Osteoporotic Vertebral Compression Fracture

An osteoporotic vertebral compression fracture is a collapse of a vertebral body, most often at the thoracolumbar junction. It follows low energy loading (a fall from standing height, lifting, a cough, or no recalled injury) in a patient with low bone strength.

It is the commonest fragility fracture, and a marker of high risk of further fractures.

About 1.4 million occur worldwide each year; about 25% of women over 70 years and 40% of those over 80 years have at least one. Only about a third are clinically recognised, and the rest are found on imaging done for another reason.

Risk factors are age, female sex, previous fracture, low bone density, smoking, alcohol excess, low body weight and falls.

Others are glucocorticoid therapy (5 mg prednisolone daily or equivalent for over 3 months), hypogonadism, hyperparathyroidism, malabsorption and rheumatoid arthritis. Some drugs add risk (aromatase inhibitors, androgen deprivation, anticonvulsants, proton pump inhibitors long term).

After one vertebral fracture, the risk of another within the next year is about 20%. Complications are acute and chronic pain, progressive kyphosis, height loss, reduced lung function, abdominal pressure symptoms, loss of function, increased mortality (up to 20% higher than controls), nonunion with intravertebral vacuum cleft, and, rarely, neurological deficit from retropulsion.

Pathophysiology.

Loss of trabecular bone and microarchitecture reduces the strength of the vertebral body so that normal loads cause failure of the anterior column (wedge, biconcave or crush shapes). Anterior wedging increases thoracic kyphosis and moves the centre of gravity forward, which raises loads on adjacent vertebrae and causes a cascade of fractures. Pain arises from microfracture, periosteal stretch and muscle spasm.

Sudden severe focal back pain after minor loading, worse on standing, sitting and movement and eased by lying; spinal percussion tenderness; paraspinal spasm. Some fractures are painless, and found by loss of height (over 4 cm from young adult height or over 2 cm in a year), a dowager hump, rib-to-pelvis contact and abdominal protuberance. Radicular pain or neurological signs are unusual and require urgent imaging.

Examine height and weight, kyphosis, spinal tenderness, neurological state (including the legs and perianal sensation), gait, and balance.

• Radiographs (thoracolumbar spine, lateral and anteroposterior): vertebral height loss graded by shape and severity (grade 1 is 20 to 25% height loss, grade 2 is 25 to 40%, grade 3 is over 40%). Acute fractures cannot be dated reliably on radiographs.
• MRI (STIR sequence) shows bone marrow oedema in an acute fracture, and helps to exclude malignancy; CT shows retropulsion, cortical breaks and vacuum cleft.
• Dual energy X-ray absorptiometry (a vertebral fragility fracture alone confirms osteoporosis regardless of T-score).
• Blood tests for secondary causes: calcium (adjusted), phosphate, alkaline phosphatase, 25-hydroxyvitamin D, parathyroid hormone, creatinine and eGFR, full blood count, ESR, thyroid function, liver function, coeliac serology, serum protein electrophoresis with free light chains (myeloma), and testosterone in men. Bone turnover marker (serum CTX) if starting antiresorptive therapy.
• Biopsy only when imaging shows features of malignancy.

Differential diagnosis.

• Pathological fracture from metastasis or myeloma.
• Traumatic fracture, osteomyelitis and tuberculosis.
• Osteomalacia and Paget disease of bone.
• Degenerative disc disease, facet pain and renal colic.

The aims are to relieve pain quickly, restore mobility, correct the cause and prevent more fractures.

Acute pain (first weeks).

• Paracetamol 1 g orally every 6 hours (maximum 4 g daily; 3 g daily when weight is under 50 kg, with chronic alcohol use or hepatic impairment).
• Oral morphine 2.5 to 5 mg every 4 hours as needed in older adults (start low; titrate to 5 to 10 mg), or oxycodone 2.5 to 5 mg every 4 to 6 hours as needed, for up to 1 to 2 weeks.
• Monitor sedation, falls, constipation and respiration. Prescribe a laxative (macrogol 1 sachet once or twice daily or senna 7.5 to 15 mg at night).
• Short NSAID course (naproxen 500 mg orally every 12 hours with food, maximum 1000 mg daily, for up to 5 to 7 days) only if renal function and gastrointestinal and cardiovascular risk allow; add omeprazole 20 mg once daily.
• Calcitonin salmon 200 units intranasally once daily for 2 to 4 weeks reduces acute pain in some patients; avoid in malignancy risk and prolonged use; the effect is modest.
• Early mobilisation as pain permits; a soft or rigid brace for comfort may be used for a few weeks; avoid prolonged bed rest (accelerates bone loss).
• Physiotherapy: back extensor strengthening, posture training, balance and falls prevention, weight bearing exercise.

Vertebral augmentation (vertebroplasty or kyphoplasty). Considered for severe pain persisting beyond 4 to 6 weeks despite optimal analgesia, or for pain causing inability to mobilise or repeated hospital admission, with imaging showing a fresh fracture (oedema).

The evidence for benefit is mixed, with some studies showing faster pain relief and others no difference from sham procedure.

Risks: cement leakage (up to 30%, mostly asymptomatic), embolism, infection, adjacent fractures. Avoid with infection, coagulopathy, retropulsed fragments with neurological deficit, and painless fractures.

Surgery. For neurological deficit, unstable burst morphology, severe progressive kyphosis, or nonunion with instability: decompression and instrumented fusion with cement augmented screws.

Treatment of osteoporosis (start promptly after a vertebral fracture; the fracture indicates high or very high risk).

• Calcium: total intake 1000 to 1200 mg daily (diet first; supplement the difference), vitamin D 800 to 2000 units daily to reach a serum 25-hydroxyvitamin D of at least 50 nmol/L. Correct deficiency before starting zoledronic acid or denosumab (risk of hypocalcaemia).
• Alendronate 70 mg orally once weekly (with 200 mL of plain water on waking, upright for 30 minutes, 30 minutes before food or other drugs), or risedronate 35 mg once weekly.
• Avoid with oesophageal disorders, inability to sit upright, creatinine clearance under 35 mL/min, and hypocalcaemia.
• Zoledronic acid 5 mg intravenously over at least 15 minutes once yearly (hydrate; check creatinine clearance of at least 35 mL/min and calcium; acute phase reaction can be reduced with paracetamol); avoid within weeks of dental surgery.
• Denosumab 60 mg subcutaneously every 6 months (no renal limit but check calcium; do not stop without follow on treatment, as multiple vertebral fractures can follow within 12 months of a missed dose; give a bisphosphonate after stopping).
• Anabolic therapy for very high risk (recent or multiple vertebral fractures, very low T-score), followed by an antiresorptive:
  • Teriparatide 20 micrograms subcutaneously daily for up to 24 months.
  • Abaloparatide 80 micrograms subcutaneously daily for up to 24 months.
  • Romosozumab 210 mg subcutaneously once monthly for 12 months (avoid with myocardial infarction or stroke in the previous year).
• Avoid teriparatide and abaloparatide with Paget disease, prior skeletal radiotherapy, bone malignancy and hypercalcaemia.
• Bisphosphonate holidays and atypical femoral fracture and osteonecrosis of the jaw risks should be reviewed after 3 to 5 years of therapy; dental check before starting.
• Treat secondary causes (vitamin D deficiency, hyperparathyroidism, hypogonadism, malabsorption, glucocorticoid excess), and reduce glucocorticoid dose where possible.
• Falls prevention: review medicines (sedatives, antihypertensives), vision, footwear, home hazards, and balance training.

Operative antibiotic prophylaxis (augmentation or surgery). Cefazolin 2 g intravenously (3 g when weight is 120 kg or over) within 60 minutes before incision; with severe penicillin allergy, vancomycin 15 mg/kg intravenously starting 90 to 120 minutes before incision as a single dose.

Thromboprophylaxis for patients with limited mobility. Enoxaparin 40 mg subcutaneously once daily during immobility (20 mg at creatinine clearance under 30 mL/min), with mechanical measures.

Monitoring.

• Pain and function at 2 weeks, 6 weeks and 3 months.
• Repeat radiographs only if pain or kyphosis changes.
• Adherence and tolerance of osteoporosis treatment at 3 and 12 months.
• Bone density every 1 to 2 years (spine and hip).
• Calcium and creatinine before each zoledronic acid or denosumab dose.
• Height yearly.

Referral and escalation. Refer to bone health or metabolic bone clinic for fracture at age under 50, multiple fractures, secondary osteoporosis, or poor response. Urgent MRI and spinal referral for neurological symptoms, night pain with weight loss (suspect malignancy), fever, or pain unresponsive to analgesia. Emergency referral for cord or cauda equina syndrome.

Special groups.

• Men: investigate for hypogonadism, alcohol, glucocorticoids and myeloma.
• Glucocorticoid treated patients: alendronate or zoledronic acid; teriparatide for very high risk.
• Frail older adults: opioid doses start low; falls prevention and nutrition (protein 1.0 to 1.2 g/kg daily).
• Cancer patients on aromatase inhibitors or androgen deprivation: bone protective therapy and monitoring.
• Kidney impairment: avoid NSAIDs; adjust bisphosphonate choice (denosumab with calcium monitoring at creatinine clearance under 35 mL/min).