REMS Fragility Score (Left Femur)

Bone density helps predict fractures, but fractures also occur in people whose density doesn't meet the criteria for osteoporosis. The REMS fragility score adds an ultrasound-derived estimate of bone fragility. Higher femoral scores have predicted later hip fractures in prospective studies, though its role in choosing and monitoring treatment is less established than its ability to separate groups by risk.

This result comes from your left femoral neck. That's the narrow stretch of bone below the ball of the hip joint. REMS uses ultrasound without ionizing radiation, and portable equipment allows scanning at a bedside.

How the Score Is Built

REMS stands for radiofrequency echographic multi-spectrometry. Software analyzes the returning ultrasound signals and compares their patterns with reference signals from people with and without fragility fractures. The calculation uses reference models matched to characteristics including age, sex and body size. It estimates fragility from those signal patterns.

The fragility score runs from 0 to 100, with higher values indicating greater estimated fragility. The number isn't your percentage chance of breaking a hip. The same examination also produces a separate bone mineral density estimate and T-score. A T-score compares density with a young-adult reference population.

What the Fracture Studies Show

Evidence about the femoral fragility score needs to be separated from evidence about the spine score and about REMS bone density. These are different outputs, even when they come from the same examination.

The direct hip-score evidence is promising. It does not yet show that adding the score to usual care prevents more fractures, or that lowering it through treatment reduces your risk. Several authors of the 2023 prediction study held stock in the device manufacturer or had an advisory relationship with it.

How Much the Score Reflects Age

A 2026 study examined results from 209 people at one REMS clinic. A mathematical model using age alone accounted for more than 95% of the differences in femoral fragility scores within that group. This raises a specific question about how much information the score adds beyond age for an individual person.

The same paper also changed the age and weight entered during repeat scans of five volunteers. Those experiments changed the REMS bone density estimate despite there being no plausible corresponding change in bone over the short study period. They did not establish how much changing entered weight changes the fragility score.

The strong relationship with age and the prospective fracture findings can both be true, because age itself predicts fracture risk. The single-clinic study doesn't prove that the score contains no useful ultrasound information, but it does argue against treating the result as a direct measure of bone structure independent of age.

What Studies in Specific Conditions Show

• Type 2 diabetes: fracture risk can be higher even when bone density is normal or high. In a study of 223 people with diabetes, those with previous major osteoporotic fractures had higher femoral and lumbar fragility scores. This supports further evaluation of the score in diabetes, but the study did not test future fractures.
• Inflammatory spine arthritis: a study of 90 people with radiographic axial spondyloarthritis and 100 controls found higher lumbar fragility scores in the arthritis group. This disease causes inflammation and structural changes in the spine. The finding concerns the spine score and cannot be assumed to apply to the left femoral score.
• Osteogenesis imperfecta: studies have explored REMS bone density in adults with this inherited brittle-bone disorder. Those density studies do not establish how accurately the femoral fragility score predicts fractures in this condition.
• Limited mobility: bedside REMS can make bone assessment more accessible. A study of 260 older adults included both care-home residents and outpatients. More than half of the care-home subgroup met the study's definition of severe osteoporosis, while about one in eight received osteoporosis treatment. These findings were based on density and fracture history, not validation of the hip fragility score.

Where REMS and DXA Agree and Disagree

DXA uses low-dose X-rays to measure bone density. In a large European study, quality-checked REMS femoral density results identified about 90% of the women classified as having osteoporosis by DXA and correctly classified about 95% of those without DXA-defined osteoporosis. Those figures describe agreement between density methods, not the fragility score's accuracy for predicting fractures.

Agreement has been weaker in some other populations. Among 148 geriatric outpatients, the femoral-neck REMS density result identified only 46% of those classified as having osteoporosis by DXA. A reassuring REMS density result therefore cannot reliably exclude DXA-defined osteoporosis in a similar population.

Spinal arthritis, vertebral compression and abdominal artery calcification can inflate lumbar DXA density. Studies suggest that REMS density is less affected by some of these artifacts. That advantage concerns particular measurements and sites; it does not establish that a left-femur fragility score is more accurate whenever the two examinations disagree. Diabetes can weaken bone despite preserved density, which is a different problem from an imaging artifact.

A small study of 20 people receiving peritoneal dialysis found that changes in REMS and DXA bone density tracked poorly together. DXA detected a decline in femoral-neck density that did not reach statistical significance with REMS, but the difference between the methods' time trends was itself not statistically significant. The study did not measure treatment-related changes in fragility score.

When Results Can Be Misleading

• Incorrect personal details: the calculation uses age, sex and body-size information. Accurate entries matter, and experimental evidence shows that altered age or weight entries can change the accompanying density estimate.
• Poor positioning or signal quality: probe placement, scan depth and focus affect acquisition. Limited access to the hip or difficulty holding the required position can prevent a valid scan.
• Confusing outputs: a femoral fragility score, a lumbar fragility score and a bone density T-score describe different things. Their numbers cannot be substituted for one another.
• A replaced left hip: REMS cannot assess the native femoral-neck bone at a hip replaced by a total or partial hip replacement. An eligible opposite hip is a separate measurement.
• Overreading a reassuring result: previous fractures, falls and medication exposure remain relevant even when the score looks favorable. The scan does not provide a complete assessment of fracture risk.

Interpreting a Trend

Repeated femoral measurements can be highly reproducible under controlled conditions. Reproducibility establishes consistency; it doesn't establish that a change over months measures a treatment benefit.

A least significant change is the smallest difference expected to exceed measurement noise. A value established for REMS bone density cannot automatically be used for the fragility score. Even a score change larger than its measurement noise would need to be interpreted alongside changes in personal details, bone density and clinical risk. There is no established amount of femoral-score reduction that proves fracture risk has fallen.

Studies of osteoporosis treatment using REMS have often followed bone density. For example, a study of denosumab in women receiving breast-cancer endocrine therapy reported density changes but explicitly did not monitor fragility score. Evidence for one output cannot establish treatment response for the other.