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, neurologic status, and whether the fracture is traumatic versus insufficiency-related; most stable, non-displaced insufficiency fractures are managed conservatively with osteoporosis treatment and clinical monitoring, while displaced or unstable fractures require surgical fixation. 1, 2

Immediate Assessment Requirements

Before determining treatment, you must establish:

• Hemodynamic stability: Document systolic BP <90 mmHg, shock index >1, or transfusion requirements of 4-6 units within 24 hours, as sacral fractures are among the principal injuries causing hemodynamic instability in pelvic trauma 3, 4
• Neurologic status: Up to 50% of sacral fractures have associated neurologic injuries that dictate surgical urgency 5
• Fracture displacement and stability: Only 5% of sacral fractures occur in isolation; assess for pelvic ring disruptions, lumbar spine fractures, and hip injuries 5
• Associated injuries: Check for urethral injury (7-25% incidence), active bleeding, and open fractures 4, 5

Treatment Algorithm by Fracture Type

Insufficiency Fractures (Osteoporosis-Related)

Conservative management is appropriate when radiographic findings are conclusive for insufficiency fracture with stable vital signs, no displacement progression, and no neurological deficits. 6

Non-operative Protocol:

• Weight-bearing as tolerated immediately - standard for sacral and pubic rami insufficiency fractures 6
• Clinical monitoring until pain-free, then gradual activity increase 1
• No additional imaging required after diagnosis is confirmed on initial studies 1

Osteoporosis Treatment (Essential Component):

• Initiate oral bisphosphonate therapy (e.g., alendronate) as first-line treatment, which reduces vertebral fractures by 47-48%, non-vertebral fractures by 26-53%, and hip fractures by 51% 6, 7
• Order DXA scan of lumbar spine and hip to quantify bone mineral density 6
• Prescribe calcium 1000-1200mg daily and vitamin D 800 IU daily, reducing non-vertebral fractures by 15-20% and falls by 20% 6
• Implement supervised physical therapy with weight-bearing exercises to improve bone mineral density and muscle strength 6

Critical pitfall: Patients with osteoporosis or on bisphosphonate therapy are prone to progression of incomplete stress fractures to completion, requiring closer monitoring 1

High-Energy Traumatic Fractures

Stable, Non-displaced Fractures:

• Non-operative management with protected weight-bearing and clinical follow-up 8, 2
• No routine follow-up imaging unless symptoms persist or worsen 1

Displaced or Unstable Fractures:

Surgical fixation is required for significantly displaced fractures, pelvic ring instability, or progressive neurologic deficits. 8, 2

Surgical options include:

• Percutaneous iliosacral screws for vertically oriented fractures 8, 2
• Posterior sacral tension band fixation for transverse patterns 8
• Lumbopelvic or triangular fixation for fractures extending to lumbar spine 8, 2
• Transsacral bar or transiliac internal fixation for severe instability 2

Sacroplasty Consideration

Sacroplasty is a safe, minimally invasive option providing rapid and durable pain relief for insufficiency fractures failing conservative management. 9, 2

Indications:

• Severe, persistent pain despite 4-6 weeks of conservative treatment 2
• Fracture without significant displacement or neurologic compromise 9, 2
• Low complication incidence compared to open surgical approaches 9

Follow-up and Monitoring

Clinical Follow-up Protocol:

• Monitor clinically until pain-free, typically without additional imaging 1
• If symptoms return with increased activity, perform follow-up imaging to assess for fracture completion or delayed healing 1
• MRI is preferred over CT or bone scan for evaluating complications like osteonecrosis or delayed healing 1

Red Flags Requiring Emergency Evaluation:

• New neurological deficits developing after initial assessment 6
• Severe uncontrolled pain despite appropriate analgesia 6
• Signs of infection or wound complications 6
• Hemodynamic instability or evidence of new trauma 6

Special Populations

Pregnant Patients:

• Pregnancy-related sacral fractures are rare but occur in third trimester or postpartum 1
• MRI without contrast is preferred for diagnosis to avoid ionizing radiation 1
• Management is similar to age-related insufficiency fractures, with conservative treatment and activity modification 1

Elderly/Osteoporotic Patients:

• High index of suspicion required as presentation is often insidious with vague pelvic or lower back pain 1, 2
• Radiographs may be initially negative due to overlying soft tissue and sacral curvature; MRI is more sensitive 1, 2
• Bone scintigraphy may be falsely negative for several days post-injury in elderly or corticosteroid users 1

Critical Pitfalls to Avoid

• Do not dismiss vague pelvic pain in elderly patients as "arthritis" without imaging, as insufficiency fractures have insidious onset 3
• Do not rely solely on clinical examination, which has only 81% sensitivity for spine fractures 3, 4
• Do not overlook the "Honda sign" absence on bone scan - only 63% of sacral insufficiency fractures demonstrate this finding 1
• Do not delay MRI in high-risk patients (osteoporosis, bisphosphonate therapy, athletes) as fracture completion risk is elevated 1
• Do not insert urethral catheter without prior investigation if blood at meatus or perineal hematoma present 4