What is the appropriate treatment plan for a patient with a sacral fracture, potentially complicated by osteoporosis?

Treatment of Sacral Fractures

Initial Management Approach

For sacral fractures, treatment depends critically on fracture stability, displacement, and the presence of osteoporosis—stable, non-displaced fractures are managed conservatively with osteoporosis treatment and clinical monitoring, while displaced or unstable fractures require surgical fixation. 1, 2

Conservative Management for Stable Fractures

Most stable, non-displaced sacral insufficiency fractures in patients with osteoporosis should be managed non-operatively with immediate weight-bearing as tolerated, combined with aggressive osteoporosis treatment. 2, 3

• Patients are followed clinically until pain-free, then gradually increase activity in a controlled manner 1
• No additional imaging is typically needed once diagnosis is confirmed on radiographs or MRI, unless symptoms persist or complications develop 1
• Weight-bearing as tolerated should be allowed immediately, as this is standard practice for pelvic insufficiency fractures 2

Osteoporosis Treatment Protocol

Initiate oral bisphosphonate therapy (alendronate 70mg weekly) as first-line treatment immediately upon diagnosis, as this reduces vertebral fractures by 47-48%, non-vertebral fractures by 26-53%, and hip fractures by 51%. 2, 4

• Prescribe calcium 1000-1200mg daily and vitamin D 800 IU daily to reduce non-vertebral fractures by 15-20% and falls by 20% 2
• Order DXA scan of lumbar spine and hip to quantify bone mineral density 2
• Obtain laboratory workup to identify secondary causes of osteoporosis 2
• Implement supervised physical therapy with weight-bearing exercises to improve bone mineral density and muscle strength 2
• Conduct multidimensional fall risk assessment 2

Surgical Indications

Significantly displaced fractures, unstable pelvic ring injuries, or fractures with neurologic deficits require reduction and internal fixation. 5, 6, 3

Surgical fixation techniques include:

• Percutaneously placed iliosacral screws for stable fixation patterns 5, 3
• Posterior sacral "tension band" fixation for certain fracture configurations 5
• Lumbopelvic or triangular fixation for fracture patterns extending to the lumbar spine 5, 3
• Transsacral bar or screw fixation for bilateral instability 3
• Transiliac internal fixation for pelvic ring disruption 3

Sacroplasty Consideration

Sacroplasty is a safe, minimally invasive option for sacral insufficiency fractures that provides rapid and durable pain relief with low complication rates, particularly when conservative management fails. 7, 3

• Consider sacroplasty for patients with persistent severe pain despite conservative management 7, 3
• This technique is especially useful in osteoporotic patients who cannot tolerate prolonged immobilization 7

Monitoring for Complications

Patients with osteoporosis or those on bisphosphonate therapy are especially prone to progression of incomplete stress fractures to completion, requiring vigilant monitoring. 1

Red Flags Requiring Emergency Evaluation

Send patients to the emergency department immediately if any of the following develop 2:

• New neurological deficits (present in up to 50% of sacral fractures) 6
• Severe uncontrolled pain
• Signs of infection
• Hemodynamic instability (systolic BP <90 mmHg, shock index >1, or transfusion requirement of 4-6 units within 24 hours) 8, 9
• Evidence of new trauma with suspected acute fracture 2

Associated Injuries to Assess

Only 5% of sacral fractures occur in isolation—actively evaluate for pelvic ring disruptions, hip and lumbar spine fractures, neurologic injuries, and genitourinary trauma. 6

• Perform digital rectal examination to assess for high-riding or non-palpable prostate indicating urethral injury 9
• Inspect perineum and scrotum for hematoma, which suggests urethral injury occurring in 7-25% of pelvic ring fractures 9
• Check for blood at urethral meatus before catheter insertion 9
• Assess for hip dislocation requiring prompt reduction 9

Follow-Up Imaging Strategy

After initial diagnosis, additional imaging is typically unnecessary unless there is unexpected incomplete response to conservative therapy with return of symptoms. 1

• If symptoms persist or worsen, MRI without contrast is the preferred study to identify complications such as osteonecrosis, osteoid osteoma, or tumor 1
• CT without contrast can identify possible etiologies in delayed healing, such as completion of fracture 1
• Repeat radiographs in 10-14 days have increased sensitivity compared to initial films but are less sensitive than MRI 1

Critical Pitfalls to Avoid

• Do not rely solely on clinical examination, as sensitivity for spine fractures is only 81% 8, 9
• Do not dismiss vague pelvic pain in elderly patients as "arthritis" without imaging 8
• Do not assume isolated low back pain excludes sacral fracture, as presentation is often insidious 8
• In elderly or osteoporotic patients, bone scintigraphy abnormalities may not appear for several days post-injury 1
• Patients using corticosteroids may have less sensitive bone scintigraphy results 1
• Do not insert transurethral catheter without prior investigation if any signs of urethral injury are present 9

Special Considerations for Bisphosphonate Therapy

Monitor for atypical femoral fractures and osteonecrosis of the jaw in patients on long-term bisphosphonate therapy. 4

• Patients presenting with thigh or groin pain should be evaluated for atypical femur fracture 4
• For patients requiring invasive dental procedures, consider discontinuation of bisphosphonate therapy to reduce ONJ risk 4
• Severe bone, joint, or muscle pain may develop; discontinue if severe symptoms occur 4
• Alendronate is not recommended for patients with creatinine clearance less than 35 mL/min 4