements of the same bones after dissection. The results were satisfac tory, since an aver age error of 0.58 mm was obtained, which did not give a ny significant differences to the threshold of 0.05. It was concluded that this methodology provides an easy and precise new measurement tool for fore nsic practice, and can allow us to establish some nonultrasonographic table s, which fit our population.