What radiographic imaging is recommended for hip pain radiating down the leg?

Radiographic Imaging for Hip Pain Radiating Down the Leg

For hip pain radiating down the leg, plain radiographs of both the pelvis and hip should be obtained first, followed by MRI if radiographs are negative or equivocal. 1

Initial Imaging Approach

• Plain radiographs (X-rays) of both the pelvis and hip should be the first imaging test for all patients with hip pain radiating down the leg 1
• A complete radiographic evaluation should include:
  • Anteroposterior (AP) view of the pelvis 1
  • Frog-leg lateral view of the symptomatic hip 1, 2
• Radiographs serve as an excellent screening tool to identify common disorders such as arthritis, fractures, and bone tumors 1
• For many disorders, viewing both the pelvis and proximal femur provides more diagnostic information than radiographs limited to the ipsilateral hip 1

Secondary Imaging Based on Initial Radiograph Results

If Radiographs Are Negative, Equivocal, or Nondiagnostic:

1. For suspected soft tissue abnormality (tendinitis, bursitis):

   • MRI hip without IV contrast (first choice) 1
   • Ultrasound (US) is a valuable alternative, particularly for evaluating superficial structures like abductor tendons, trochanteric bursitis, or snapping hip syndrome 1

2. For suspected nerve compression or radiating pain:

   • MRI of the hip without IV contrast 1
   • Consider lumbar spine imaging if clinical suspicion of referred pain from spine pathology 1, 3
   • Note that disk space narrowing at L1/L2 and L2/L3 levels has been significantly associated with hip pain radiating to the leg 3

3. For suspected labral tear or femoroacetabular impingement:

   • MR arthrography is the preferred method 1, 2
   • CT arthrography is an acceptable alternative 1

Special Considerations

• Hip pain radiating down the leg may represent referred pain from the lumbar spine, particularly from upper lumbar disk degeneration (L1/L2, L2/L3) 3
• When both hip and spine pathology are suspected, MRI of the hip without IV contrast should be performed to exclude hip pathology 1
• Diagnostic injections (image-guided anesthetic with or without corticosteroid) can help determine if pain is originating from the hip joint or surrounding structures 1

Common Pitfalls to Avoid

• Failing to obtain both pelvis and hip views, which may miss important pathology 1
• Attributing hip pain radiating down the leg solely to hip pathology without considering lumbar spine pathology 3, 4
• Proceeding directly to advanced imaging without first obtaining plain radiographs 1
• Overlooking rare but serious causes of hip pain radiating to the leg, such as tumors or infections, which may require additional imaging beyond the standard protocol 4, 5

Algorithm for Imaging Selection

1. Obtain plain radiographs (pelvis AP and hip frog-leg lateral views)
2. If radiographs show clear pathology (e.g., advanced osteoarthritis), treat accordingly
3. If radiographs are negative or equivocal:
   • For suspected soft tissue pathology: MRI without contrast or ultrasound
   • For suspected labral tear/impingement: MR arthrography
   • For suspected referred pain: Consider additional lumbar spine imaging
4. Consider diagnostic injections to confirm the pain source when diagnosis remains unclear after imaging 1