Comparison of the trabecular development within the juvenile human distal tibia and talus

There is an increasing understanding of ontogenetic changes in trabecular bone, nevertheless, gaps in our knowledge remain. By comparing two anatomically different bones that share similar locomotive demands, we aim to investigate how developmental and biomechanical factors interact. We hypothesise that the talus and distal tibia will share a developmental trajectory until the acquisition of the bipedal gait, after which the trabecular architecture will diverge to adapt to forces.

Thirty-three pairs of articulating distal tibia and tali from the Scheuer Collection, ranging from 28 intrauterine weeks to 8 postnatal years, were microcomputed tomography scanned. Scaled volumes of interest (VOIs) were placed within the distal tibia and talus. Within each VOI, anisotropy, bone volume fraction, trabecular thickness, trabecular separation, trabecular number, and structural model index were quantified. Mann Whitney-U tests and Independent T-tests were used to compare trabecular parameters between the distal tibia and talus. Additionally, bone volume fraction and anisotropy vector fields were mapped.

Our hypothesis was rejected. All trabecular parameters, except anisotropy, share a developmental trajectory within the distal tibia and talus. Tibial anisotropy was statistically significantly higher than talus anisotropy. Prior to the onset of the bipedal gait, it is postulated the talus is more isotropic due to differences in ossification patterns. Once the bipedal gait has developed, the transmission of weight-bearing forces likely results in the differences in anisotropy.

Overall, this research provides insight into how different trabecular parameters respond to developmental and biomechanical factors during development, adding to our growing knowledge of trabecular ontogeny.