InstalabREMS Fragility Score (Right Femur)
Should you take a REMS Fragility Score (Right Femur) test?
This test is most useful if any of these apply to you.
About REMS Fragility Score (Right Femur)
Most hip fractures in older adults follow a fall. DXA uses X-rays to measure bone mineral density. Density helps predict who will fracture, but fractures also occur in people whose density is outside the osteoporosis range. The arrangement of bone tissue contributes to strength too. Studies using detailed CT scans of the wrist and shin have linked bone structure to fracture risk independently of density, though those findings don't validate a hip ultrasound score.
The REMS fragility score estimates skeletal fragility from ultrasound signals at your right hip. It has studies following future fractures behind it, including research in women and men, but its role in treatment decisions and long-term monitoring remains unproven. It's an emerging measure to interpret alongside established fracture assessment.
What the Score Measures
REMS stands for radiofrequency echographic multi-spectrometry. It analyzes frequency patterns in raw ultrasound echoes from the femoral neck. This is the narrow section of thigh bone just below the ball of the hip joint. The examination uses no ionizing radiation.
Software compares portions of your signal with reference patterns from people with and without fragility fractures, accounting for characteristics such as age, sex and body size. The score reflects the proportion classified as resembling the fracture group. It runs from 0 to 100 and is intended as an indirect indicator of bone quality. It doesn't directly measure the thickness of individual bone struts or the porosity of the outer shell.
The same scan produces a separate REMS bone density estimate and T-score. A T-score compares density with a young-adult reference population. The fragility score isn't a T-score or a percentage chance that you'll break your hip, and these outputs can't be converted into one another. Hip studies generally evaluate femoral measurements against subsequent hip fractures; they don't establish a separate prediction specifically for fractures of your right hip.
What the Fracture Studies Show
| Who Was Studied | What Was Measured | What Was Found |
|---|---|---|
| 1,989 women and men, including 1,812 femoral scans, followed for up to five years | Femoral fragility score and later hip fractures | The score ranked someone who later fractured above someone who didn't about 78% of the time in women and 81% in men. |
| About 4,000 women with spine and/or hip scans followed for five years | Seven classes combining REMS density and fragility score | Hip fracture occurrence increased across the femoral risk classes. |
| 175 people recruited with primary osteoporosis or bone loss related to spinal cord injury | Femoral fragility score and previous fractures | Scores differed between people with and without fractures; this comparison couldn't establish prediction of future fractures. |
In the study of women and men, the ability to distinguish people who later fractured remained after adjustment for age and body size, although it weakened. Ranking two people correctly is different from accurately estimating your absolute chance of fracture. Some authors held shares in, or advised, the device manufacturer.
The larger study of women supports an association between the combined score and later fractures. It didn't compare the approach directly with DXA or established risk calculators measured at the same time, and its risk-class comparisons weren't adjusted for other clinical risk factors. Treatment during follow-up wasn't recorded. Neither study establishes that using the score to choose treatment prevents more fractures.
In the smaller osteoporosis study, femoral scores also tracked FRAX estimates in the subgroup with primary osteoporosis and no previous fracture. FRAX calculates your ten-year fracture probability from clinical risk factors, with an option to include femoral-neck DXA density. Correlation between two risk measures doesn't show that combining them improves decisions.
Evidence From Other REMS Measurements
A study following about 1,500 women for an average of 3.7 years found that osteoporosis-range REMS femoral T-scores were associated with about 2.8 times the odds of a new fragility fracture. The corresponding DXA estimate was about 2.7 times. That study evaluated density T-scores, so it supports a different output from the scan.
A conference report in 533 women found that the lumbar-spine fragility score ranked women who later fractured above those who didn't about 80% of the time, compared with 64% for the DXA T-score. A separate study of 90 people with radiographic axial spondyloarthritis and healthy controls found higher spinal fragility scores despite similar density measurements. Axial spondyloarthritis causes inflammation and structural changes in the spine. Both findings concern the spinal score, and neither directly establishes the performance of your right-femur score.
When a Density Reading Is Hard to Interpret
Arthritis-related bone growth, vertebral fractures and calcium deposits in the aorta can make lumbar-spine DXA density look artificially high. These are mainly problems with interpreting the spine image; they don't automatically invalidate a hip DXA result. A study of 70 people receiving osteoporosis treatment found greater differences between REMS and DXA spinal density in people with severe vertebral fractures, vascular calcification or diabetes. It suggested that REMS might avoid some distortions, but it didn't prove that the right-hip fragility score measures bone structure accurately.
REMS has also been used to assess density in 41 adults with osteogenesis imperfecta, compared with 36 controls. This inherited disorder makes bones fragile. A separate study of 260 older adults included care home residents and outpatients and showed that portable REMS density assessment was feasible in people who had difficulty accessing DXA. These studies support possible uses for the scanning technology; they don't establish the clinical value of this specific score.
How Age and Body Size Affect the Result
In a 2026 study of 209 people, models using demographic information explained more than 95% of the variation in femoral fragility scores, with age the dominant factor. In a separate experiment involving five volunteers, changing only the age entered into the machine reduced femoral REMS density by about 6.3% per added decade. That experimental figure concerns the density estimate, not the fragility score.
This raises a question about how much information the score adds beyond age and body size. It doesn't erase the fracture associations, but an unusually high or low value hasn't been validated as a special indicator of bone structure. The study used one device and included relatively few men.
Agreement With DXA
Studies comparing REMS with DXA usually compare their density estimates. In a European study recruiting about 4,300 women, femoral REMS scans that passed quality checks identified about 90% of DXA-defined osteoporosis and correctly classified about 96% of women without it. These figures describe density classification, not fragility-score accuracy.
Results have been less consistent in other settings. In 148 geriatric outpatients with a median age of 75, REMS density detected roughly half of DXA-defined osteoporosis at the hip. A negative result therefore couldn't reliably exclude osteoporosis in everyone. Poor agreement has also been reported in osteoporosis related to spinal cord injury. The 2024 UK osteoporosis guideline doesn't recommend REMS for diagnosing osteoporosis.
When Results Can Be Misleading
- Incorrect personal details: age, weight and height help determine the reference comparison, so inaccurate entries can distort interpretation.
- Acquisition errors: incorrect probe position, focus or scanning depth can produce unsuitable data. Operator training and scan-quality checks matter.
- A replaced right hip: a total or partial hip replacement prevents assessment of the original femoral target. Some fracture-fixation hardware may still allow scanning if enough native bone is accessible.
- A different measurement: a spine fragility score, REMS density estimate, DXA T-score or CT-based structural score answers a different question. Evidence or precision limits for one shouldn't be transferred to another.
- A population unlike the validation groups: much of the prospective evidence comes from white European adults. Performance in other populations and complex bone disorders is less certain.
What a Trend Can Establish
Short-term repeat scans have shown good reproducibility for the femoral fragility score itself. Reproducibility doesn't establish that changes over months reflect stronger bone or reduced fracture risk. Precision figures published for REMS density cannot be applied to the fragility score.
Longitudinal density studies also need careful interpretation. In 20 people receiving peritoneal dialysis, individual changes measured by REMS and DXA didn't correlate. That small study concerned density, but it illustrates why evidence for monitoring must be evaluated separately from evidence for a single measurement.