What is the etiology and management of shoulder impingement?

From the Guidelines

Shoulder impingement syndrome should be managed conservatively with rest, activity modification, NSAIDs, and physical therapy as the first line of treatment, reserving surgery for patients who fail conservative management after 6 months or have significant structural abnormalities. This approach is supported by the most recent and highest quality study, which emphasizes the importance of non-operative care and highlights the limitations and potential risks of surgical interventions 1. The study suggests that surgery should be considered as a second-line treatment when non-surgical measures have failed, and that high-level evidence is needed to support the use of surgery.

Conservative Management

Conservative management of shoulder impingement syndrome includes:

• Rest and activity modification to reduce inflammation and avoid exacerbating the condition
• 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 rotator cuff strengthening exercises, scapular stabilization, and proper movement patterns to restore normal shoulder biomechanics
• Patients should perform these exercises 3-4 times weekly for at least 6-8 weeks

Role of Corticosteroid Injections

For persistent pain, corticosteroid injections (such as methylprednisolone 40mg with lidocaine) into the subacromial space can provide temporary relief, though typically limited to 2-3 injections per year 1. However, the evidence for the effectiveness of corticosteroid injections is conflicting, and their use should be carefully considered.

Surgery

Surgery (subacromial decompression) is reserved for patients who fail conservative management after 6 months or have significant structural abnormalities. The study highlights the importance of prioritizing research to determine the effectiveness of surgical interventions and to identify the optimal timing for surgery 1.

Prevention Strategies

Prevention strategies include:

• Proper warm-up before overhead activities
• Maintaining good posture
• Avoiding repetitive overhead movements when possible Early intervention is key to preventing chronic shoulder dysfunction and rotator cuff damage.

From the Research

Etiology of Shoulder Impingement

• Shoulder impingement syndrome is often associated with subacromial impingement syndrome, which can be caused by various factors such as acromioclavicular joint arthritis, calcified coracoacromial ligament, structural abnormalities of the acromion, and weakness of the rotator cuff muscles 2
• Altered biomechanics and/or structural abnormalities can also contribute to the development of shoulder impingement syndrome 3

Management of Shoulder Impingement

• Conservative treatment options include rest, ice packs, nonsteroidal anti-inflammatory drugs, and physical therapy, which are usually sufficient for managing shoulder impingement syndrome 2
• Corticosteroid injections (CSIs) are a recommended and often-used first-line intervention for shoulder impingement syndrome, but their long-term efficacy is questionable 4
• Manual physical therapy (MPT) offers a non-invasive approach with negligible risk for managing shoulder impingement syndrome, and its effectiveness has been compared to CSIs in several studies 5, 6, 4
• A study found that both CSIs and MPT demonstrated approximately 50% improvement in Shoulder Pain and Disability Index scores at 1 year, but the mean difference between groups was not significant 5
• Another study found that CSIs showed an improvement in shoulder function at 6-7 weeks, but no evidence was found for the superiority of CSIs compared to physiotherapy for pain and range of motion over 4-12 weeks 6

Treatment Outcomes

• Patients receiving CSIs had more shoulder impingement syndrome-related visits to their primary care provider and required additional steroid injections, and some needed physical therapy 5
• MPT was found to use less 1-year shoulder impingement syndrome-related health care resources than CSIs 5
• A study recommended a weak recommendation with moderate quality of evidence based on three randomized controlled trials for the use of CSIs or physiotherapy for managing shoulder impingement syndrome 6