Approximately 1.7 million hips are fractured each year, most often due to progressive bone demineralization from osteoporosis. While there is a lot of cool technology aimed at fixing hip fractures, it would be even better if we could find ways to prevent the fractures in the first place.
Researchers at the Karolinska Institute in Sweden have found a relatively easy technique that may be used to screen for those at risk for hip fractures. In a paper published last week in European Radiology the scientists describe how they analyzed 18,824 left-hand radiographs from over 8,000 patients using digital X-ray radiogrammetry (DXR). They correlated measurements of bone cortex porosity and thickness with whether the patients suffered a hip fracture following the X-ray. According to the Karolinska press release:
Analysis of the sub-group of 122 patients who had suffered a post-X-ray hip fracture showed that they had significantly lower bone density than those who had not had a hip fracture, a result that held up also when adjusted for age. The DXR technique uses a normal X-ray of the hand to analyse the thickness and texture (i.e. small variations in density) of the metacarpal bones. The analysis is automatic and includes around 1,000 measurements. The standard method of measuring bone density is currently DXA (dual-energy X-ray absorptiometry).
In this study, the researchers showed that DXR is at least as effective as DXA, which means that the former might one day be an important feature of osteoporosis examinations as part of a general screening. Several pilot projects are underway in several counties to ascertain whether DXR screening of bone density is a useful way of preventing hip fractures.
Two of the study authors are employees of Sectra, a medical imaging company specializing in orthopedics and rheumatology. One of their medical experts is quoted in the press release speaking about the potential of combining DXR-based osteoporosis screening with mammographies given the similar equipment used (men would presumably be screened under different circumstances) :
Sectra OneScreen can easily be combined with mammograms by taking a hand X-ray at the same time as breast images using the same radiology equipment. The extra examination takes less than 30 seconds…”If all mammograms were combined with osteoporosis screenings, a portion of the hip fractures occurring every year could be prevented, which would reduce personal suffering and generate major cost savings for the healthcare sector.”
Medgadget interviewed lead study author, Michael Wilczek, of the Karolinska Institute about the team’s findings:
Shiv Gaglani, Medgadget: How is hip fracture risk currently assessed?
Michael Wilczek: Hip fracture risk is currently assessed with risk assessment instruments, FRAX being the most commonly used, which are based on a combination of hereditary and clinical risk factors. Ideally such a risk assessment tool is also combined with a dual-energy x-ray absorptiometry (DXA) scan, which provides a measurement of bone density. A DXA scan is required to diagnose osteoporosis.
Medgadget: Can you discuss the pros and cons of DXR as compared with DXA?
Wilczek: DXR has several advantages compared to DXA. It is fast, each examination takes about 1-2 minutes whereas a DXA scan normally takes between 15-20 minutes. DXR only requires standard x-ray equipment that can take plain radiographs and an internet connection in order to function. DXA is more complicated and requires specific devices and certified staff that can operate them. Thus DXR has the potential to be widely available and reach areas without current access to DXA. Another theoretical benefit is the high reproducibility of DXR that has been shown in previous studies.
Medgadget: Do you have a sense of potential screening recommendations using DXR? For example, Sectra mentioned that DXR could be combined with mammography screening.
Wilczek: Our previous study results suggest that DXR can be used for a selective screening, e.g. for patients seeking the emergency department. We hypothesize that DXR can also be used for general screening, for example in conjunction with mammography. This is something that we are currently investigating. The method’s ability to estimate hip fracture risk in a general population needs to be studied as do the health economical aspects of osteoporosis screening with DXR. We expect to have those answers in a couple of years.
To learn more:
Read the paper in European Radiology: Digital X-ray radiogrammetry of hand or wrist radiographs can predict hip fracture risk—a study in 5,420 women and 2,837 men
Read the press release from the Karolinska Institute: Method for assessing hand bone density may prevent hip fractures