For a suspected tear of the superficial hip muscles (gluteus medius/minimus), should the initial imaging be an ultrasound or an MRI?

MRI Should Be the Initial Advanced Imaging for Suspected Hip Muscle Tears

For suspected tears of the gluteus medius or minimus muscles, MRI without contrast is the appropriate initial imaging modality after plain radiographs, not ultrasound. 1, 2

Algorithmic Approach to Imaging

Step 1: Obtain Plain Radiographs First

• Standard AP and lateral hip radiographs should be obtained initially to exclude bony pathology, fractures, or other structural abnormalities before proceeding to advanced imaging. 1, 2, 3

Step 2: Proceed Directly to MRI (Not Ultrasound)

• The American College of Radiology explicitly states there is insufficient evidence to support ultrasound as the next imaging study for evaluation of suspected tendon, muscle, or ligament injury. 1
• Non-contrast MRI of the hip is the definitive imaging study with sensitivity ranging from 33-100% and specificity of 92-100% for detecting gluteus medius/minimus tendon tears. 1, 2, 3
• MRI achieved 91% accuracy with 73% sensitivity and 95% specificity in detecting these tears. 4

Why MRI Outperforms Ultrasound

Superior Detection Rates

• In direct comparison studies, MRI detected 100% of proximal muscle-tendon injuries while ultrasound detected only 58.3%. 1, 2
• Ultrasound has demonstrated only 79% sensitivity for gluteus medius/minimus tears in patients with chronic greater trochanteric pain syndrome. 1, 2

Comprehensive Assessment Capabilities

• MRI provides complete evaluation of all peritrochanteric structures including the gluteus medius and minimus muscles, abductor tendons, and trochanteric bursa. 1, 2
• MRI can classify the location, extent, degree (partial versus complete), and chronicity of tendon injuries—critical information for surgical decision-making. 1, 2
• MRI can identify associated pathology including iliofemoral ligament and ligamentum teres injuries that may contribute to hip pain. 1, 2

Clinical Decision-Making

• MRI has limited use in return-to-play decisions for athletes, whereas ultrasound provides even less utility in this context. 1, 2
• MRI can assess tear size, retraction, and fatty degeneration—factors that determine whether early surgical repair (within 3 weeks to 3 months) is indicated. 3

Critical Pitfalls to Avoid

Don't Skip Plain Films

• Always obtain radiographs first to rule out obvious bony abnormalities before ordering MRI. 1, 2, 3

Don't Use Ultrasound as Primary Diagnostic Tool

• While ultrasound can detect trochanteric bursitis and some tendon pathology, it is difficult to distinguish between gluteus medius tendinosis and bursitis on ultrasound. 2, 5
• Reserve ultrasound primarily for guided interventions (such as corticosteroid injections) rather than as a primary diagnostic tool. 2

Don't Delay Imaging in Acute Presentations

• In acute full-thickness tears, early diagnosis via MRI is essential because surgical repair within 3 weeks produces superior outcomes compared to delayed repair. 3
• Delayed diagnosis leads to tendon retraction and fatty degeneration, which worsen surgical outcomes. 3

Special Consideration for Hip Prostheses

• In patients with hip prostheses, MRI is superior for identifying extracapsular disease associated with adverse reactions to metal debris that could be misinterpreted as trochanteric bursitis. 2, 5

When Ultrasound Has Limited Role

Ultrasound may be considered only for:

• Guiding therapeutic corticosteroid injections into the peritrochanteric space (not for primary diagnosis). 2, 5
• Detecting trochanteric bursitis when that is the primary clinical suspicion, though differentiation from tendinosis remains challenging. 5