Shoulder Pain
Shoulder pain is the third most common musculoskeletal complaint in primary care, most commonly caused by rotator cuff pathology, managed with physiotherapy-led exercise programmes as first-line treatment.
Key Facts
Shoulder pain affects 16-26% of adults at any time; third most common MSK complaint in primary care Rotator cuff tendinopathy/tear is the most common cause (70%); other causes include adhesive capsulitis, acromioclavicular joint pathology, and glenohumeral OA Adhesive capsulitis (frozen shoulder): global restriction of active and passive movement; affects 2-5%, more common in diabetics (10-20%) Supraspinatus is the most commonly affected rotator cuff tendon; painful arc between 60-120° abduction Physiotherapy and exercise are first-line treatment for most shoulder conditions (NICE CKS, BESS guidelines) Subacromial corticosteroid injection (40mg methylprednisolone + 1% lidocaine): short-term pain relief; maximum 3 injections per year Red flags: trauma with inability to move arm (fracture/dislocation), rapidly progressive weakness (acute rotator cuff tear), hot swollen joint (septic arthritis), constitutional symptoms + shoulder pain (malignancy) USS or MRI: for diagnostic uncertainty, suspected complete rotator cuff tear, or symptoms not improving after 6-8 weeks of physiotherapy
Overview
Key Facts
Shoulder pain is extremely common and a significant cause of functional limitation. Most cases are due to soft tissue pathology around the shoulder, particularly the rotator cuff. Management is predominantly conservative, with physiotherapy as the cornerstone.
Epidemiology
- Point prevalence: 16-26% of adults
- Annual incidence in primary care: 15 per 1,000 registrations
- Increases with age, peaking at 45-64 years
- Rotator cuff pathology accounts for 70% of shoulder pain
Aetiology
- Rotator cuff tendinopathy/tears: supraspinatus most common; degeneration, impingement, overuse
- Adhesive capsulitis (frozen shoulder): idiopathic, diabetes, thyroid disease, immobility
- Acromioclavicular joint: OA, osteolysis, injury
- Glenohumeral OA: less common than hip/knee OA
- Instability: anterior dislocation (young, traumatic), multidirectional (hypermobility)
- Referred pain: cervical spine, cardiac, diaphragmatic, apical lung tumour (Pancoast)
Pathophysiology
- Rotator cuff: four muscles (supraspinatus, infraspinatus, teres minor, subscapularis) stabilise the humeral head in the glenoid
- Tendinopathy: degenerative rather than inflammatory; failed healing response, collagen disorganisation
- Impingement: mechanical compression of rotator cuff between humeral head and acromion during overhead activities
- Adhesive capsulitis: fibrosis and contracture of glenohumeral joint capsule; three phases — freezing, frozen, thawing
- Calcific tendinopathy: calcium hydroxyapatite deposits within rotator cuff tendons, causing acute inflammatory pain
Clinical Presentation
Rotator Cuff Tendinopathy
- Lateral/anterolateral shoulder pain
- Painful arc (60-120° abduction)
- Worse with overhead activities
- Night pain (sleeping on affected side)
- Positive impingement tests (Neer, Hawkins-Kennedy)
Adhesive Capsulitis (Frozen Shoulder)
- Global restriction of both active AND passive movement
- Especially external rotation and abduction
- Three phases: freezing (painful, 2-9 months), frozen (stiff, 4-12 months), thawing (recovery, 5-24 months)
- Total duration: 12-30 months; may not fully resolve
Acute Rotator Cuff Tear
- Sudden weakness after trauma or fall
- Unable to initiate abduction (complete supraspinatus tear)
- Drop arm test positive
Red Flags
- Acute traumatic injury with deformity (fracture/dislocation)
- Hot, swollen joint with fever (septic arthritis)
- Progressive weakness (complete rotator cuff tear, neurological cause)
- Shoulder pain with weight loss/malaise (malignancy — Pancoast tumour)
- Shoulder pain radiating to arm with cervical signs (referred from C-spine)
Differential Diagnosis
| Diagnosis | Key Features | Investigation |
|---|---|---|
| Rotator cuff tendinopathy | Painful arc, impingement signs, preserved passive ROM | USS |
| Adhesive capsulitis | Global restriction active + passive ROM, diabetic | Clinical diagnosis |
| AC joint pathology | Pain on cross-body adduction, localised tenderness | X-ray AC joint |
| Glenohumeral OA | Crepitus, reduced ROM, age >60 | X-ray |
| Calcific tendinopathy | Acute severe pain, restriction, calcium on X-ray | X-ray, USS |
| Cervical radiculopathy | Dermatomal arm pain, neck involvement, Spurling positive | MRI C-spine |
| Pancoast tumour | Shoulder/arm pain, Horner syndrome, smoker | CXR, CT chest |
Diagnosis / Investigation
Bedside
- Full shoulder examination: inspection, palpation, range of motion (active and passive), strength, special tests
- Painful arc (60-120°): rotator cuff impingement
- Neer test, Hawkins-Kennedy: impingement
- Empty can test (Jobe): supraspinatus
- Drop arm test: complete rotator cuff tear
- External rotation lag sign: infraspinatus
- Belly press, lift-off: subscapularis
- Cross-body adduction: AC joint
Imaging
- X-ray: first-line if trauma, OA suspected, or persistent symptoms; assess acromion morphology, calcification, OA
- USS: excellent for rotator cuff assessment; operator-dependent; first-line soft tissue imaging
- MRI: gold standard for comprehensive assessment; rotator cuff tears, labral pathology, bone marrow
Bloods
- Not routinely required
- CRP, WCC: if septic arthritis suspected
- HbA1c: screen for diabetes in adhesive capsulitis
- TFTs: associated with adhesive capsulitis
Management
Non-pharmacological
- Physiotherapy and exercise: first-line for all shoulder conditions; supervised exercise programme for rotator cuff (progressive loading, strengthening, range of motion)
- Activity modification: avoid aggravating overhead activities temporarily
- Adhesive capsulitis: physiotherapy (gentle stretching, not aggressive mobilisation); may use hydrodilatation
Pharmacological
- NSAIDs: ibuprofen 400mg TDS or naproxen 250-500mg BD (short course for acute pain)
- Paracetamol: as adjunct
- Subacromial corticosteroid injection: methylprednisolone 40mg + 1% lidocaine; short-term benefit (4-6 weeks); maximum 3 injections/year
- Intra-articular injection: for adhesive capsulitis or glenohumeral OA
Surgical
- Arthroscopic subacromial decompression: controversial; CSAW trial showed no benefit over placebo (Lancet 2018)
- Rotator cuff repair: for complete tears in active patients, acute traumatic tears
- Manipulation under anaesthesia or arthroscopic capsular release: for refractory adhesive capsulitis
- Shoulder arthroplasty: for severe glenohumeral OA (total or reverse shoulder replacement)
Referral Criteria
- Urgent: suspected septic arthritis, acute traumatic complete rotator cuff tear (young/active)
- Routine orthopaedic: failed 3-6 months conservative management, significant rotator cuff tear, adhesive capsulitis >12 months, glenohumeral OA for arthroplasty consideration
- Physiotherapy: all shoulder pain for exercise programme
Prognosis
- Rotator cuff tendinopathy: >70% improve with physiotherapy at 6 months
- Adhesive capsulitis: natural history 12-30 months; most recover good function; 20-50% have persistent minor restriction
- Rotator cuff tear: small tears may be managed conservatively; large/complete tears in young active patients usually require surgery
- Subacromial decompression: CSAW trial (Lancet 2018) showed no significant benefit over placebo surgery
- Corticosteroid injections: effective short-term (4-6 weeks); no long-term benefit; may weaken tendons if repeated
- Psychosocial factors (fear-avoidance, kinesiophobia) influence outcomes significantly
Other Relevant Information
Rotator Cuff Muscles — SITS
| Muscle | Action | Test | Nerve |
|---|---|---|---|
| Supraspinatus | Initiation of abduction (0-15°) | Empty can (Jobe) | Suprascapular (C5,6) |
| Infraspinatus | External rotation | External rotation lag | Suprascapular (C5,6) |
| Teres minor | External rotation | Same as infraspinatus | Axillary (C5,6) |
| Subscapularis | Internal rotation | Belly press, lift-off | Subscapular (C5,6,7) |
Adhesive Capsulitis — Three Phases
| Phase | Duration | Features |
|---|---|---|
| Freezing (painful) | 2-9 months | Pain predominant, gradual loss of ROM |
| Frozen (stiff) | 4-12 months | Pain eases, stiffness maximal |
| Thawing (recovery) | 5-24 months | Gradual return of ROM |
CSAW Trial (Lancet 2018)
| Finding | Detail |
|---|---|
| Comparison | Arthroscopic subacromial decompression vs arthroscopy alone vs no treatment |
| Result | No significant difference in shoulder pain at 6 or 12 months |
| Conclusion | Subacromial decompression offers no benefit over placebo surgery |