From the Guidelines
Subacromial impingement syndrome should be diagnosed through a combination of clinical evaluation and imaging studies, prioritizing a stepwise conservative treatment approach to minimize morbidity, mortality, and improve quality of life. Diagnosis begins with a thorough history and physical examination, looking for pain with overhead activities and positive impingement signs such as the Neer and Hawkins tests 1. Imaging typically starts with plain radiographs to assess for bony abnormalities, followed by ultrasound or MRI if needed to evaluate soft tissue structures like the rotator cuff.
Treatment follows a conservative approach initially, starting with:
- Activity modification to avoid painful overhead movements
- First-line medications including NSAIDs such as ibuprofen (400-800mg three times daily) or naproxen (500mg twice daily) for 1-2 weeks to reduce inflammation
- Physical therapy focusing on posterior capsule stretching and rotator cuff and scapular strengthening exercises performed 3-4 times weekly for 6-12 weeks Corticosteroid injections (40mg methylprednisolone or equivalent with lidocaine) into the subacromial space may be considered for persistent pain, though typically limited to 2-3 injections per year, as evidence for their effectiveness is conflicting 1.
Given the lack of clinically important improvement in pain, function, or quality of life with arthroscopic subacromial decompression compared to other treatments, as reported in a recent umbrella review of level 1 evidence 1, surgical options should only be considered if conservative measures fail after 3-6 months. This approach prioritizes minimizing unnecessary invasive procedures and their associated risks, while addressing the underlying pathophysiology of impingement and promoting optimal patient outcomes.
From the Research
Diagnostic Steps for Subacromial Impingement Syndrome
- The diagnosis of subacromial impingement syndrome (SAIS) can be challenging due to the low specificity of various shoulder tests, with an average specificity of about 50% 2.
- Several clinical tests can be used to diagnose SAIS, including the Neer test, Hawkins test, and palpation tests for supraspinatus and biceps tendons 3, 4, 5.
- A modified Neer test (MNT) has been shown to have a high diagnostic accuracy rate of 90.59% and specificity of 95.56% in identifying SAIS 3.
- Palpation tests for supraspinatus and biceps tendons have been found to have a slightly higher accuracy than impingement tests in diagnosing Neer stage I and II SAIS 4.
- A combination of tests, including the painful arc, empty can, and external rotation resistance tests, can help confirm the diagnosis of SAIS, while a combination of the painful arc and external rotation resistance tests can help rule out the diagnosis 5.
- A systematic review found that the supraspinatus palpation test had a sensitivity of 92%, while the modified Neer test had a specificity of 95.56% in diagnosing SAIS 6.
Treatment Steps for Subacromial Impingement Syndrome
- Physiotherapy alone can provide good outcomes in treating SAIS, comparable to those achieved with surgery, without the costs and complications associated with surgery 2.
- Several randomized controlled trials have shown that the outcome of treatment of SAIS by surgery is no better than conservative treatment 2.
- There is a call by some practitioners to abandon the term impingement syndrome and rename it as anterolateral shoulder pain syndrome, as the impingement theory has become antiquated and surgical treatment may have no role in the treatment of SAIS 2.
- The use of palpation tests in a routine physical examination for tendinopathy can help rule out supraspinatus tendinopathy if tenderness does not exist 4.
- A combination of clinical tests and physical examination can help diagnose and treat SAIS effectively, reducing the need for surgical intervention 3, 4, 5, 6.