What is subacromial bursitis?

Subacromial Bursitis: Diagnosis and Management

Subacromial bursitis is an inflammatory condition of the bursa located between the acromion process and the rotator cuff tendons, most commonly treated with a combination of exercise therapy and NSAIDs as first-line management, with corticosteroid injections reserved for cases that don't respond to initial treatment. 1

Clinical Presentation and Diagnosis

Subacromial bursitis presents with:

• Pain in the lateral shoulder area, often aggravated by overhead activities
• Pain with specific arm movements, particularly abduction
• Tenderness over the lateral/anterior acromion
• Positive special tests:
  • Hawkins test (92% sensitivity, 25% specificity)
  • Neer test (88% sensitivity, 33% specificity) 1

Diagnostic approach:

1. Clinical examination with special tests
2. Ultrasound as first imaging choice to exclude rotator cuff tears
3. Standard radiographs to evaluate for anatomical abnormalities (e.g., acromial morphology)
4. MRI for more detailed evaluation if needed 1

Treatment Algorithm

First-Line Treatment (0-6 weeks)

• Exercise therapy focusing on gentle, progressive stretching and range of motion exercises
• NSAIDs (oral or topical) for pain and inflammation
• Activity modification to reduce movements that exacerbate pain 1

Second-Line Treatment (if inadequate response after 4-6 weeks)

• Subacromial corticosteroid injection with lidocaine
  • Can decrease pain by approximately 38% within 24 hours
  • Provides significant pain relief for up to 12 weeks
  • Higher doses of triamcinolone (20mg vs 10mg) may offer more substantial and sustained improvement in pain relief 1, 2
• Continue exercise program alongside injection therapy 1

Third-Line Treatment (if minimal improvement after 3-6 months)

• Consider surgical consultation
• Extracorporeal shock wave therapy (ESWT) may be considered, particularly for calcific tendinitis 1

Evidence-Based Insights

The American Academy of Orthopaedic Surgeons notes that there is no convincing evidence that surgical treatment for subacromial impingement syndrome is more effective than conservative management. The primary indication for rotator cuff repair is significant pain, not just the presence of a tear 1.

Most cases (>90%) of subacromial bursitis have a good prognosis with appropriate conservative management, making non-operative approaches the clear first choice for initial management 1.

Special Considerations and Cautions

• Ultrasound-guided injections improve precision and minimize risk compared to blind injections 2
• Diabetic patients may respond less favorably to conservative measures and may require modified approaches 1
• Patients with more severe disease, longer symptom duration, and type II or III acromion morphology may respond less favorably to conservative treatments 1
• Repeated corticosteroid injections without concurrent exercise therapy may lead to poorer long-term outcomes 1
• Rare but serious complications include infection, including methicillin-resistant Staphylococcus aureus (MRSA) infection of the subacromial bursa 3
• Alternative injection therapies such as botulinum toxin type B have shown promising results for longer-term pain relief compared to corticosteroids 4
• In rare cases, massive subacromial bursitis can mimic neoplastic lesions, particularly in patients with rheumatoid arthritis 5

Emerging Research

Recent research has highlighted the regenerative potential of the subacromial bursa, with bursa-derived cells showing stem cell potential that may augment healing of adjacent tissues such as rotator cuff tendons 6. This suggests that complete removal of the bursa during surgery may not always be beneficial, and preservation of this tissue might support healing in some cases.