The incidence of osteoporotic hip fracture increases in postmenopausal women with low hip bone mineral density (BMD). Dual
X-ray absorptiometry (DXA) is the most commonly used technique for the assessment of bone status and provides good measurement
precision. However, DXA affords little information about bone architecture. Quantitative ultrasound (QUS) systems have been
developed to evaluate bone status for assessment of fracture risk. Our study was designed to assess a new QUS system from
Hologic, the Sahara; to compare it with a previous model, the Walker-Sonix UBA 575+; and to investigate whether it is able
to discriminate between women with and without fracture. Using both ultrasound devices, the measurements were performed at
the heels of 33 postmenopausal women who had recently sustained hip fracture. A control group of 35 age-matched postmenopausal
women was recruited for comparison. The total, neck and trochanter femoral BMD values were assessed using DXA for both groups.
QUS and DXA measurements were significantly lower in fractured patients (
p<0.005) than in the control group. The short-term, mid-term and standardized short-term precisions were used to evaluate the
reproducibility of the two QUS systems. The Sahara showed a better standardized coefficient of variation for broadband ultrasound
attenuation (BUA) than did the UBA 575+ (
p<0.001). The correlation of BUA and speed of sound (SOS) between the two QUS devices was highly significant, with an
r value of 0.92 for BUA and 0.91 for SOS. However, the correlation between DXA and ultrasound parameters ranged from 0.28 to
0.44. We found that ultrasound measurements at the heel were significant discriminators of hip fractures with odds ratios
(OR) ranging from 2.7 to 3.2. Even after adjusting the logistic regressions for total, neck or trochanter femoral BMD, QUS
variables were still significant independent discriminators of hip fracture. The areas under the ROC curves of each ultrasound
parameter ranged from 0.75 to 0.78, and compared very well with femoral neck BMD (
p>0.05). In conclusion, our study indicated that the calcaneal QUS variables, as measured by the Sahara system can discriminate
hip fracture patients equally as well as hip DXA.
Key words:Bone density – Hip fracture – Osteoporosis – Quantitative ultrasound
Received: 29 October 1999 / Accepted: 7 September 1999