BMD - BOTH HIP JOINTS

A BMD - BOTH HIP JOINTS examination is a bone mineral density test that measures the mineral content of the right and left proximal femur using dual-energy X-ray absorptiometry, commonly called DXA or DEXA. The scan provides quantitative information about bone strength and helps doctors evaluate the risk of osteoporosis and fragility fractures.

The examination commonly measures bone density at the femoral neck and total-hip regions on both sides. The femoral neck is the narrow area below the ball of the hip joint and is an important site for assessing osteoporosis-related fracture risk. Scanning both hips can reveal side-to-side differences and provide usable information when one hip contains an abnormality, previous surgery or another factor that affects measurement.

DXA uses two low-dose X-ray beams with different energy levels. A computer calculates how much of each beam is absorbed by bone and estimates the bone mineral density, usually expressed in grams per square centimetre. The results are commonly reported as a T-score, Z-score and absolute BMD value.

This examination assesses bone mineral density rather than the cartilage, ligaments, tendons or muscles of the hip joint. It is not a test for diagnosing all causes of hip pain. Patients with suspected arthritis, fracture, labral injury or soft-tissue disease may require an X-ray, CT, MRI, ultrasound or another examination.

Benefits of the Test

• Measures bone mineral density at the right and left femoral neck and total-hip regions.
• Helps identify low bone mass and osteoporosis when interpreted using appropriate criteria.
• Supports assessment of future fragility-fracture risk.
• Allows comparison between the right and left hips.
• May provide an alternative usable hip measurement when one side is affected by an artifact or structural problem.
• Can help establish a baseline before or during osteoporosis treatment.
• May support monitoring of bone-density changes over time.
• Uses a very low dose of ionizing radiation.
• Is non-invasive, painless and usually completed quickly.
• Requires little preparation and no injection or anaesthesia.

Why Doctors Recommend This Test

Doctors may recommend bilateral hip BMD testing when a patient has risk factors for osteoporosis or fragility fracture. Important risk factors can include increasing age, menopause, low body weight, a previous low-trauma fracture, a family history of hip fracture, long-term glucocorticoid treatment, smoking, excessive alcohol use, reduced mobility or certain chronic medical conditions.

The test may be requested after a fracture caused by a minor fall or another level of trauma that would not usually break healthy bone. Such fractures may indicate reduced bone strength and can prompt assessment for osteoporosis and underlying causes of bone loss.

Patients taking medicines that can affect bone health may undergo BMD testing before or during treatment. Long-term corticosteroid use is a common example, but several other medicines and medical conditions can influence bone density. The treating doctor determines whether testing is appropriate and how often it should be repeated.

Conditions associated with reduced bone density may include certain endocrine, nutritional, gastrointestinal, kidney, liver, inflammatory and hormonal disorders. BMD results are interpreted together with the patient's age, sex, medical history, fracture history, laboratory findings and treatment status.

Scanning both hips can be useful when anatomical differences, degeneration, previous injury or another condition affects one side. According to current professional positions, bilateral hip measurements can be used to report T-scores or Z-scores. For diagnostic classification, the lowest appropriate score from the right or left femoral neck or total hip is considered rather than averaging the diagnostic scores.

For follow-up examinations, the interpreting clinician considers whether the same scanner, positioning and analysis method were used. Small apparent differences between examinations may reflect measurement variation rather than true biological change. Meaningful monitoring requires comparison with the facility's calculated precision and least significant change.

Preparation Before Test

BMD testing requires little preparation. Patients can generally eat and drink normally on the day of the examination. Calcium supplements are commonly avoided for at least 24 hours before the scan unless the diagnostic centre provides different instructions. Regular medicines should not be stopped without medical advice.

Wear loose, comfortable clothing without metal zippers, buttons, buckles or belts around the hip and pelvic region. Keys, wallets, mobile phones and other objects should be removed from pockets. Patients may be asked to change into a gown if clothing contains metal that could interfere with the scan.

Tell the imaging team about recent examinations involving barium contrast, oral contrast, injected contrast or certain nuclear-medicine tracers. Residual contrast material can affect DXA measurements, and the BMD test may need to be scheduled after an appropriate interval.

Bring previous BMD or DXA reports and, when possible, information about the scanner or facility where they were performed. Comparison is most reliable when follow-up studies use the same machine and standardized positioning. Reports from different devices may not always be directly comparable.

Inform the technologist about previous hip fractures, hip replacement, metal implants, surgery, severe arthritis, limited movement or pain that affects positioning. A hip containing a prosthesis generally cannot be assessed in the standard way, so the opposite hip or another skeletal site may be used according to professional guidance.

Women who are pregnant or may be pregnant must inform the referring doctor and imaging team. Although DXA uses a very low radiation dose, non-urgent bone-density testing is generally postponed during pregnancy unless there is a specific medical reason to proceed.

During the examination, the patient lies on a padded table. Each leg is positioned with the hip rotated inward using a support so that the femoral neck can be measured accurately. The patient must remain still while the scanner passes over the selected area. Correct positioning is important because rotation can alter the measured result.

Normal Reporting Time

The scan of both hips is usually completed within approximately 10 to 20 minutes, although registration, positioning and review of previous studies can increase the total appointment time. Patients with pain, restricted movement or previous surgery may require additional positioning time.

Many routine BMD reports may be available on the same day or within 24 hours. Reporting time can vary depending on the centre's workflow, the need for physician interpretation, technical review or comparison with previous studies. Patients should confirm the expected reporting time with Focus Diagnostics.

The report may include absolute bone mineral density values, T-scores, Z-scores and comments about technical limitations. The result should be reviewed by the referring doctor, who will interpret it together with the patient's age, menopausal status, fracture history, medicines and other risk factors.

A BMD result alone does not decide treatment. The doctor may also use a validated fracture-risk calculator and may request blood or urine tests to evaluate vitamin D, calcium, thyroid, parathyroid, kidney or other factors affecting bone health.

Who Should Take This Test?

Bilateral hip BMD testing may be appropriate for postmenopausal women, older men and other adults who meet clinical criteria for osteoporosis assessment. The exact age and testing recommendations depend on the patient's sex, risk factors, medical history and applicable professional guidance.

Younger adults may require BMD testing when they have a fragility fracture, long-term steroid use, a condition associated with bone loss or another significant clinical risk. Routine testing of healthy young people without risk factors is generally not necessary.

The test may be recommended for patients starting or receiving osteoporosis treatment. A baseline measurement can help document bone density before therapy, while appropriately timed follow-up scans may help assess response. Repeating the test too soon may not show a meaningful change.

Patients with loss of height, spinal curvature or unexplained back pain may need vertebral evaluation in addition to hip BMD. Hip-only scanning does not directly assess lumbar-spine density or identify every vertebral fracture. The doctor may request additional skeletal sites depending on the clinical question.

People who already have bilateral hip replacements may require measurement at other recommended sites because standard hip analysis may not be possible. The imaging team and interpreting physician determine the most appropriate alternative.

Detailed Information

The hip measurement includes regions of interest such as the femoral neck and total hip. Precise positioning and software placement of these regions are essential. Incorrect leg rotation or analysis can produce inaccurate values, so the examination should be performed by trained personnel.

A T-score compares the patient's bone density with the average peak bone density of a healthy young-adult reference population. In appropriate populations, a T-score of -1.0 or above is generally considered normal, a score between -1.0 and -2.5 indicates low bone mass, and a score of -2.5 or below meets the densitometric threshold for osteoporosis.

These T-score categories are not applied identically to every patient. Z-scores are generally more relevant for premenopausal women, men younger than 50 and children. A Z-score compares the patient's BMD with values expected for people of a similar age and sex. Clinical interpretation must follow appropriate professional guidance.

When both hips are scanned, the lowest appropriate T-score or Z-score from the right or left femoral neck or total hip is used for diagnostic classification rather than the average of the diagnostic scores. For monitoring when both hips have been measured repeatedly, mean bilateral total-hip BMD may have a role according to current professional positions.

Low bone density is an important fracture-risk factor, but fractures are also influenced by age, previous fractures, falls, family history, smoking, alcohol, medicines and medical conditions. A person with a score outside the osteoporosis range may still have substantial fracture risk, while not every person with osteoporosis will experience a fracture.

Degenerative changes, previous fractures, metal, calcification and positioning errors can affect BMD measurements. The interpreting clinician may exclude an invalid region or recommend another site. Reports should note significant technical limitations that may influence interpretation.

Changes over time should be assessed using absolute BMD values rather than comparing score categories alone. The difference must exceed the testing facility's least significant change before it can confidently be considered a real change rather than measurement variation.

For reliable follow-up, patients should ideally return to the same facility and scanner. Different manufacturers use different reference databases and calibration methods. If another machine is used, direct comparison may be limited unless appropriate cross-calibration has been performed.

DXA exposes the patient to a very small amount of ionizing radiation. No radiation remains in the body after the examination. The scan does not require contrast material, needles, sedation or recovery time, and patients can resume normal activities immediately.

The final result should be reviewed by the referring doctor. Management may include nutrition advice, adequate calcium and vitamin D when appropriate, weight-bearing exercise, fall-prevention measures, review of medicines, treatment of an underlying condition or osteoporosis medication. Patients should not start high-dose supplements or prescription treatment solely from the scan result without medical advice.