Trabecular inner morphology of post-cranial bone fractures of known post-traumatic ages: can 3D measurements through micro-CT be useful for dating?

The accurate dating of bone fractures in forensic casework is crucial since it can assist in testing witness statements and contribute to understanding the chronology of events prior to death in cases of violent death, abuse, maltreatment and torture. The estimation of the post-traumatic survival time (PTST) is based on the tissue healing response after traumatic tissue damage and to date, in case of bone injuries, it remains a tricky issue in the forensic field, especially when dealing with dry bones. New high-resolution imaging, and in particular microcomputed tomography (micro-CT), has the potential to significantly improve our abilities to interpret antemortem and perimortem lesions in a less destructive analysis. The present experimental pilot study is aimed at evaluating the applicability of micro-CT on dry bones to find useful parameters able to describe the trabecular microarchitecture for objective fracture dating. With this intent, four regions of interest (two located in the callus and two in areas more distant to it – referred to as healthy bone) were selected by visual inspection from each of the nine costal fractures of known post-traumatic ages constituting the study sample. The 3D measurements of the trabecular inner morphology of the bone samples were performed on the four selected areas of interest using the five histomorphometric parameters most commonly used for the study of the 3D bone trabecular microarchitecture with micro-CT, including anisotropy, connectivity, BV/TV fraction [%] (bone volume fraction), trabecular thickness [mm] (TbTh) and trabecular separation [mm] (TbSp). As a result, the quantitative preliminary micro-CT measurements of the 3D trabecular microstructure of bone calluses obtained from this study demonstrate the existence of trends for some parameters of the trabecular microstructure relative to the age of the callus, including the degree of anisotropy, connectivity and trabecular spacing. The results obtained are consistent with the healing process of bone and in line with the current literature and could represent useful features for the construction of objective and quantitative models for fracture dating.