What diagnostic tests are done to diagnose Greater Trochanteric Pain Syndrome (GTPS)?

Diagnostic Tests for Greater Trochanteric Pain Syndrome (GTPS)

The diagnosis of Greater Trochanteric Pain Syndrome (GTPS) requires a combination of clinical examination, imaging studies, and diagnostic injections, with MRI being the preferred imaging modality when radiographs are negative or nondiagnostic.

Clinical Examination Tests

• The 30-second single-leg stance test has excellent sensitivity (100%) and specificity (97.3%) for diagnosing gluteal tendinopathy in patients with GTPS 1
• The resisted external derotation test in supine position (hip flexed 90 degrees) demonstrates 88% sensitivity and 97.3% specificity for identifying tendinous lesions and bursitis in GTPS 1
• Trendelenburg's sign is the most accurate physical examination finding for predicting gluteus medius tears, with a sensitivity of 72.7% and specificity of 76.9% 2
• Palpation over the greater trochanter to elicit pain is a key clinical examination technique for diagnosing GTPS 3

Imaging Studies

Initial Imaging

• Plain radiographs should be obtained first to rule out other causes of hip pain, though they have limited sensitivity for soft tissue pathology 4, 5
• Radiographs help exclude hip joint arthropathy and other bony abnormalities that may mimic GTPS 5

Advanced Imaging

• MRI is the preferred imaging modality for evaluating soft tissue abnormalities around the hip when radiographs are negative or nondiagnostic 4
• MRI can comprehensively assess peritrochanteric structures including:
  • Gluteus minimus and medius muscles
  • Abductor tendons
  • Trochanteric bursa 4, 5
• Ultrasound is effective for detecting:
  • Trochanteric bursitis
  • Gluteal tendinopathy
  • Calcium deposits (present in 97.7% of GTPS patients) 4, 6
• Ultrasound can identify specific pathological features including:
  • Tendon matrix changes
  • Calcifications (most commonly in gluteus medius)
  • Tendon thickness
  • Hypoechogenicity
  • Partial tears 6

Diagnostic Injections

• Diagnostic injection with local anesthetic (lidocaine) into the trochanteric bursa provides both diagnostic confirmation and potential therapeutic benefit 4, 5
• A positive response to injection (pain relief) confirms GTPS as the source of pain 4
• Ultrasound guidance improves the accuracy of diagnostic injections 5

Diagnostic Challenges

• Differentiation between trochanteric bursitis and gluteus medius/minimus tendinosis can be challenging on imaging, and these conditions frequently coexist 4, 5
• In patients with hip prostheses, extracapsular disease associated with adverse reactions to metal debris could be misinterpreted as trochanteric bursitis 5
• MRI studies show that GTPS often involves gluteus medius tendinopathy (97.7% of cases) and gluteus minimus tendinopathy (61.4% of cases) rather than isolated trochanteric bursitis 6, 2
• Trochanteric bursal distension is uncommon (found in only 40.9% of patients) and rarely occurs in the absence of gluteal tendon pathology 6, 2

Diagnostic Algorithm

1. Perform clinical examination including:

   • 30-second single-leg stance test
   • Resisted external derotation test
   • Assessment for Trendelenburg's sign
   • Palpation of greater trochanter 1, 2

2. Obtain plain radiographs to exclude hip joint pathology and other bony abnormalities 4, 5

3. If radiographs are negative or nondiagnostic, proceed with:

   • MRI to assess peritrochanteric soft tissue structures (preferred) 4
   • OR ultrasound to evaluate for bursitis and tendinopathy 4, 6

4. Consider diagnostic injection with local anesthetic for confirmation when clinical and imaging findings are equivocal 4, 5