Shoulder Impingement Syndrome
Pain from the subacromial space, where the cuff tendons and bursa lie beneath the acromion and coracoacromial arch. Modern term: <strong>subacromial pain syndrome (SAPS)</strong>.
A contested model
Neer (1972)
Problems with this model:
- Asymptomatic people often show “impingement” on imaging.
- Subacromial decompression is no better than placebo surgery.
- The acromion is probably not the main pain generator in most patients.
Impingement is better understood as a descriptive sign on the same continuum as rotator cuff tendinopathy, not a separate disease. Proposed mechanisms are extrinsic (narrowed space, scapular control) and intrinsic (tendon degeneration with secondary swelling), usually combined.
Risk factors
- Modifiable: repetitive overhead activity, cuff weakness, scapular dyskinesis, thoracic kyphosis and forward shoulder posture, load spikes
- Non-modifiable: age, hooked acromion (contested), AC joint arthrosis
- Metabolic: diabetes, metabolic syndrome
- Sports: swimming, throwing, tennis, volleyball, overhead pressing
Presentation
- Anterolateral shoulder pain, often referred to the deltoid
- Painful arc 60 to 120° abduction
- Night pain, especially lying on the affected side
- Provoked by overhead activity, reaching behind the back and lifting
Special tests: interpret with caution
| Test | Method |
|---|---|
| Neer | Passive forward flexion in internal rotation |
| Hawkins-Kennedy | Internal rotation at 90° flexion |
| Empty can (Jobe) | Resisted abduction in internal rotation |
Specificity is poor (about 50%). A positive test reproduces pain in a shoulder that is already painful. Diagnose clinically and combine with cuff strength testing.
Management
- Exercise therapy (cuff and scapular): first-line, equal to decompression surgery in randomised trials.
- Load management, posture and scapular retraining.
- Adjuncts: manual therapy, short-term NSAIDs. Shockwave and laser have weak or emerging evidence.
- Subacromial corticosteroid: short-term relief to enable rehab, not a long-term solution.
- Surgery: not recommended for non-traumatic subacromial pain. If considered, only after 6+ months of failed structured care, and its added benefit is questionable.
The updated multidisciplinary SAPS guideline recommends exercise first and cautions against surgery.
References
- Redefining anterior shoulder impingement, Int Orthop 2018, doi:10.1007/s00264-017-3515-1
- Update of guideline for subacromial pain syndrome, Acta Orthop 2026, doi:10.2340/17453674.2026.45410
Related
Medical disclaimer: this article is general information, not personal medical advice. Always consult a qualified doctor about your own situation.