Digital X-ray radiogrammetry (DXR) in patients with fractures

Background Patient screening in Fracture Liaison Services to prevent secondary fractures should be effective, fast and easily accessible. Tools such as FRAX can be used for fracture risk assessment, but collection of the required information is often challenging in busy accident and emergency wards. Digital x-ray radiogrammetry (DXR) measures bone mineral density of metacarpal bones from a normal hand x-ray image.

Methods DXR and FRAX assessments were performed in 160 female low energy fracture patients (aged 50–74 years) treated at the accident and emergency ward of Mikkeli Central Hospital, Finland, during winter 2016–2017. Additional DXA (dual-energy X-ray absorptiometry) measurements were performed in patients whose DXR T-score was below -1 SD (n = 116).

Results DXR and FRAX results showed moderate correlation (r = 0.47; p < 0.001). At a T-value threshold of -1 SD, DXR recognized elevated FRAX-risk with a sensitivity of 91% and specificity of 52%. According to the FRAX assessment alone, further DXA measurement would have been needed for 110 patients, i.e. those with an elevated or high FRAX-risk. By targeting the DXA assessment only to those with DXR osteopenia and FRAX-risk of 10–19%, only 38 patients would have needed the DXA. In patients with DXR T < -1, DXR identified osteoporosis better than FRAX (AUC: DXR / FRAX = 0.75 / 0.63).

Conclusions We propose DXR measurements as a primary screening technique, which would allow identification of osteopenia patients for secondary FRAX screening, thereby reducing the need for the more demanding and expensive DXA measurements in fracture patients.