|Beitragstitel||CT-based evaluation of bone density in fragility fractures of the sacrum – a matched case-control-analysis|
The gold standard for measuring the bone mineral density is dual energy x-ray absorptiometry (DEXA), which is, however, not always readily available. Computed tomography (CT), on the other hand, is a standard diagnostic procedure in patients with fragility fractures of the pelvis. CT can allow for an evaluation of the bone mineral density using the absolute density values (Hounsfield Units; HU).
The aim of this study was to compare the CT-based bone density measured by HU in patients with and without fragility fractures of the sacrum.
Consecutive patients aged > 50 years who sustained as fragility fracture of the sacrum between 01/2006 and 10/2016 and had an in-house DEXA of the lumbar spine were compared to patients of same age and gender who had a fall from standing height without fracture (matched case-control-analysis; n=30) and a retrospective chart review was performed. In CT scans, bone density was measured by HU in the Corpus and Alae of S1.
Patients with a sacral fracture showed a significantly lower average bone density in the Corpus of S1
(HU 88±22) when compared to the matched control group without fracture (HU 119±46; Paired Samples T test, p=0.039). The CT-based bone density did not correlate with the DEXA values of the lumbar spine (R=0.195, p=0.302).
In the regional analysis, especially the Alae of the fracture group had a lower bone density when compared to the control (HU -27±29 vs. 11±30, Paired Samples T test, p=0.001).
Patients with fragility fractures of the sacrum showed a lower general and regional bone density of the sacrum when compared to a control group matched for age, gender and trauma.
This difference was especially seen when comparing the Alae of S1, those being the possible Achilles’ tendon of the sacrum.