Adhesive capsulitis (Frozen shoulder)

Adhesive capsulitis, or frozen shoulder, is a painful shoulder condition characterised by progressive restriction of both active and passive glenohumeral range of motion, especially external rotation, with relatively unremarkable glenohumeral radiographs. X-ray may show no abnormality or non-specific findings such as disuse osteopenia or calcific tendinopathy.

The condition is due to inflammation, fibrosis and contracture of the glenohumeral joint capsule, causing mechanical restriction of movement. The aetiology is often unclear, especially in idiopathic or primary frozen shoulder.

Epidemiology

• Incidence/prevalence in the general population: approximately 2–5% / 3–5%
• More common in people aged 40–70 years
• Peak age often quoted around 56 years
• Slightly more common in women
• Uncommon before age 35 and unusual after 70
• More common in people with diabetes, with rates reported up to approximately 20% in some studies

Risk factors

Important risk factors include:

Risk factor	Notes
Diabetes mellitus	Strongest common association; can be bilateral or more resistant to treatment
Thyroid disease	Hypothyroidism and hyperthyroidism both associated
Hypercholesterolaemia	Recognised association
Hypertension	Recognised association
Female sex	Slightly higher risk
Age >40 years	Typical age group 40–70
Previous frozen shoulder	Risk of contralateral disease
Shoulder trauma or surgery	Secondary adhesive capsulitis
Prolonged immobilisation	After fracture, surgery, stroke, injury or pain-related guarding
Neurological disease / stroke	Can contribute through immobility and altered shoulder mechanics

BMJ Best Practice lists diabetes, thyroid disease, prior shoulder injury or surgery, and previous adhesive capsulitis as risk factors. RACGP/AJGP also lists diabetes, thyroid dysfunction, hypercholesterolaemia and hypertension as recognised associations.

Classification

Type	Meaning
Primary / idiopathic frozen shoulder	Spontaneous onset, no clear trigger
Secondary frozen shoulder	Occurs after trauma, surgery, fracture, rotator cuff pathology, prolonged immobilisation, stroke or other systemic disease

Clinical features

Typical symptoms:

• Gradual onset shoulder pain and stiffness
• Poorly localised, deep aching pain
• Pain often worse at night, especially in early phase
• Progressive loss of shoulder movement
• Difficulty with dressing, reaching overhead, grooming, bra fastening, reaching back pocket
• Usually no clear traumatic trigger in idiopathic cases
• No neurological symptoms unless another diagnosis coexists
• No systemic red flags such as fever, weight loss, night sweats or cancer symptoms

Key examination findings

The key examination finding is global restriction of passive glenohumeral movement, especially external rotation.

Findings:

• Reduced active and passive ROM
• External rotation most affected and often nearly absent
• Reduced abduction, forward flexion and internal rotation
• Capsular end-feel on passive movement
• Diffuse shoulder tenderness may be present
• Focal tenderness suggests another or additional diagnosis, such as AC joint pathology, biceps tendinopathy or rotator cuff disease
• Shoulder girdle wasting may occur due to disuse
• Reduced arm swing may be seen
• Neurovascular examination should be normal
• Cervical spine examination should be performed to exclude cervical radiculopathy

RACGP emphasises that confirming loss of both active and passive external rotation is important for diagnosis and that clinicians should distinguish true capsular restriction from pain-limited movement.

Red flags / alternative diagnoses to consider

Consider other diagnoses if there is:

• Trauma, deformity or suspected fracture
• History of cancer, unexplained weight loss or night sweats
• Fever, systemic illness or suspected septic arthritis
• Severe unremitting night pain
• Neurological deficit, radicular pain or pain below the elbow
• Marked weakness suggesting rotator cuff tear
• Localised AC joint tenderness
• Painful arc rather than global passive restriction
• Chest symptoms, smoking history or apical lung lesion concern, e.g. Pancoast tumour

Clinical phases

The phases overlap and are not always clinically distinct.

Phase	Duration	Clinical pattern
Painful / freezing phase	2–9 months	Increasing pain, night pain, pain at end range, progressive stiffness
Frozen / stiffness-predominant phase	4–12 months	Pain gradually improves, stiffness dominates, significant loss of ROM, especially external rotation
Thawing / resolution phase	12–42 months	Gradual improvement in ROM and function, variable residual stiffness

RACGP notes frozen shoulder has overlapping phases, with pain, stiffness and limited ROM varying across phases.

Differential diagnoses

Diagnosis	Differentiating features
Rotator cuff tendinopathy / tear	Painful arc, weakness, active ROM more limited than passive ROM
Calcific tendinopathy	Acute severe pain possible; calcification on X-ray/US
Subacromial bursitis	Painful arc, impingement signs, passive ROM relatively preserved
Glenohumeral osteoarthritis	X-ray changes; crepitus; older age
AC joint osteoarthritis	Localised ACJ tenderness, pain with cross-body adduction
Biceps tendinopathy	Anterior shoulder pain, Speed’s/Yergason’s positive
Cervical radiculopathy	Neck pain, pain below elbow, neurological symptoms, altered reflexes/sensation
Polymyalgia rheumatica	Bilateral shoulder/hip girdle pain, morning stiffness, raised inflammatory markers
Septic arthritis	Fever, severe pain, systemic illness, urgent
Malignancy / Pancoast tumour	Systemic symptoms, persistent severe pain, respiratory or neurological features

Investigations

X-ray

Frozen shoulder is mainly a clinical diagnosis, but X-ray is useful when the diagnosis is uncertain or to exclude other pathology.

X-ray may help assess for:

• Glenohumeral osteoarthritis
• Fracture or pathological fracture
• Avascular necrosis
• Calcific tendinopathy
• Tumour or other bony lesion
• Disuse osteopenia

Ultrasound

Ultrasound is not required to diagnose frozen shoulder, but may help assess coexisting pathology such as rotator cuff tear, bursitis or calcific tendinopathy.

Possible supportive ultrasound findings include:

• Reduced dynamic movement
• Difficulty positioning due to limited external rotation
• Thickened coracohumeral ligament
• Thickened inferior glenohumeral capsule
• Rotator interval changes

MRI / MR arthrogram

Usually not required in typical cases. May be useful if the diagnosis is unclear or if there are red flags or suspected alternative pathology.

Possible findings:

• Capsular thickening
• Rotator interval soft tissue thickening
• Pericapsular oedema/scarring
• Reduced axillary recess volume

Blood tests

Not routinely required for frozen shoulder itself, but consider screening for associated or alternative conditions when clinically indicated:

• HbA1c / fasting glucose for diabetes
• TSH for thyroid disease
• Lipids and BP assessment for cardiometabolic risk
• ESR/CRP if PMR, infection or malignancy is suspected

Management

1. Education and reassurance

Explain:

• It is a painful stiffening of the shoulder capsule.
• It is not usually dangerous, but can be very disabling.
• Recovery is usually gradual over months to years.
• Some patients have persistent symptoms.
• Treatment aims to reduce pain, preserve function and speed recovery.
• Avoid complete immobilisation, but do not force painful stretching during the painful phase.

2. Baseline function and monitoring

Use:

• Pain score
• ROM documentation, especially external rotation
• Functional impact: work, sleep, dressing, driving
• Shoulder Pain and Disability Index — SPADI

RACGP recommends SPADI as a useful baseline and serial measure of pain, disability, quality of life and work/function impact.

3. Analgesia

Options:

• Paracetamol if appropriate
• Short course NSAID if no contraindications
• Avoid prolonged NSAID use, especially in CKD, older age, hypertension, anticoagulation, peptic ulcer disease or cardiovascular risk
• Consider short-term stronger analgesia only if severe pain and function/sleep markedly affected

Topical agents are unlikely to alter the disease course; they may be used only if low risk and subjectively helpful.

4. Physiotherapy

Early physiotherapy is appropriate, but should match the phase:

Phase	Physiotherapy approach
Painful/freezing	Gentle ROM, pain control, avoid aggressive stretching
Frozen/stiffness phase	Progressive stretching, capsular mobilisation, home exercise
Thawing phase	Strengthening, function restoration, return to activity

RACGP states that involving a physiotherapist experienced in frozen shoulder is best practice and that conservative management is the mainstay for most patients.

5. Corticosteroid injection

Glenohumeral intra-articular corticosteroid injection can be considered, especially in the early painful phase, when pain limits sleep, function or physiotherapy.

Key points:

• More useful earlier in the condition
• Can improve pain and passive ROM
• Can be landmark-guided if skilled, or image-guided
• Use aseptic technique
• Check contraindications: infection, allergy, anticoagulation/bleeding risk, uncontrolled diabetes, recent surgery, prosthetic joint considerations
• Warn diabetic patients about transient hyperglycaemia

RACGP notes that glenohumeral injection in early stages can provide significant improvement and should be considered when analgesia and physiotherapy provide little or no benefit.

6. Hydrodilatation

Hydrodilatation involves distending the glenohumeral capsule with saline, usually combined with corticosteroid and sometimes local anaesthetic.

It may be considered when:

• Significant stiffness persists
• Early conservative measures are insufficient
• Injection plus physiotherapy is desired

RACGP describes hydrodilatation as injection of saline plus corticosteroid into the glenohumeral capsule to stretch the capsule and provide steroid benefit; it has evidence of effectiveness alone or with physiotherapy.

7. Referral / surgical options

Refer to sports physician, MSK physician or orthopaedic surgeon if:

• Diagnosis uncertain
• Red flags
• Severe functional impairment
• Failure of adequate conservative management
• Persistent disabling stiffness despite injection/hydrodilatation/physio

Specialist options include:

• Manipulation under anaesthesia
• Arthroscopic capsular release

surgery is generally reserved for refractory case