What X-ray (radiograph) is recommended for an elderly patient with a history of osteoporosis and potential bleeding disorders who has fallen straight down onto their buttock in a nursing home setting?

Imaging for Elderly Nursing Home Patient with Fall onto Buttock

Order an AP pelvis X-ray immediately as the first-line imaging study, but recognize that if pain persists or limits mobilization, you must obtain a CT pelvis without contrast because plain radiographs miss 70% of posterior pelvic ring fractures (sacrum and ilium) in elderly patients. 1, 2, 3

Initial Imaging Approach

Start with AP Pelvis Radiograph

• Obtain AP pelvis and lateral views as the initial screening examination because radiographs are rapidly obtained, well-tolerated, and can identify obvious fractures if present 1
• However, understand that plain pelvic X-rays have only 10.5% sensitivity for detecting sacral fractures in elderly patients due to overlying bowel gas, fecal material, vascular calcifications, and soft tissue 1, 3
• In elderly osteoporotic patients, radiographs are particularly insensitive and may remain negative even when fractures are present 1

Critical Pitfall to Avoid

• Do not assume normal X-rays exclude injury - plain radiographs miss 21.7-24.1% of pelvic fractures in elderly patients, particularly posterior ring injuries 2, 3
• A fall directly onto the buttock creates a high-energy vertical shear force through the pelvis, making sacral and pubic rami fractures highly likely even with "normal" initial films 1, 2

When to Proceed to Advanced Imaging

Obtain CT Pelvis Without Contrast If:

• Pain substantially limits mobilization or weight-bearing - this indicates potential instability requiring surgical consideration 1, 2
• Clinical suspicion remains high despite negative radiographs - elderly patients with osteoporosis and fall mechanism warrant CT 1
• Patient has persistent pain at 1-2 week follow-up - this suggests occult fracture 1, 4

Why CT Over MRI in This Population:

• CT has 94% sensitivity and 100% specificity for pelvic fractures and is just as effective as MRI for detecting fractures 4
• CT reduces ED time by 72 minutes compared to MRI (430 vs 502 minutes average) 4
• 26% of elderly patients have contraindications to MRI (pacemakers, metal implants, claustrophobia) 4
• CT is superior for evaluating the sacrum and pelvis because it selectively samples bone and excludes overlying soft tissue 1

Specific Fracture Patterns to Anticipate

Posterior Pelvic Ring Injuries (Most Commonly Missed)

• 70% of elderly patients with pubic rami fractures visible on X-ray have an associated occult posterior ring injury (sacrum or ilium) that only CT can detect 2
• Sacral insufficiency fractures occur at predictable sites and may present with intractable lower back or pelvic pain with loss of mobility 1
• 88% of sacral fracture patients are female with average age 85 years 3

Anterior Ring Injuries

• 75% of sacral fractures are accompanied by pubic rami fractures 3
• Isolated anterior ring fractures are biomechanically stable and less painful, but combined anterior-posterior injuries cause instability requiring different treatment 2

Clinical Decision Algorithm

If radiographs show obvious fracture:

• No further imaging needed for diagnosis 1
• Proceed to orthopedic consultation and surgical planning 5, 6

If radiographs are negative but patient cannot mobilize due to pain:

• Obtain CT pelvis without contrast immediately 1, 2, 4, 3
• Do not wait for "clinical follow-up" - delayed diagnosis increases mortality and complications 5, 6

If radiographs are negative and patient can mobilize with mild pain:

• Trial of conservative management with weight-bearing as tolerated 7
• Repeat clinical evaluation at 1-2 weeks - if pain persists or worsens, obtain CT 1, 7

Immediate Concurrent Management

While arranging imaging, simultaneously:

• Activate interdisciplinary orthogeriatric consultation to optimize comorbidities and reduce complications 5, 6
• Implement multimodal analgesia with acetaminophen and consider peripheral nerve block, minimizing opioids to prevent delirium 5
• Obtain CBC, BMP, ECG as part of preoperative workup 5, 6
• Do not prescribe bed rest - immobility increases mortality; allow weight-bearing as tolerated even before definitive diagnosis 7

Why This Matters for Outcomes

• Surgery within 24-48 hours reduces mortality in elderly hip and pelvic fractures 5, 6
• Undiagnosed posterior ring injuries cause prolonged immobilization, leading to pressure ulcers, pneumonia, deconditioning, and death 8, 2
• Elderly patients with bleeding disorders on anticoagulation require urgent fracture identification to guide reversal decisions and surgical timing 5