Diagnostic Approach to Severe Hip Pain After Trauma with Negative X-ray

Immediate Priority: Rule Out Occult Fracture

The American College of Radiology recommends obtaining CT hip without IV contrast as the next imaging study if rapid diagnosis is needed, or MRI hip without IV contrast if time permits and comprehensive soft tissue evaluation is desired, as 39% of patients with negative radiographs but clinical suspicion have surgical hip fractures 1, 2
CT detects occult fractures in 24.1% of cases with negative X-rays and changes management in 20%, with a sensitivity of 94% and specificity of 100% for occult hip fractures 1
MRI approaches 100% sensitivity for fracture detection, making it a valuable tool for diagnosing occult hip fractures 3
Delayed diagnosis increases risk of osteonecrosis and prolonged immobility, emphasizing the importance of prompt advanced imaging 1, 2

Nondisplaced femoral neck fractures are the most common occult fracture, highlighting the need for careful evaluation of the femoral neck in patients with severe hip pain after trauma 3
Intertrochanteric fractures with radiographically occult extension are also a concern, as isolated greater trochanter fractures on X-ray frequently have intertrochanteric extension on MRI 3

Soft tissue injuries, including muscle/tendon tears, trochanteric bursitis, and iliopsoas tendinopathy or bursitis, are highly prevalent in trauma patients with negative radiographs and should be evaluated with MRI without contrast 4, 5
Nerve compression/injury, such as obturator nerve compression, lateral femoral cutaneous nerve injury, and sciatic nerve compression, should be considered if numbness or radiating pain is present 4
Referred pain sources, including lumbar radiculopathy, lumbar facet arthropathy, and sacroiliac joint dysfunction, must be evaluated if hip imaging is unrevealing 4

If excruciating pain persists after negative X-ray, obtain CT hip without IV contrast immediately or MRI hip without IV contrast, as recommended by the American College of Radiology 1, 2
If CT is negative but clinical suspicion remains high, proceed to MRI, as CT has 50 documented false-negatives in meta-analysis 1

Never assume negative X-ray excludes fracture in trauma patients with severe persistent pain, as up to 39% have occult fractures, according to the American College of Radiology 1
Do not delay advanced imaging beyond 2-3 days if pain worsens, as occult fractures may require urgent surgical intervention 4

Acetaminophen is non-inferior to NSAIDs for minor musculoskeletal trauma and may be safer, particularly if patient has cardiovascular risk factors or is elderly, as recommended by the World Journal of Emergency Surgery 6, 7