Shoulder Impingement Syndrome
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Direct answer
Shoulder impingement syndrome is pain produced when the rotator cuff and subacromial bursa are compressed beneath the coracoacromial arch during elevation. It causes a painful arc between roughly 60 and 120 degrees of abduction, and the Neer and Hawkins-Kennedy tests reproduce the pain. Initial care is conservative, with physiotherapy and an injection, and subacromial decompression is reserved for symptoms that persist after several months of rehabilitation.
What you must remember
- Neer sign: forced passive forward flexion with the arm internally rotated reproduces pain as the greater tuberosity meets the anterior acromion.
- Hawkins-Kennedy test: the arm is flexed to 90 degrees and forcibly internally rotated; pain confirms compression of the cuff under the coracoacromial ligament.
- Painful arc: pain between about 60 and 120 degrees of abduction, the range in which the cuff passes beneath the acromion.
- Neer stages: stage I is oedema and haemorrhage in patients under 25, stage II is fibrosis and tendinitis between 25 and 40, and stage III is bone spur and tear in patients over 40.
- Bigliani types: a flat type I, curved type II and hooked type III acromion; the hooked form is linked to rotator cuff tears.
- Conservative first: activity modification, scapular and cuff strengthening, and a subacromial corticosteroid injection for pain that is not settling.
- Surgery: arthroscopic subacromial decompression with acromioplasty and coracoacromial ligament release, for persistent symptoms after adequate rehabilitation.
Matching the Neer stage to the patient
Neer's staging ties the pathology to the patient's age, which in turn predicts the likely course. The same painful arc can therefore mean different things in a 22-year-old and a 55-year-old.
| Stage | Typical age | Pathology | Usual approach |
|---|---|---|---|
| I | Under 25 | Oedema and haemorrhage | Rest and physiotherapy |
| II | 25 to 40 | Fibrosis and tendinitis | Rehabilitation and injection |
| III | Over 40 | Bone spur and cuff tear | Decompression, repair if torn |
Early stages usually resolve with rehabilitation, whereas stage III often carries a genuine cuff tear that changes the plan. Examiners often ask which stage the patient's age and tear status place them in.
The Neer and Hawkins tests are best used together, since neither is specific on its own. A positive result alongside a painful arc and weakness on resisted abduction points more firmly toward a cuff problem.
Where the exam tries to catch you
Impingement is a diagnosis of exclusion as often as of confirmation.
- Trap: labelling every painful elevation as impingement Correct: exclude cervical radiculopathy, acromioclavicular pain, biceps disease and cuff tear with examination and imaging.
- Trap: operating for impingement without a trial of rehabilitation Correct: decompression is reserved for symptoms that persist after several months of structured physiotherapy.
- Trap: deciding that a hooked acromion always needs decompression Correct: the type III acromion is linked to cuff tears, but treatment follows symptoms and tear status.
Frequently asked questions
What is the Neer sign?
The Neer sign is pain on forced passive forward flexion with the arm internally rotated, which pushes the greater tuberosity against the anterior acromion. A positive Neer sign supports subacromial impingement as the cause of the pain.
What does a painful arc between 60 and 120 degrees indicate?
That range suggests subacromial impingement, because the cuff tendons are compressed beneath the coracoacromial arch during mid-range elevation. Pain confined to the end of elevation raises the possibility of acromioclavicular joint disease instead.
Which acromion type is linked with rotator cuff tears?
The hooked type III acromion in Bigliani's classification is associated with rotator cuff tears. Its shape can be assessed on a supraspinatus outlet radiograph, which shows the anterior acromial profile.
When is subacromial decompression indicated?
Subacromial decompression is indicated when symptoms persist after several months of structured physiotherapy and injection. The arthroscopic procedure removes the anterior acromion and releases the coracoacromial ligament.