Microvasculature and Trabecular Bone in Beagle Proximal Femur: Microstructural Insights

Avascular necrosis of femoral head and malunion are frequent post-operative complications of femoral neck fractures. To optimize surgical techniques, this study aims to provide a microstructural understanding of intraosseous microvasculature and the trabecular bone of the femoral head and neck. This anatomical study analyzed twenty-eight femora from fourteen cadaveric beagles. Common iliac arteries were infused with colored silicone-resin for vascular visualization, followed by non-decalcified hard tissue processing using the EXAKT®, and Masson's trichrome staining. Morphology and histomorphometric analysis were performed by Nikon NIS Elements BR and ImageJ-fiji. Histomorphometry revealed thin, elongated trabeculae with high vascularity aligned parallel in the neck; numerous intraosseous anastomoses at the neck-shaft and head-neck junctions; thick trabeculae with smaller marrow cavities and dense, branching vascular networks near the cortex in the head. Quantitative analysis showed an inverse correlation between trabecular density and mean vascular density/vascular length density, with no significant sex or side differences. Dense connective tissue fibers maintained the microvasculature and trabeculae structure. The femoral neck displayed an outside-in microvascular pattern via retinacular branches. Conversely, the femoral head had an inside-out pattern through epiphyseal branches reinforced by medullary branches. Dense intraosseous microvasculature aligned sub-cortically. The study identified a potential anatomical safe zone for screwing in femoral neck fractures in beagles. These findings provide an anatomical basis for translational research in joint preservation techniques for humans. [Display omitted] •The neck exhibits thin, elongated trabeculae, high vascularity.•There are numerous intraosseous anastomoses at neck-shaft and head-neck junctions.•The head contains thick trabeculae, dense vascular networks near cortex.•An Inverse correlation is observed between trabecular and vascular density, with no differences based on gender or side.•A potential safe zone for screw placement in femoral neck fractures has been identified.