Clues Pointing TO This Diagnosis

82-year-old woman living alone — the classic demographic, as the mean age at hip fracture is about 81 and incidence is higher in women
Ground-level fall onto the hip — most hip fractures occur after a simple fall from standing height in older adults
Right leg shortened and externally rotated — the hallmark deformity of a displaced proximal femur fracture
Inability to bear weight after the fall — a cardinal sign of hip fracture
Known osteoporosis — thin, fragile bone is the underlying substrate for a fragility fracture
Femoral neck location on X-ray — femoral neck fractures account for about 34% of hip fractures and are the classic intracapsular pattern
Prior unsteadiness/gait instability over the past year — a documented fall-risk factor preceding the injury
Advanced age as a risk factor — hip fracture risk roughly doubles every 5 years after age 50
Fragility (low-energy) mechanism — a break from a fall from standing height defines an osteoporotic fragility fracture

Why It's NOT the Similar Diseases

NOT hip osteoarthritis — arthritis causes chronic activity-related groin pain and stiffness, not an acute post-fall inability to bear weight with a shortened, externally rotated limb
NOT lumbar radiculopathy — nerve-root pain radiates down the leg in a dermatomal pattern without limb shortening/external rotation or a fracture line on X-ray
NOT hip dislocation — a native hip dislocation is rare without a prosthesis and classically produces a flexed, adducted, internally rotated limb rather than the shortened, externally rotated position seen here
NOT isolated soft-tissue contusion — a contusion allows some weight-bearing and shows no radiographic fracture, whereas she cannot bear weight and has a visible fracture
NOT pathologic fracture from metastasis — the story describes low-energy trauma with known osteoporosis rather than an atraumatic break or a destructive bony lesion

Differential Diagnosis List

Hip osteoarthritis — ruled out by acute post-fall onset with limb shortening/external rotation and a fracture on imaging
Lumbar radiculopathy — ruled out by absence of dermatomal radiating pain and presence of a femoral neck fracture
Hip dislocation — ruled out by the shortened, externally rotated position and radiographic fracture rather than an empty acetabulum
Soft-tissue contusion/muscle strain — ruled out by inability to bear weight and a visible fracture line
Pathologic (metastatic) fracture — ruled out by low-energy fragility mechanism in a patient with known osteoporosis and no destructive lesion

Key Distinguishing Test

A plain anteroposterior pelvis and hip radiograph is the first-line confirmatory test and typically demonstrates the femoral neck fracture. When the film is normal but suspicion remains (occult fracture), MRI is the most sensitive study to confirm the diagnosis.

Board Note

Classify by location: intracapsular femoral neck fractures risk disrupting the femoral head blood supply (avascular necrosis), so displaced femoral neck fractures in older adults are usually treated with arthroplasty (hemiarthroplasty, or total hip arthroplasty in active independent ambulators), whereas nondisplaced neck and extracapsular intertrochanteric fractures are typically fixed with internal fixation
Guidelines recommend surgery within about 24–48 hours, which is associated with lower mortality and fewer complications
Hip fracture carries a 1-year mortality of roughly 22%–30%; leading causes of death include pneumonia, pulmonary embolism, myocardial infarction, and sepsis
Prevent VTE (asymptomatic DVT occurs in up to ~50%) with pharmacologic prophylaxis (LMWH, a DOAC, or aspirin) typically continued up to ~35 days, and mobilize/weight-bear as tolerated on postoperative day 1
Treat the underlying osteoporosis as secondary fracture prevention with an antiresorptive (bisphosphonate or denosumab) plus calcium and vitamin D, and implement fall-prevention measures (grab bars, non-slip mats, lighting, balance training); a fracture liaison service improves treatment initiation and adherence
Postoperative transfusion threshold in asymptomatic hip fracture patients is a hemoglobin below 8 g/dL

“Minerva’s Story”