What is the best imaging modality for anterior hip pain?

Best Imaging for Anterior Hip Pain

Plain radiographs (anteroposterior pelvis view plus frog-leg lateral view of the symptomatic hip) should be obtained first in essentially all cases of anterior hip pain, followed by MRI without IV contrast if radiographs are negative, equivocal, or nondiagnostic. 1, 2

Initial Imaging: Plain Radiographs

• Radiographs are the mandatory first test for anterior hip pain, providing excellent screening for common disorders like osteoarthritis, fractures, dysplasia, femoroacetabular impingement, and bone tumors 1, 3
• The complete radiographic evaluation must include both an AP view of the pelvis AND a frog-leg lateral view of the symptomatic hip 2, 3
• Specialized views (false profile or Dunn view) can provide additional detail for suspected dysplasia or femoroacetabular impingement 1
• Common pitfall: Obtaining only a single hip view rather than both pelvis and hip views may miss critical pathology 2

Second-Line Imaging After Negative/Equivocal Radiographs

The choice of advanced imaging depends on the suspected pathology based on clinical presentation:

For Suspected Intra-Articular Pathology (Labral Tears, Impingement)

• MR arthrography is the gold standard (rated 9/9 "usually appropriate") for suspected labral tears with or without femoroacetabular impingement 1, 2
• CT arthrography is an acceptable alternative (rated 7/9) if MRI is contraindicated 1
• Standard MRI without IV contrast is moderately appropriate (rated 6/9) but less sensitive than MR arthrography for labral pathology 1
• Diagnostic injection can be performed simultaneously with arthrography to confirm the hip joint as the pain source (rated 5/9) 1

For Suspected Extra-Articular Soft Tissue Pathology

• MRI without IV contrast is the preferred test (rated 9/9) for suspected tendonitis, bursitis, or muscle injuries 1, 2
• Ultrasound is a valuable alternative (rated 7/9) for superficial structures like iliopsoas tendon, hip flexor injuries, or trochanteric bursitis 1, 4
• MRI excels at detecting iliopsoas bursitis, subiliacus bursitis, athletic pubalgia, abductor tendinosis/tears, and hamstring injuries 1

For Articular Cartilage Evaluation

• Both MRI without IV contrast AND MR arthrography are equally appropriate (both rated 9/9) for evaluating articular cartilage 1
• CT arthrography is also highly appropriate (rated 8/9) and may be superior to MRI for detecting chondral lesions in some studies 1

Special Considerations for Anterior Hip Pain

When Referred Pain is Suspected

• If lumbar spine, sacroiliac joint, or knee pathology could be contributing, MRI of the hip without IV contrast (rated 9/9) should be performed to exclude hip pathology as the source 2
• Consider lumbar spine imaging if clinical suspicion points to radiculopathy or referred pain 2, 3
• Image-guided diagnostic hip injection (rated 8/9) can definitively determine if the hip joint is the pain source when multiple potential etiologies exist 2

Imaging Modalities to Avoid Initially

• CT without contrast, bone scans, and PET scans are rated 1/9 ("usually not appropriate") for initial evaluation of anterior hip pain 1
• IV contrast (without arthrography) does not improve diagnostic yield for most hip pathology 1

Clinical Decision Algorithm

1. Always start with plain radiographs (AP pelvis + frog-leg lateral) 1, 2, 3
2. If radiographs show osteoarthritis and clinical picture matches, no further imaging may be needed 1
3. If radiographs are negative/equivocal:
   • Suspect labral tear/impingement → MR arthrography 1, 2
   • Suspect soft tissue injury (tendonitis, bursitis) → MRI without contrast or ultrasound 1, 2
   • Suspect cartilage damage → MRI without contrast or MR arthrography 1
   • Uncertain diagnosis with multiple potential sources → MRI without contrast + consider diagnostic injection 2

Critical pitfall: Proceeding directly to advanced imaging without obtaining plain radiographs first is not recommended and may miss obvious pathology visible on simple X-rays 1, 2