Assessing bone structure in the prediction of osteoporotic fractures

Update on Imaging-Based Measurement of Bone Mineral Density and Quality

PURPOSE OF REVIEW

Patients with inflammatory arthropathies have a high rate of fragility fractures. Diagnostic assessment and monitoring of bone density and quality are therefore critically important. Here, we review standard and advanced techniques to measure bone density and quality, specifically focusing on patients with inflammatory arthropathies.

RECENT FINDINGS

Current standard procedures are dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT). DXA-based newer methods include trabecular bone score (TBS) and vertebral fracture assessment (VFA). More advanced imaging methods to measure bone quality include high-resolution peripheral quantitative computed tomography (HR-pQCT) as well as multi-detector CT (MD-CT) and magnetic resonance imaging (MRI). Quantitative ultrasound has shown promise but is not standard to assess bone fragility. While there are limitations, DXA remains the standard technique to measure density in patients with rheumatological disorders. Newer modalities to measure bone quality may allow better characterization of bone fragility but currently are not standard of care procedures.

Prevalence of undisclosed osteoporosis in patients with minimal trauma fractures: a prospective cohort study

Despite epidemiologic evidence for the presence of osteoporosis in patients with minimal trauma fractures, screening programs have not been routinely established in Australian ambulatory care clinics. Our study assessed the prevalence of osteoporosis and osteopenia in patients at a tertiary care hospital to gather local data to support policy change that favors bone mineral density screening. Our prospective observational study enrolled 115 patients, aged > 40 years, who had experienced a minimal trauma fracture. Inclusion criteria required that the patient had no history of testing for osteoporosis or metabolic bone disease/major pathology. The patients were recruited over a 6-month period. Eleven participants were excluded and 7 participants withdrew from the study, with a total of 97 patients completing the study. Participants were assessed for osteoporosis risk via bone mineral density measurement by dual-energy x-ray absorptiometry and blood screening for bone mineral levels, 25-hydroxyvitamin D, and parathyroid hormone levels. In our study patients, the prevalence of previously undiagnosed osteoporosis was 19%, undiagnosed osteopenia, 50%, and the standard bone mineral density was 32%. The most common risk factors for osteoporosis/osteopenia were smoking (22%), alcohol intake (16%), and corticosteroid use (9%). In 67% of patients, 25-hydroxyvitamin D level was in the low clinical range in 51% of patients, magnesium levels were in the high range and 18% of patients had elevated serum parathyroid levels. At month 12 of our study, 80 participants were available for follow-up: 2 patients had sustained a second fracture (1 was minimal trauma); 6 patients had required further surgery (3 fracture fixations, 3 for removal of internal fixation devices); 26 patients continued treatment regimens with calcium and 25-hydroxyvitamin D supplementation; and 28 patients had been prescribed bisphosphonates, with 22 patients complying with the prescription. The high prevalence of previously undiagnosed low bone mass in our study patient population, each of whom had experienced minimal trauma falls, provides impetus for the provision of osteoporosis screening programs and corresponding treatment as needed.