What is the preferred imaging modality, ultrasound or MRI (Magnetic Resonance Imaging), for diagnosing gluteus medius tendon pathology and greater trochanteric pain syndrome?

MRI is Superior to Ultrasound for Diagnosing Gluteus Medius Tendon Pathology and Greater Trochanteric Pain Syndrome

MRI without contrast is the preferred imaging modality for diagnosing gluteus medius tendon pathology and greater trochanteric pain syndrome due to its superior diagnostic accuracy compared to ultrasound. 1

Diagnostic Accuracy Comparison

• MRI remains the mainstay for evaluating gluteus minimus/medius tendinopathy with meta-analyses reporting sensitivity ranges of 33-100% and specificity ranges of 92-100% for detecting gluteus minimus/medius tendon tears 1
• Ultrasound has shown lower sensitivity (79%) for detecting gluteus minimus/medius tendon tears in patients with chronic greater trochanteric pain syndrome 1
• When directly comparing imaging modalities for proximal hamstring avulsion injuries (which shares similar soft tissue characteristics), MRI detected 100% of injuries while ultrasound detected only 58.3% 1
• In surgical correlation studies, ultrasound correctly identified 17 out of 19 pathological gluteus medius tendons but incorrectly classified 5 out of 6 normal tendons as pathological, demonstrating poor specificity 2

Advantages of MRI

• MRI provides comprehensive assessment of all peritrochanteric structures including the gluteus minimus and medius muscles, abductor tendons, and the trochanteric bursa 3, 4
• MRI can better classify the location, extent, degree (partial versus complete), and chronicity of tendon injuries 1
• MRI is particularly valuable for evaluating associated conditions like iliofemoral ligament and ligamentum teres injuries that may contribute to hip pain 1
• The American College of Radiology explicitly states that MRI without contrast is "usually appropriate when evaluating for clinically suspected tendon, muscle, or ligament injury as the source of hip pain" 4

Limitations of Ultrasound

• There is insufficient evidence to support ultrasound as the next imaging study for suspected tendon, muscle, or ligament injury according to the American College of Radiology 1
• Ultrasound has limited use in return-to-play decisions for athletes with hip injuries 1
• Both imaging modalities have shown limitations in differentiating between tendinosis and partial-thickness tears 2
• Ultrasound findings in greater trochanteric pain syndrome lack standardized definitions, leading to heterogeneous prevalence reports (7-93% for tendon pathology and 10-75% for bursitis) 5

Clinical Implications

• Initial radiographs should be obtained first to rule out other causes of hip pain before proceeding to advanced imaging 3, 4
• While ultrasound can detect trochanteric bursitis and some tendon pathology, it is difficult to distinguish between gluteus medius tendinosis and bursitis on ultrasound 3, 4
• Differentiation between trochanteric bursitis and gluteus medius/minimus tendinosis is clinically important but challenging, as these conditions frequently coexist 3, 4
• 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 3

Practical Approach to Imaging

• Begin with standard hip radiographs to rule out obvious bony abnormalities 6
• Proceed with non-contrast MRI of the hip as the definitive imaging study for suspected gluteus medius tendon pathology 1, 6
• Consider ultrasound primarily for guided interventions (e.g., corticosteroid injections) rather than as a primary diagnostic tool 3
• When surgical intervention is being considered, MRI provides more comprehensive information for surgical planning 7