In vivo discrimination of hip fracture with quantitative computed tomography: Results from the prospective European Femur Fracture Study (EFFECT)

Abstract

In assessing osteoporotic fractures of the proximal femur, the main objective of this in vivo case-control study was to evaluate the performance of quantitative computed tomography (QCT) and a dedicated 3D image analysis tool [Medical Image Analysis Framework-Femur option (MIAF-Femur)] in differentiating hip fracture and non-hip fracture subjects. One-hundred and seven women were recruited in the study, 47 women (mean age 81.6 years) with low-energy hip fractures and 60 female non-hip fracture control subjects (mean age 73.4 years). Bone mineral density (BMD) and geometric variables of cortical and trabecular bone in the femoral head and neck, trochanteric, and intertrochanteric regions and proximal shaft were assessed using QCT and MIAF-Femur. Areal BMD (aBMD) was assessed using dual-energy X-ray absorptiometry (DXA) in 96 (37 hip fracture and 59 non-hip fracture subjects) of the 107 patients. Logistic regressions were computed to extract the best discriminates of hip fracture, and area under the receiver characteristic operating curve (AUC) was calculated. Three logistic models that discriminated the occurrence of hip fracture with QCT variables were obtained (AUC ¼ 0.84). All three models combined one densitometric variable-a trabecular BMD (measured in the femoral head or in the trochanteric region)-and one geometric variable-a cortical thickness value (measured in the femoral neck or proximal shaft). The best discriminant using DXA variables was obtained with total femur aBMD (AUC ¼ 0.80, p ¼ .003). Results highlight a synergistic contribution of trabecular and cortical components in hip fracture risk and the utility of assessing QCT BMD of the femoral head for improved understanding and possible insights into prevention of hip fractures. ß

Predicting Hip Fracture Type With Cortical Bone Mapping (CBM) in the Osteoporotic Fractures in Men (MrOS) Study

“…Weight, height, and age results agree well with a previous discriminative study on women,20 confirming that age is a stronger predictor, as well as discriminator, of fracture than either weight or height. However, age shows much more significance for neck fracture than for trochanteric fracture, which may well be related to the particular regions associated with age‐related bone loss23 and how these compare to those regions associated with each fracture type in Fig.…”

“…In contrast to QCT, the DXA‐derived areal BMDs contain some measure of size as well as volumetric density, and this may contribute to the improved performance for neck fracture from what is otherwise a less direct measurement of BMD. Nevertheless, hazard ratios between DXA and QCT BMD are largely similar, supporting the general results from previous studies that fail to show any significant benefit from adding such QCT measurement to fracture predictors which already include DXA measurements 19, 20, 29…”

“…AUCs for these models in Table 4 are somewhat smaller than have occasionally been recorded in the literature. Similar models, including DXA variables, have reported AUCs for any fracture type of 0.8619 and 0.80,20 rather than our value of 0.78. The former was based on the same study as this current work, though with a different cohort and a smaller number of cases.…”

“…It also reports on a much larger number of cases than previously published results: 99 rather than the previously reported 40. As a result, we consider these cases in two separate fracture groups (trochanteric and neck fractures) for the first time in a male cohort, although there have been previous discriminatory analyses of fracture type in female cohorts 11, 18, 20. Using CBM we can show the different patterns of relationship between fracture type and cortical distributions and hence start to consider the assessment of not only whether a particular hip is at risk of fracture, but where that fracture is most likely to occur.…”

The importance of lag screw position for the stabilization of trochanteric fractures with a sliding hip screw: A subject‐specific finite element study

“…13,14 We analyzed our FE models with 75% of the bone density of the cadaveric bone taken from PhysiomeSpace in accordance with a recent imaging study that showed that the average bone mineral density (BMD) of femoral heads in hip fracture patients was 75% of the BMD of an age-matched fracturefree control group. 15 To calculate the tip-apex distance corresponding to the position of the lag screw, a best-fit sphere was calculated to match the surface nodes of the head. The coordinates of the apex were then obtained by taking into account the neckshaft angle and the femoral neck anteversion of the bone.…”