Hip Fracture Risk and Proximal Femur Geometry from DXA Scans

Abstract

In this retrospective study of hip fracture risk evaluation from hip dual-energy X-ray absorptiometry (DXA) scans, our objectives were to determine which part of the femoral neck length contributes most to the fracture risk and to define a geometric parameter better than hip axis length (HAL) for discriminating hip fracture patients. Forty-nine Caucasian women with a nontraumatic femoral neck fracture were matched on age to 49 normal women and on both age and femoral neck bone mineral density (BMD) to 49 unfractured women. In addition to BMD, geometric parameters including neck-shaft angle, neck width and several HAL segments were evaluated by discriminant analysis to determine which was the best hip fracture discriminator. Neck-shaft angle had a limited influence on the hip fracture risk. Age-related bone loss was associated with a neck width increase in unfractured and fractured patients. HAL was significantly longer in fractured patients and was a significant discriminator between fractured patients and normal controls. HAL was not significant as a discriminator between fractured and low-BMD unfractured patients. The intertrochanter-head center distance (from the intertrochanteric line to the femoral head center) coincides with the femoral lever arm and includes no segments that adapt to BMD changes, such as the greater trochanter-intertrochanter distance. Among all tested lengths, this segment was the part of HAL that discriminated best between fractured and low-BMD unfractured patients. A longer intertrochanter-head center distance increased the risk of femoral neck fracture among low-BMD patients. Including automatic measurement of this segment in standard DXA protocols may prove useful in identifying patients at high risk for hip fracture. At present, HAL remains the easier neck length to measure, but automatic evaluation of the intertrochanter-head center distance must be a goal for future image analysis development.

Femoral neck shaft angle width is associated with hip-fracture risk in males but not independently of femoral neck bone density

“…Nevertheless, it should be pointed out that in males, a statistically significant inverse relationship between the NSA and FN-BMD was found, as already reported by others, 14,18 which was not observed in females. 26,29 The latter finding was also reported by other authors, 9,30 who found NSA to be an independent predictor of hip fracture in females. Therefore, it may be that the negative correlation of FN-BMD with NSA leads BMD to capture some of the effects of NSA on hip fracture; thus explaining, at least partially, the disagreement between males and females regarding the independence of the ability of NSA to predict hip fracture.…”

Evaluation of the Singh index and femur geometry in osteoporotic women

“…It was automated in DXA instruments in 1994 [37]. Many subsequent studies have confirmed these original findings [23,[38][39][40][41][42]. Gnudi et al reported that women with femoral fractures had longer HAL, wider FND and larger NA than controls [40].…”

Relationship Between Femur Bone Mineral ection Density, Body Mass Index and Dental Panoramic Mandibular Cortical Width in Diagnosis of Elderly Postmenopausal Women With Osteoporosis

“…A recent innovation in non-invasive bone mass measurement is DXA which offers a lower absorbed radiation dose, higher spatial resolution and greater scan speed [11]. There is also incontrovertible evidence that BMD as measured by DXA, particularly at the proximal femur, is the main determinant of hip fracture risk [12].…”