Trabecular Plate Loss and Deteriorating Elastic Modulus of Femoral Trabecular Bone in Intertrochanteric Hip Fractures

Abstract

Osteoporotic hip fracture is associated with significant trabecular bone loss, which is typically characterized as low bone density by dual-energy X-ray absorptiometry (DXA) and altered microstructure by micro-computed tomography (µCT). Emerging morphological analysis techniques, e.g. individual trabecula segmentation (ITS), can provide additional insights into changes in plate-like and rod-like trabeculae, two major microstructural types serving different roles in determining bone strength. Using ITS, we evaluated trabecular microstructure of intertrochanteric bone cores obtained from 23 patients undergoing hip replacement surgery for intertrochanteric fracture and 22 cadaveric controls. Micro-finite element (µFE) analyses were performed to further understand how the abnormalities seen by ITS might translate into effects on bone strength. ITS analyses revealed that, near fracture site, plate-like trabeculae were seriously depleted in fracture patients, but trabecular rod volume was maintained. Besides, decreased plate area and rod length were observed in fracture patients. Fracture patients also showed decreased elastic moduli and shear moduli of trabecular bone. These results provided evidence that in intertrochanteric hip fracture, preferential loss of plate-like trabeculae led to more rod-like microstructure and deteriorated mechanical competence adjacent to the fracture site, which increased our understanding of the biomechanical pathogenesis of hip fracture in osteoporosis.

The Influence of High-Impact Exercise on Cortical and Trabecular Bone Mineral Content and 3D Distribution Across the Proximal Femur in Older Men: A Randomized Controlled Unilateral Intervention

“…(39) Increased trabecular density was also evident at the inferior aspect of the femoral head, whose trabecular density contributed most strongly to hip fracture discrimination in vivo. (40) Most studies regarding hip fracture risk have focused on cortical bone in the femoral neck subregions, but recent evidence has shown that trabecular bone loss in hip fracture patients occurred not only at the femoral neck but also expanded to the intertrochanteric region, (41,42) which is a region of the proximal femur that is rich in trabecular bone. We detected substantial changes in endocortical trabecular density in the lateral trochanteric region (between 10% and 13%) with exercise, but little change in cortical mass surface density at this site.…”

Trabecular plates and rods determine elastic modulus and yield strength of human trabecular bone

“…It has been demonstrated that there is an apparent transition from plate-like to rod-like microarchitecture in osteoporotic trabecular bone by either the Structure Model Index (SMI) or more advanced ITS based measures [10, 32, 33]. From both computational and experimental studies, it has been shown that trabecular plates play a more dominant role in mechanical integrity of human trabecular bone [17, 34, 35]. It is not clear how adequate is the plate-rod assumption of trabecular bone microarchitecture in quantifying mechanical properties of human trabecular bone.…”

Deterioration of trabecular plate-rod and cortical microarchitecture and reduced bone stiffness at distal radius and tibia in postmenopausal women with vertebral fractures

“…(23–26) Because trabecular plates and rods of various orientations have different roles in determining mechanical properties of trabecular bone, ITS assessment of trabecular microarchitecture adds a unique perspective to bone fragility. (27–32) Studies using ITS have shown postmenopausal women with a history of fragility fractures have significantly lower trabecular plate volume, number and connectivity, regardless of aBMD by DXA, suggesting that trabecular plate microarchitectural abnormalities may increase the risk for osteoporotic fractures, over and above that associated with low BMD by DXA. (8,32,33) However, no studies have focused exclusively on vertebral fracture patients.…”

“…(27–32) Studies using ITS have shown postmenopausal women with a history of fragility fractures have significantly lower trabecular plate volume, number and connectivity, regardless of aBMD by DXA, suggesting that trabecular plate microarchitectural abnormalities may increase the risk for osteoporotic fractures, over and above that associated with low BMD by DXA. (8,32,33) However, no studies have focused exclusively on vertebral fracture patients.…”