What is the most likely diagnosis in a 69-year-old woman who fell onto her buttocks two days ago and now has severe right hip pain radiating to the lateral thigh, with ability to move both legs while supine but intolerable pain on standing?

Most Likely Diagnosis: Proximal Femoral Fracture (Hip Fracture)

This 69-year-old woman most likely has a proximal femoral fracture—either a femoral neck fracture or an intertrochanteric fracture—that may be occult on initial radiographs. The classic presentation of severe pain on weight-bearing despite preserved supine leg movement after a ground-level fall in an elderly woman is pathognomonic for hip fracture, even when initial imaging appears negative 1.

Clinical Reasoning

The ability to move both legs while supine does not exclude a serious fracture. Patients with basicervical and minimally displaced femoral neck fractures can maintain range of motion and even some weight-bearing ability initially 2. The key diagnostic feature here is the severe pain on standing—this represents mechanical instability that becomes symptomatic only under axial loading 1, 3.

Why Hip Fracture is Most Likely:

• Demographics: 69-year-old woman—hip fractures are nearly twice as common in women as men, with elderly osteoporotic patients at highest risk 1
• Mechanism: Ground-level fall onto buttocks is the typical mechanism for proximal femoral fractures in this population 1
• Pain pattern: Right hip pain radiating down the lateral thigh is consistent with referred pain from hip pathology 4
• Functional limitation: Severe pain on standing with preserved supine movement is the hallmark of mechanical hip fracture instability 1, 3

Immediate Diagnostic Approach

Obtain AP pelvis and cross-table lateral hip radiographs immediately as first-line imaging 1, 3. Standard views include an AP view with 15 degrees of internal rotation and a cross-table lateral view (not frog-leg lateral, which risks fracture displacement) 1.

If Radiographs are Negative or Equivocal:

Proceed immediately to CT hip without IV contrast—do not wait or repeat plain films 3. The American College of Radiology demonstrates that CT detects occult hip fractures in 24.1% of patients with negative radiographs and changes management in 20% of cases, with 94% sensitivity and 100% specificity 3.

Critical pitfall to avoid: Do not rely on clinical examination alone to exclude fracture. Hip fractures cannot be diagnosed or excluded definitively via physical examination 1. Do not increase the number of radiographic projections instead of proceeding to CT—this does not decrease the need for cross-sectional imaging 3.

Alternative if CT Unavailable:

MRI without contrast can detect occult hip fractures with high sensitivity. In a prospective study of 100 patients with negative radiographs and persistent clinical suspicion, MRI identified femoral neck or intertrochanteric fractures in 46% of cases 5.

Differential Considerations

While hip fracture is most likely, the differential includes:

• Pelvic fractures (sacrum, pubic rami)—often coexist with hip fractures, which is why AP pelvis view is essential 1
• Greater trochanter avulsion fracture—may be managed non-operatively if no femoral neck extension 3
• Hip dislocation—extremely unlikely without high-energy trauma in this age group 1

Urgency and Management Implications

This patient requires urgent orthopedic surgical consultation and hospital admission 2. Delays in diagnosis and treatment are associated with increased mortality—surgical delay beyond 12 hours significantly increases 30-day mortality risk 1. The 1-year mortality rate for hip fractures is 22% for women and 33% for men 1.

Immediate Actions While Awaiting Imaging:

• Implement multimodal analgesia including peripheral nerve block (iliofascial block) 1
• Do not use preoperative traction—this is contraindicated 1
• Keep patient non-weight-bearing until fracture is excluded 3
• Obtain CBC, basic metabolic panel, and ECG for preoperative clearance 2

If Fracture Confirmed:

• Surgery should occur within 24-48 hours 2
• Cemented femoral stem is recommended for arthroplasty 1, 2
• Administer tranexamic acid intraoperatively 1, 2
• Initiate VTE prophylaxis and continue for 4 weeks postoperatively 1, 2
• Refer to Bone Health Clinic for osteoporosis evaluation and secondary fracture prevention 1, 2