Peter Zioupos

Background: Stature estimation is a key parameter in biological profiling of human skeletal remains and thus in aiding in the identification process of the deceased. Various methods, including anatomical approaches, multifactorial regressions and organic correlation approaches, have been developed to estimate stature. Challenges arise from incomplete or altered remains, outdated reference samples, and the lack of population specific studies. This paper critically examines genetic influences and population-specific factors, the present status quo, recent developments and the challenges in stature estimation in forensic anthropology. Methods: The study appraises the current status, challenges, and future directions of stature estimation in forensic anthropology and bioarchaeology. The open-source literature is systematically identified, and relevant osteological and imaging-based studies are screened and prioritised when they report original empirical data or clearly defined methodological developments, enabling consistent extraction of sample and population descriptors, modelling strategies, and limitations. Included studies are then synthesised comparatively and summarised in a study table to support direct cross-study evaluation. Results: Stature estimation accuracy is shown to depend on population, ancestry, sex, time period, and environment, with cross-population or cross-temporal equation transfer identified as a key source of bias. Limitations include fragmented/altered remains and non-representative reference samples, while newer imaging and probabilistic approaches improve performance when supported by suitable data and explicit error quantification. Conclusions: In the present article, stature estimation is positioned as a context-dependent, evidence-weighted process rather than a fixed calculation.

Computed tomography and magnetic resonance imaging are two powerful modalities which can be used in the clinical setting to produce data for the creation of patient-specific finite element analysis (FEA) models and physical analogues—for instance, by using additive manufacturing (AM)—that mimic the properties of soft and hard tissues, both morphologically and mechanically. However, there remains a gap between creating a perfect biofidelic physical analogue and its computational counterpart. This gap exists because, firstly, in silico models are often too complex to realise, and secondly, real-life conditions are challenging to emulate both computationally and mechanically, as they involve multiscale situations that are inherently heterogeneous and patient specific. In this study, we applied a multi-scale approach to design and model porcine vertebral specimens. Our results identified critical design factors that affect the quality and accuracy of the models, specifically highlighting that scanning resolution/fidelity and the thresholding technique have a directly proportional impact on model accuracy. A small shift up and down the greyscale level by 20 units can affect the behaviour of the AM sample by as much as [−15% +47%]. Working up the levels for manufacturing, testing and modelling (i) cylindrical cores to (ii) whole vertebrae and then (iii) a whole spine motion segment, we observed that the fidelity of predictions reduces, and errors increase as the structure becomes more complicated and intricate (3.6%, 7.5% and 15%, respectively). We are confident that further material-level developments will provide solutions for the more intricate parts of spinal motion segments, such as the intervertebral discs and facets, which in their natural form are highly sophisticated structures. To the best of our knowledge, this is the first time a holistic multiscale approach has been implemented to produce AM biofidelic analogues of skeletal parts. Our data showed good agreement between the physical and in silico models, confirming that it is possible to model real-time objects and situations both physically and in silico. This ultimately will enable the development of accurate, patient-specific physical models for use in biomechanical testing and medicolegal applications.

The current protocol used to determine if an individual is osteoporotic relies on assessment of the individual’s bone mineral density (BMD), which allows clinicians to judge the condition of a patient with respect to their peers. This, in essence, evaluates a person’s fracture risk, because BMD is a good surrogate measure for strength and stiffness. In recent studies, the authors were the first to produce fracture toughness (FT) data from osteoporotic (OP) and osteoarthritic (OA) patients, by using a testing technique which basically analyzes the prerequisite stress conditions for the onset of growth of a major crack through cancellous bone tissue. FT depends mainly on bone quantity (BV/TV, bone volume/tissue volume), but also on bone micro-architecture (mArch), the inner trabecular design of the bone. The working research hypothesis of the present study is that mArch offers added prediction power to BV/TV in determining FT parameters. Consequently, our aim was to investigate the use of predictive models for fracture toughness and also to investigate if there are any significant differences between the models produced from samples loaded across (A_C, transverse to) the main trabecular orientation and along (A_L, in parallel) the trabeculae. In multilinear regression analysis, we found that the strength of the relationships varied for a crack growing in these two orthogonal directions. Adding mArch variables in the Ac direction helped to increase the R² to 0.798. However, in the A_L direction, adding the mArch parameters did not add any predictive power to using BV/TV alone; BV/TV on its own could produce R² = 0.730. The present results also imply that the anisotropic layout of the trabeculae makes it more difficult for a major crack to grow transversely across them. Cancellous bone models and remodels itself in a certain way to resist fracture in a specific direction, and thus, we should be mindful that architectural quality as well as bone quantity are needed to understand the resistance to fracture.

Introduction: Flatfoot is a condition commonly seen in children; however, there is general disagreement over its incidence, characterization and correction. Painful flatfoot accompanied with musculoskeletal and soft tissue problems requires surgery to avoid arthritis in adulthood, the most common surgical approach being two osteotomies to the calcaneus and medial cuneiform bones of the foot. Objectives: This study focuses on the parametrization of these two bones to understand their bone morphology differences in a population sample among 23 normal subjects. Population differences could help in understanding whether bone shape may be an important factor in aiding surgical planning and outcomes. Methods: A total of 45 sets of CT scans of these subjects were used to generate surface meshes of the two bones and converted to be iso-topological meshes, simplifying the application of Generalized Procrustes Analysis and Principal Component Analysis, allowing the main sources of variation between the subjects to be quantified. Results: For the calcaneus, 16 Principal Components (PCs) and, for the medial cuneiform, 12 PCs were sufficient to describe 90% of the dataset variability. The quantitative and qualitative analyses confirm that for the calcaneus PC1 describes the Achilles attachment location and PC2 largely describes the anterior part of the bone. For the medial cuneiform, PC1 describes the medial part of the bone, while PC2 mainly describes the superior part. Conclusion: Most importantly, the PCs did not seem to describe the osteotomy sites for both bones, suggesting low population variability at the bone cutting points. Further studies are needed to evaluate how shape variability impacts surgical outcomes. Future implications could include better surgical planning and may pave the way for complex robotic surgeries to become a reality.

Assessing the timing of skeletal trauma significantly impacts the reconstruction of events surrounding death and deposition in forensic cases. However, there are no absolute time frames in which the characteristics of wet bone (peri-mortem) fractures transition to dry (post-mortem) fractures. The aim of this study was to attempt to identify a point within the post-mortem interval in which the characteristics of bone change from wet to dry bone properties. A total of 32 deer ribs were placed in a laboratory burial environment and a set of three were fractured with blunt force trauma every week during a ten-week period. All samples and the inflicted trauma effects were documented and analysed by macroscopic observation, scanning electron microscope (SEM) analysis, thermal analysis, biomechanical analysis, and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR). No significant difference was found in the macroscopic, microscopic, thermal, and biomechanical analyses of the trauma inflicted over the 10-week period. A significant difference was only found in the carbonate-to-phosphate ratio in analytical chemistry. The results suggest that interpreting wet bone characteristics in forensic anthropology as having been inflicted during the peri-mortem period (around the time of death) should also consider that these, in fact, could be inflicted well after death (post-mortem) as wet bone properties as this study has shown persist at least 10 weeks after death in a burial environment.

Forensic anthropology includes, amongst other applications, the positive identification of unknown human skeletal remains. The first step in this process is an assessment of the biological profile, that is: sex, age, stature and ancestry. In forensic contexts, age estimation is one of the main challenges in the process of identification. Recently established admissibility criteria are driving researchers towards standardisation of methodological procedures. Despite these changes, experience still plays a central role in anthropological examinations. In order to avoid this issue, age estimation procedures (i) must be presented to the scientific community and published in peer reviewed journals, (ii) accurately explained in terms of procedure and (iii) present clear information about the accuracy of the estimation and possible error rates. In order to fulfil all these requirements, a number of methods based on physiological processes which result in biochemical changes in various tissue structures at the molecular level, such as modifications in DNA-methylation and telomere shortening, racemization of proteins and stable isotopes analysis, have been developed. The current work proposes a new systematic approach in age estimation based on tracing physicochemical and mechanical degeneration of the rib cortical bone matrix. This study used autopsy material from 113 rib specimens. A set of 33 parameters were measured by standard bio-mechanical (nanoindentation and microindentation), physical (TGA/DSC, XRD and FTIR) and histomorphometry (porosity-ImageJ) methods. Stepwise regressions were used to create equations that would produce the best ‘estimates of age at death’ vs real age of the cadavers. Five equations were produced; in the best of cases an equation counting 7 parameters had an R² = 0.863 and mean absolute error of 4.64 years. The present method meets all the admissibility criteria previously described. Furthermore, the method is experience-independent and as such can be performed without previous expert knowledge of forensic anthropology and human anatomy.