Insights From the Trabecular Development of the Juvenile Human Distal Tibia and Talus

It is postulated that early trabecular form is under genetic control whilst skeletal loading drives changes in the post-natal skeleton. However, it remains unclear how factors such as vascularisation and ossification patterns influence the development of trabecular bone. By comparing two anatomically different bones that share similar locomotive demands, this study aims to investigate how developmental and biomechanical factors interact. Forty-one tali and 69 distal tibiae 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, degree of anisotropy (DA), bone volume fraction (BV/TV), and trabecular thickness, trabecular separation, and trabecular number were quantified. VOIs were compared using Kruskal-Wallis H tests to assess trabecular heterogeneity at different stages of development. Mann Whitney-U tests and Independent T-tests were used to compare trabecular parameters between pairs of articulating distal tibia and talus. Additionally, bone volume fraction and anisotropy vector fields were mapped. All trabecular parameters, except DA, shared a developmental trajectory within the distal tibia and talus. Both bones exhibit rapid accumulation of bone mass during the fetal period, followed by a reduction in BV/TV during the first year of life. Structural heterogeneity then increases as each bone adapts to the acquisition and maturation of the bipedal gait. Prior to the onset of the bipedal gait, it is postulated the talus is more isotropic than the tibia due to differences in ossification and vascular patterns. Once the bipedal gait has developed, the transmission of weight-bearing forces likely results in differences in DA. Overall, this research provides insight into how trabecular bone responds to developmental and biomechanical factors during the early stages of life