Musculoskeletal & Integumentary · Topic 5 of 11

Osteoporosis & Fragility Fractures

Musculoskeletal · bone health

Osteoporosis & Fragility Fractures

Osteoporosis is a T-score of −2.5 or lower or any fragility fracture; treat after a hip or vertebral fracture without waiting for DXA.

Key numbers

DXA T-score −2.5 or lowerT-score ≤ −2.5

Treat osteopenia if FRAX is highFRAX ≥ 20% or hip ≥ 3%

01 · Defined byDXA T-score −2.5 or lower

On DXA of the hip or spine, a T-score of −2.5 or lower defines osteoporosis; a T-score between −1.0 and −2.5 is osteopenia (low bone mass).

02 · Defined byHip or vertebral fragility fracture means osteoporosis

A hip or vertebral fragility fracture — from a fall from standing height or less — establishes osteoporosis regardless of BMD; start treatment without waiting for DXA. Wrist and humerus fractures also signal it.

03 · GiveBisphosphonates are first-line

Bisphosphonates are first-line — alendronate 70 mg orally once weekly, or zoledronic acid 5 mg IV once yearly if oral therapy is not tolerated — and cut vertebral and hip fractures by up to 50%.

Causes & risk factors

Why it happens

Very high risk: consider an anabolic agent firstAACE very high risk: fracture in the past 12 months, fracture on therapy, multiple fractures, T-score below −3.0, injurious falls, or FRAX > 30% (major) / > 4.5% (hip). Start injectable therapy, often an anabolic first.

Screen for secondary causes of bone lossLook for secondary causes: glucocorticoids, aromatase inhibitors, antiseizure drugs, hypogonadism, hyperparathyroidism, hyperthyroidism, vitamin D deficiency, CKD, malabsorption and myeloma. Check calcium, phosphate, 25-OH vitamin D, PTH and testosterone in men.

Diagnosis & monitoring

Work-up

Treat osteopenia if FRAX is high must knowIn osteopenia, treat when the 10-year FRAX risk is 20% or more for a major osteoporotic fracture or 3% or more for hip fracture (US thresholds).

Management

Orders

After hip fracture: zoledronic acid within 90 daysYearly zoledronic acid 5 mg IV started within 90 days of hip fracture repair cut new clinical fractures by 35% and all-cause deaths by 28% without impairing fracture healing (HORIZON-RFT).

Denosumab: never stop without a bisphosphonateDenosumab 60 mg SC every 6 months is an alternative, including with impaired renal function; stopping it causes rapid bone loss and multiple vertebral fractures, so transition to a bisphosphonate such as zoledronic acid.

Anabolics: teriparatide, abaloparatide, romosozumabAnabolic agents — daily SC teriparatide or abaloparatide (usually 2 years; the 2-year limit was lifted) or monthly romosozumab (1 year) — treat severe osteoporosis or antiresorptive failure; always follow with an antiresorptive.

Red flags & don'ts

Avoid harm

Correct hypocalcemia before denosumab avoidDenosumab is contraindicated in hypocalcemia, and advanced CKD carries a boxed warning for severe hypocalcemia; correct hypocalcemia before starting and give calcium and vitamin D supplements.

No romosozumab within 12 months of MI/stroke avoidRomosozumab carries a boxed warning for myocardial infarction, stroke and cardiovascular death; do not start it within 12 months of an MI or stroke.

Thigh pain on therapy: suspect atypical femur fracture complicationOsteonecrosis of the jaw and atypical femoral shaft fractures are rare with bisphosphonates and denosumab; new thigh or groin pain may herald an atypical fracture, which can be bilateral — image both femurs.

The rules

Know these

Screen women 65 and older with DXAUSPSTF 2025: screen all women 65 or older, and postmenopausal women under 65 at increased risk by a clinical risk tool, with DXA (grade B); evidence is insufficient to screen men (I statement).

Bisphosphonate holiday: 5 years oral, 3 IVIn lower-risk patients consider a bisphosphonate holiday after about 5 years of oral or 3 years of IV therapy (longer if risk stays high), watching for fracture or bone loss. Denosumab gets no holiday.

T-score or Z-score?

Commonly confused

Compares the patient with	Peak bone mass of a healthy young adult
Used for	Postmenopausal women and men 50 or older
Key cutoff	≤ −2.5 = osteoporosis; −1.0 to −2.5 = osteopenia

Teach & follow up

Patient education

Oral bisphosphonate: empty stomach, upright 30 minutesTake oral bisphosphonates fasting with a full glass of plain water and stay upright at least 30 minutes before food or other drugs; avoid with esophageal disorders, hypocalcemia or creatinine clearance under 35 mL/min.

Calcium 1200 mg, vitamin D 800 IU dailyPostmenopausal women and older men need about 1200 mg/day of calcium (diet plus supplement) and vitamin D 600–800 IU/day (more if deficient; target 25-OH vitamin D ≥ 30 ng/mL), plus exercise and fall prevention.

More detail

Reference

Show 6 reference facts

Use the Z-score (same age and sex) instead of the T-score for premenopausal women, men under 50 and children; a Z-score of −2.0 or lower is low for age — look for secondary causes.

Repeat DXA about 2–3 years into oral bisphosphonate therapy, after 3 years of IV therapy, and at the end of an anabolic course; compare absolute BMD (g/cm²) on the same machine.

Teriparatide is the anabolic agent used for glucocorticoid-induced osteoporosis; PTH analogs require a creatinine clearance above 35 mL/min.

Raloxifene and estrogen preserve bone but raise thromboembolism risk, so neither is first-line for osteoporosis alone; raloxifene suits women who cannot take bisphosphonates or denosumab.

Bisphosphonates can be started during the fracture hospitalization; concerns that they impair fracture healing have not been borne out.

After menopause women lose bone at about 2% a year for roughly 10 years; peak bone mass is reached around age 30.

Pearl

The first fragility fracture is the warning shot — treat it, because the next one is often a hip.

Sources · Merck Manual Professional — Osteoporosis (reviewed 2025) · USPSTF — Osteoporosis to Prevent Fractures: Screening (Final Recommendation, January 14, 2025) · Camacho PM et al. AACE/ACE Clinical Practice Guidelines for the Diagnosis and Treatment of Postmenopausal Osteoporosis — 2020 Update. Endocr Pract 2020;26(Suppl 1):1–46 · MDedge — New osteoporosis recommendations from AACE help therapy selection (summary of the 2020 AACE/ACE guideline: very-high-risk criteria) · Lyles KW et al. Zoledronic acid and clinical fractures and mortality after hip fracture (HORIZON-RFT). N Engl J Med 2007;357:1799–1809 · Alendronate sodium tablets prescribing information — DailyMed · Prolia (denosumab) prescribing information — DailyMed · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).