Left Hip Pain Radiating to Leg: Diagnostic and Treatment Approach
Initial Imaging
Start with plain radiographs of both the pelvis (AP view) and symptomatic hip (frog-leg lateral view) as your first imaging test. 1
- Radiographs serve as an excellent screening tool to identify fractures, arthritis, and bone tumors 1
- Failing to obtain both pelvis and hip views may miss important pathology 1
- Proceeding directly to advanced imaging without plain radiographs is not recommended 1
Localization of Pain Source
The anatomic location of pain guides your differential diagnosis:
- Anterior hip/groin pain suggests intra-articular pathology (labral tears, femoroacetabular impingement, osteoarthritis) 2, 3
- Lateral hip pain most commonly indicates greater trochanteric pain syndrome (gluteus medius tendinopathy, bursitis, iliotibial band friction) 2
- Posterior hip pain with leg radiation suggests lumbar spinal pathology, deep gluteal syndrome with sciatic nerve entrapment, or hamstring tendinopathy 2
Next Steps Based on Initial Radiographs
If Radiographs Are Negative or Equivocal:
Order MRI of the hip without IV contrast (rated 9/9 appropriateness by ACR). 1
- MRI detects soft tissue abnormalities including tendonitis, bursitis, muscle/tendon tears, and nerve compression that could explain radiating symptoms 1
- MRI identifies occult fractures not visible on plain films, particularly stress fractures 1
- MRI evaluates labral tears, though MR arthrography is superior if this is specifically suspected 1
If Lumbar Spine Pathology Is Suspected:
Consider lumbar spine MRI in addition to hip imaging when clinical suspicion exists for referred pain from spine pathology. 1
- Posterior hip pain with leg radiation frequently represents lumbar disc or facet joint disease 4
- When both hip and spine pathology are suspected, perform MRI of the hip first to exclude hip pathology 1
Diagnostic Injections for Confirmation
Use image-guided intra-articular hip injection (rated 8/9 appropriateness) to determine if pain originates from the hip joint versus surrounding structures or referred sources. 1
- Diagnostic joint injections are safe and useful for confirming the etiology of pain 5
- Injections can provide both diagnostic information and therapeutic benefit 1
- Ultrasound-guided anesthetic injections aid in diagnosing intra-articular causes 2
- Avoid peripheral nerve blocks of the obturator nerve, which are experimental/investigational due to insufficient evidence 1
Advanced Imaging for Specific Diagnoses
For Suspected Labral Tear or Femoroacetabular Impingement:
MR arthrography is the preferred diagnostic test. 1, 3
- CT arthrography is an acceptable alternative 1
- Standard MRI can evaluate labral tears but is less sensitive than MR arthrography 1
What NOT to Do:
Do not order nuclear medicine bone scan, PET imaging, or CT without contrast for this presentation (rated 1/9 appropriateness). 1
- These modalities inadequately evaluate soft tissue pathology causing radiating symptoms 1
- They expose patients to unnecessary radiation and provide less diagnostic information than MRI 1
Treatment Considerations Based on Diagnosis
Intra-articular Pathology:
- Femoroacetabular impingement, labral tears, and gluteus medius tendon tears typically have good surgical outcomes, so early referral may improve outcomes 2
Greater Trochanteric Pain Syndrome:
- Most common cause of lateral hip pain after osteoarthritis 4
- Responds to conservative management in many cases 2
Referred Pain from Spine:
Critical Pitfalls to Avoid
- Occult femoral neck fractures can present with normal initial radiographs and require MRI for diagnosis 1
- Delaying MRI if pain worsens or persists beyond 2-3 days may indicate an occult fracture requiring urgent surgical intervention 1
- Do not proceed directly to MR arthrography unless there is specific clinical suspicion for labral tear or femoroacetabular impingement 1
- Ultrasound is inferior to MRI for comprehensive evaluation of intra-articular pathology and occult fractures 1