Femoral Neck Length and Hip Fracture Risk

Abstract

To determine whether there are differences in femoral skeletal geometry in fracture-prone subjects when size, positioning diagnosis, and age are controlled, we compared femoral measurements made from the uninvolved hip on 119 plane anteroposterior pelvis radiographs of women without fracture to those of the contralateral hip in a group of 43 female patients with hip fractures (neck, 23; intertrochanteric, 20). The hip was imaged in a standardized position of rotation and adduction. Race, age, and musculoskeletal diagnosis were known. Subjects were grouped by diagnosis of the opposite hip condition (rheumatoid arthritis, osteoarthritis, and normal) and compared. Measurements were also analyzed as ratios to head diameter (HD), neck diameter (ND), and pelvic width. Femoral neck length (NL) was measured from skeletal preparations and imaged in controlled positions of abduction and external rotation. No differences were found between the neck and intertrochanteric fracture groups. The differences between the fracture group and the controls were a thinner femoral cortex (measured at a point one head radius below the lesser trochanter) a larger femoral head, and a larger femoral ND in the fracture group (p < 0.025). The difference in cortical thickness was still significant when scaled by size, but the ratio of HD to ND was equivalent in fractures and controls. No difference in femoral NL could be demonstrated. The experimental measurements showed that apparent NL is significantly position sensitive and this may explain previously reported differences in fracture

Analysis of hip geometry by clinical CT for the assessment of hip fracture risk in elderly Japanese women

“…It is difficult to maintain a good positioning of the hip joint so as to be able to analyze the geometry using such techniques as HAL and NSA in the radiographs and DXA after hip fracture, since the legs are usually abducted and outwardly rotated 18) . If the measurement is performed after an operation, the parameters are influenced by the effect of limb disuse.…”

Method for Cortical Bone Structural Analysis From Magnetic Resonance Images1

“…Recent data suggest that weakened cortical bone may primarily be responsible for hip intracapsular hip fracture (6), thus emphasizing the importance for quantitatively assessing and monitoring cortical structure. Support for the role of cortical bone architecture as a risk factor for hip fracture is found in several studies of postmenpausal osteoporosis, where strong associations have been reported between proximal femur geometry and fracture incidence (7)(8)(9). Additionally, bone mineral density (BMD) supplemented by femoral geometry has been shown to be more predictive of breaking strength than BMD alone (10).…”

Proximal hip geometry is linked to several chromosomal regions: Genome-wide linkage results from the Framingham Osteoporosis Study

“…Thus, proximal femora of elderly men and women with any type of osteoporotic fracture have lower estimated bending strength and axial strength, thinner cortices and wider subperiosteal diameters than femora of fracturefree counterparts [8]. Compared to those without fractures, women with hip fractures (as well as their daughters [8,9]) have altered femoral geometry, including wider femoral necks and longer hip axis lengths, independently of femoral neck BMD, age, and body size [10][11][12][13][14][15][16]. Currently, femoral geometry is assessed non-invasively by radiogrammetry and/or DXA-based hip structural analysis (HSA), as well as by 3D methods like computed tomography.…”