What diagnostics are used for rotator tendinitis?

Diagnostic Approach to Rotator Tendinitis

For diagnosing rotator tendinitis, a structured clinical examination combined with appropriate imaging is essential, with MRI being the most accurate diagnostic tool (95% sensitivity and specificity) for detecting rotator cuff pathology. 1

Clinical Examination

History Taking

• Look for specific symptoms:
  • Insidious onset of load-related localized pain
  • Pain that increases with activity, especially overhead movements
  • Pain that may subside after a warm-up period initially
  • Pain described as "sharp" or "stabbing"
  • History of new activity or increased intensity of current activity
  • Pain that gradually increases in intensity and duration
  • Pain that may be present at rest in later stages 1

Physical Examination

1. Inspection:

   • Muscle atrophy (indicates chronicity)
   • Asymmetry between shoulders
   • Swelling and erythema
   • Joint effusions (uncommon in tendinopathy, suggests intra-articular pathology)

2. Range of Motion Testing:

   • Assess active and passive range of motion (often limited on affected side)
   • Document limitations using a goniometer for objective measurement

3. Palpation:

   • Localized tenderness that reproduces patient's pain
   • Note: Palpation may be limited with supraspinatus tendinopathy due to anatomic location 1

4. Special Tests:

   • Hawkins' Test: Pain with forcible internal rotation with arm passively flexed forward at 90° (92% sensitive but only 25% specific)
   • Neer's Test: Pain with full forward flexion between 70-120° (88% sensitive but only 33% specific)
   • Tests that simulate tendon loading and reproduce pain support diagnosis 1

Imaging Studies

Plain Radiography

• First-line imaging study
• Limited ability to show soft tissue changes of tendinopathy
• Can reveal:
  • Sclerosis or spur formation of acromion
  • Calcific tendinosis
  • Other bony pathology causing pain 1

Ultrasonography

• Excellent for detecting:
  • Moderate to full thickness tears
  • Tendon changes of chronic tendinopathy
  • Tendon thickening and heterogeneous echogenicity
  • Limited ability to detect small tears 1
• Advantages:
  • Non-invasive
  • Dynamic assessment possible
  • Can guide therapeutic injections
  • No radiation exposure
  • Cost-effective 1

MRI

• Gold standard for rotator cuff assessment
• Highly sensitive (95%) and specific (95%) for:
  • Cuff tears (partial and complete)
  • Degeneration
  • Chronic tendinopathy 1
• Can detect:
  • Tendinosis (enlarged tendon with heterogeneous signal pattern)
  • Partial-thickness tears (articular, bursal, or intrasubstance)
  • Full-thickness tears (increased signal intensity extending through tendon)
  • Muscle atrophy and fatty infiltration (important for surgical planning) 1

Advanced Imaging (for specific scenarios)

• MR Arthrography: For suspected labral pathology or partial articular-sided tears
• CT Arthrography: When MRI is contraindicated
• Nuclear Medicine Studies: For suspected infection or when other imaging is inconclusive 1

Diagnostic Algorithm

1. Initial Assessment: Clinical examination + plain radiographs
2. If diagnosis remains unclear or for treatment planning:
   • First choice: MRI without contrast (95% sensitivity/specificity) 1
   • Alternative: Ultrasound if MRI contraindicated or unavailable (especially if local expertise available) 1
3. For persistent symptoms despite treatment:
   • Consider MRI if not done previously
   • Consider MR arthrography for suspected labral involvement

Common Pitfalls and Caveats

1. Misdiagnosis: Many providers incorrectly label all rotator cuff pain as "tendinitis" when most cases are degenerative tendinopathy without significant inflammation 1

2. Inadequate Imaging: Plain radiographs alone are insufficient for definitive diagnosis of tendinopathy

3. Incidental Findings: Remember that 10% of rotator cuff tears are asymptomatic and may be incidental findings 1

4. Overlooking Associated Conditions: Assess for:

   • Subacromial impingement
   • Acromioclavicular joint pathology
   • Biceps tendon involvement
   • Multiple symptomatic tendons (may indicate rheumatic disease) 1

5. Delayed Diagnosis: Further imaging should not be delayed when symptoms persist despite adequate conservative management 1