- Also known as
- Subacromial pain syndrome
- Most common in
- Adults 35–60
- overhead workers
- First-line
- Physiotherapy + image-guided injection
- Surgery
- Selective only
- never for non-specific pain
- Imaging
- Plain X-ray + targeted ultrasound
What shoulder impingement is.
"Impingement" describes a clinical pattern, not a single diagnosis. It refers to pain produced when the structures beneath the acromion (most often the supraspinatus tendon and the subacromial bursa) are compressed or irritated during overhead movement. The mechanism is partly mechanical (the acromion, the bursa, the cuff insertion sharing a small space) and partly biological (tendon disease, bursal inflammation).
In modern terminology, many shoulders previously labelled "impingement" are now called subacromial pain syndrome or rotator cuff related shoulder pain. The shift in language reflects a shift in thinking: the pain is real, but the role of the bony acromion in causing it is much smaller than once believed.
Symptoms.
- A characteristic painful arc on lifting the arm out to the side, typically between 60° and 120°.
- Pain on overhead reach — hanging washing, reaching into a cupboard, putting on a seatbelt.
- Night pain, often when rolling onto the affected side.
- Weakness only because movement is painful (true strength is preserved when pain is blocked).
How Dr Coory diagnoses it.
The diagnosis is clinical. Examination identifies a painful arc, positive Neer and Hawkins-Kennedy signs, and tenderness over the greater tuberosity. The most useful single test in clinic is the injection test: an image-guided subacromial local anaesthetic injection that abolishes the pain confirms the symptom source.
Plain radiographs are taken to look for the acromial morphology, calcific deposits, AC joint arthritis and any glenohumeral pathology. Shoulder ultrasound (in trained hands) is the first-line imaging for the rotator cuff and bursa. MRI is reserved for atypical cases or pre-operative planning.
Non-operative treatment.
The mainstays of treatment are physiotherapy and, where appropriate, injection:
- Activity modification — temporarily reducing the provoking overhead activity.
- Targeted physiotherapy — emphasising scapular control and posterior cuff strengthening. A 6–12 week programme is reasonable.
- Image-guided subacromial corticosteroid injection — useful diagnostically (does the pain disappear when the bursa is anaesthetised?) and therapeutically (the steroid component reduces bursal inflammation for several months). Repeated injections are best limited to two.
- Analgesia and anti-inflammatories — short-course only.
When surgery is considered.
The published evidence on isolated subacromial decompression has moved considerably over the past decade. The 2018 CSAW trial and others showed that decompression in patients with non-specific subacromial pain — without a specific underlying lesion — produces results no better than diagnostic arthroscopy alone.1 As a result, isolated arthroscopic subacromial decompression is now performed selectively. The procedure remains appropriate in patients with a clearly demonstrable cause (e.g. a hooked acromion impinging directly on the cuff, calcific tendinitis being excised, or as an adjunct to rotator cuff repair).
It is not a first-line treatment, and not a treatment for non-specific shoulder pain. Dr Coory will explain whether your case fits the selective indication.
Frequently asked questions.
Do I need surgery for shoulder impingement?
Almost never as a first step. Most cases respond to a course of structured physiotherapy and, where appropriate, an image-guided subacromial injection. Surgery is reserved for the minority with a clearly demonstrable mechanical cause.
Will a cortisone injection cure my impingement?
Cortisone injection provides reliable short-to-medium term symptom relief in many patients with subacromial bursitis. It does not change the underlying tendon biology. Combined with a structured physiotherapy programme, it is the highest-yield non-operative treatment.
What is the difference between impingement and a rotator cuff tear?
Impingement is a pain pattern; rotator cuff tear is a structural diagnosis. They overlap — many people with impingement-pattern symptoms also have a partial or full-thickness cuff tear on imaging, particularly older patients. Diagnosis combines history, examination and imaging.
Is subacromial decompression still done?
Yes, selectively. The published evidence has moved against routine decompression for non-specific pain, but the procedure remains appropriate when a specific cause is present — a hooked acromion compressing the cuff, calcific tendinitis being addressed, or as an adjunct to cuff repair.
How long does physiotherapy take to work?
Most patients notice meaningful improvement within 6–8 weeks of a structured programme. A full course is generally 12 weeks before reassessing.
References.
- Beard DJ, et al. Arthroscopic subacromial decompression for subacromial shoulder pain (CSAW): a multicentre, pragmatic, parallel group, placebo-controlled, three-group, randomised surgical trial. Lancet. 2018;391(10118):329–338.
- Lewis J. Rotator cuff related shoulder pain: assessment, management and uncertainties. Man Ther. 2016;23:57–68.
- Diercks R, et al. Guideline for diagnosis and treatment of subacromial pain syndrome. Acta Orthop. 2014;85(3):314–322.