Postmortem Assessment of Fetal Diaphyseal Femoral Length: Validation of a Radiographic Methodology

Abstract

Depending on the general condition of fetal remains, forensic specialists might face difficulties concerning age estimation. Reference tables and regression equations are helpful devices in this task, although they are generally applied for complete fetuses or fetal remains including soft tissues. However, the problem of age estimation stays for osseous remains, both for entire bones and ossified parts, since most of the reference tables come from ultrasonographic measurements, which are not easily reproducible on fetal osseous remains. Furthermore, the ultrasonographic measurements contain slight errors in comparison to the real anatomical ones. This study describes a radiographic protocol and a measurement technique that facilitate and improve bone measurements, and therefore, facilitate age estimation, too. A qualitative criterion, namely a clear-cut bony endplate, was defined and tested. Its reliability (repeatability and reproducibility) turned out to be good, showing nonsignificative differences to the threshold of 0.05, with average errors of 0.26 and 0.44 mm respectively. Moreover, concerning the test 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 comparison of the radiographic in situ femur measurements and the radiographic measurements of the same bones after dissection. The results were satisfactory, since an average error of 0.58 mm was obtained, which did not give any significant differences to the threshold of 0.05. It was concluded that this methodology provides an easy and precise new measurement tool for forensic practice, and can allow us to establish some nonultrasonographic tables, which fit our population.

Radiographic fetal osteometry: Approach on age estimation for the portuguese population

“…The decision of employing XR measurements was due to the fact that they are more reliable than ultrasound measurements and can easily be used when the subject of study (in forensic context, for instance) retains soft tissues [4,17,18]. This was a retrospective cohort study.…”

“…Yet, the lack of large identified skeletal collections including fetuses precludes the existence of appropriate formulae [8]. Consequently, these tables are mostly based on ultrasonographic measurements [9][10][11][12] that might differ from actual measurements on dry bone [17,18]. Moreover, formulae applicable on dry bones have twosteps and are mostly supported by outdated literature [8,13].…”

“…The need to develop new standards and to evaluate their specificity in relation to the population on the basis of which they were developed has become obvious. Recent studies, as is the case of Adalian et al [4,17], who validated a methodology using measurements made on radiographies, which are more reliable than ultrasound measurements, used an identified sample, obtained from a hospital database. As such, the main goal of the present study was to update fetal radiographic data for the Portuguese population, using a validated method [17].…”

“…Recent studies, as is the case of Adalian et al [4,17], who validated a methodology using measurements made on radiographies, which are more reliable than ultrasound measurements, used an identified sample, obtained from a hospital database. As such, the main goal of the present study was to update fetal radiographic data for the Portuguese population, using a validated method [17]. The authors also sought to identify which of the three studied bones (femur, tibia and humerus) was more accurate to estimate gestational age.…”

“…Also, it was intended to assemble reference tables for each bone to simplify gestational age comparisons. The final purpose of this study was to compare the obtained equation for the femur with the formulas developed by other authors with the same aim, namely those from Fazekas and Kosa, Adalian et al and Scheuer and Black [8,17,19].…”