Is an ultrasound a useful diagnostic tool for a patient with continual hamstring pain?

Ultrasound for Hamstring Pain: Limited Diagnostic Utility

Ultrasound has limited usefulness for diagnosing hamstring injuries and should not be the primary imaging modality—MRI without contrast is the definitive diagnostic test with near-perfect detection rates and should be obtained when imaging is warranted. 1

Why MRI is Superior to Ultrasound

MRI without contrast is the gold standard for hamstring injury diagnosis, achieving a 100% detection rate for proximal hamstring avulsions compared to ultrasound's limited 58.3% detection rate. 1 This dramatic difference in sensitivity is clinically significant because:

• MRI provides comprehensive assessment of injury location, extent, degree (partial versus complete), and chronicity—all critical factors for treatment planning and return-to-play decisions 1
• MRI identifies associated injuries that ultrasound cannot detect, including deep soft-tissue pathology 1
• MRI excels at evaluating proximal hamstring injuries, which are particularly important to diagnose accurately as they often require prolonged healing and may need surgical intervention 1, 2

When Ultrasound Has Any Role

Ultrasound does have limited utility in specific contexts:

• Initial screening in experienced hands: Recent research shows ultrasound can detect muscle damage around the hamstring origin tendon with high detection rates, making it potentially useful for initial evaluation before proceeding to definitive MRI 3
• Guided interventions: Ultrasound is valuable for guiding therapeutic injections into the hamstring tendon 4
• Not for definitive diagnosis: Even when ultrasound detects abnormalities, MRI should still be obtained as the final diagnostic tool 3

Clinical Approach Algorithm

For a patient with continual hamstring pain, follow this sequence:

1. Clinical examination first: Focus on posterior thigh pain location, palpable tenderness, and functional testing with maneuvers that simulate hamstring loading 1

2. Proceed directly to MRI without contrast when imaging is warranted based on clinical findings—this is the American Academy of Family Physicians' recommended approach 1

3. Skip ultrasound as a diagnostic step unless MRI is unavailable or contraindicated, as it will likely require MRI confirmation anyway 1, 3

Critical Pitfalls to Avoid

• Do not rely on ultrasound alone for treatment decisions, especially for proximal hamstring injuries where the miss rate exceeds 40% 1
• Do not delay MRI in favor of attempting ultrasound first—this only postpones definitive diagnosis 1
• Recognize that "continual" pain suggests chronic pathology that requires the comprehensive assessment only MRI can provide for surgical planning if conservative management fails 1, 2

The evidence is unequivocal: while ultrasound may detect some hamstring pathology, MRI without contrast remains the mainstay for evaluating hamstring injuries with superior sensitivity, specificity, and clinical utility for guiding treatment decisions. 1, 5, 2