Frozen shoulder is a painful and disabling shoulder condition characterised by a progressive loss of movement and function. It is also known as adhesive capsulitis, 50-year-old shoulder, and frozen shoulder contracture syndrome, with all of these terms referring to the same clinical presentation. The wide range of names highlights an important issue. There is still no single, universally accepted explanation for exactly what is happening inside the shoulder, or why the condition develops in the first place.
The term “frozen shoulder” suggests a freezing and thawing process, while adhesive capsulitis implies the formation of adhesions within the shoulder capsule. Other theories propose chronic inflammation, capsular thickening and shrinking, immune system involvement, altered nerve sensitivity, or trauma as contributing factors. The reality is likely multifactorial. Not only is there uncertainty around the underlying pathology, there is also limited clarity around why some people develop frozen shoulder while others do not. This uncertainty makes assessment and management challenging and highlights the importance of a tailored, physiotherapy-led approach.
Frozen shoulder most commonly affects people between 40 and 65 years of age and is more prevalent in individuals with metabolic or systemic conditions such as diabetes. Physiotherapy plays a central role in frozen shoulder management by guiding pain control, maintaining movement where possible, and progressively restoring shoulder mobility and function as the condition evolves.
Key Facts
- Symptoms may persist for 12 to 36 months.
- People with diabetes are up to five times more likely to develop frozen shoulder compared to the general population.
- External rotation is typically the most restricted movement in frozen shoulder.
Risk Factors
- Age between 40 and 65 years
- Diabetes (type 1 and type 2)
- Thyroid disorders
- Cardiovascular disease
- Prolonged shoulder immobilisation
- Previous shoulder injury or surgery
- Female sex
Symptoms
- Severe shoulder pain, often poorly localised
- Night pain that disrupts sleep
- Progressive shoulder stiffness
- Marked loss of active and passive shoulder movement
- Significant restriction in external rotation
- Difficulty reaching overhead
- Difficulty reaching behind the back
- Reduced ability to perform daily activities
Aggravating Factors
- Sleeping on the affected shoulder
- Reaching overhead or away from the body
- Putting the arm behind the back
- Sudden or forced shoulder movements
- Prolonged inactivity of the shoulder
Causes
The exact cause of frozen shoulder remains unclear. It is considered an idiopathic condition in many cases, meaning it develops without a clearly identifiable trigger. Several mechanisms have been proposed, including chronic inflammation of the joint capsule, capsular fibrosis and thickening, formation of adhesions, immune-mediated responses, and altered pain processing.
Histological studies have shown increased fibroblast activity and collagen deposition within the shoulder capsule, leading to capsular tightening and reduced joint volume. This capsular contracture restricts movement and contributes to pain, particularly at the end of range. In some individuals, frozen shoulder may follow trauma, surgery, or prolonged shoulder immobilisation, though many cases occur without any clear injury.
Physiotherapists consider frozen shoulder a whole-joint disorder rather than a muscle or tendon problem. Management therefore focuses on restoring shoulder joint mobility while respecting pain levels and the current stage of the condition.
How Is It Diagnosed?
Frozen shoulder is primarily a clinical diagnosis made by a physiotherapist or medical practitioner. Diagnosis is based on a combination of patient history and physical examination findings. The hallmark feature is a significant loss of both active and passive shoulder range of motion, particularly external rotation.
Physiotherapists assess pain behaviour, stiffness patterns, and functional limitations. Importantly, passive movement is restricted in frozen shoulder, which helps differentiate it from rotator cuff tears or bursitis where passive range is often preserved. Imaging is not diagnostic for frozen shoulder but is commonly used to exclude other causes of shoulder pain.
Investigations & Imaging
- X-ray
- Typically normal and used to rule out fracture, arthritis, avascular necrosis, dislocation, or tumour.
- Ultrasound
- May be used to assess the rotator cuff and exclude alternative pathology.
- MRI
- Occasionally shows capsular thickening but is mainly used to rule out other shoulder conditions.
Grading / Classification
- Freezing stage
- This is the early stage of frozen shoulder and is characterised by progressively worsening shoulder pain with a gradual loss of movement. Pain is often severe, poorly localised, and commonly worse at night, significantly affecting sleep. Both active and passive range of motion begin to reduce, with external rotation typically affected first. This stage commonly lasts 2 to 9 months, though the rate of progression varies between individuals.
- Frozen stage
- During the frozen stage, pain may begin to stabilise or slightly reduce, however shoulder stiffness becomes the dominant feature. There is marked restriction of both active and passive shoulder movement in all directions, leading to significant functional limitations with overhead tasks and reaching behind the back. Night pain may persist but is often less intense than in the freezing stage. This stage typically lasts 4 to 12 months.
- Thawing stage
- The thawing stage is characterised by a gradual improvement in shoulder mobility and function as capsular stiffness slowly resolves. Pain continues to settle and becomes less prominent, allowing greater tolerance to movement and activity. Improvements in range of motion can be slow but progressive. The thawing stage commonly lasts 6 to 24 months, with some individuals experiencing residual stiffness beyond this period.
Physiotherapy Management
While frozen shoulder is commonly described in stages, physiotherapy management is not determined by stage alone. Treatment is more effectively guided by whether pain or stiffness is the dominant limiting factor at a given point in time. These can fluctuate and do not always follow a predictable timeline.
Exercise
Exercise prescription in frozen shoulder is highly dependent on symptom presentation. When pain is greater than stiffness, exercises focus on gentle, pain-limited range of motion to maintain joint health without provoking flare-ups. As stiffness becomes the primary issue, physiotherapists progressively introduce more assertive stretching and mobility exercises aimed at improving capsular extensibility. Exercises are carefully dosed to avoid excessive post-exercise pain.
Activity Modification
Physiotherapists provide guidance on modifying daily activities to reduce pain while maintaining shoulder use. Complete rest is discouraged, as inactivity may worsen stiffness. Education around sleeping positions, dressing strategies, and work modifications is essential.
Manual Therapy
Manual therapy plays a greater role once stiffness exceeds pain. Shoulder joint mobilisation techniques are used to target capsular restriction, particularly into external rotation and elevation. Thoracic spine mobilisation is also commonly included to improve overall shoulder mechanics.
Postural Retraining
Postural adaptations often develop secondary to pain and stiffness. Physiotherapists address thoracic and scapular posture to optimise shoulder movement and reduce compensatory patterns.
Heat & Ice
Heat is commonly used to assist with pain relief and muscle relaxation, particularly prior to stretching exercises. Ice may be used for short-term pain relief during painful phases but is generally less effective once stiffness predominates.
Education
Education is a cornerstone of frozen shoulder physiotherapy. Understanding the condition, expected timelines, and the rationale for treatment reduces anxiety and improves adherence. Patients are reassured that frozen shoulder is a self-limiting condition, though recovery may be prolonged.
Other
Close communication with medical practitioners is important. Physiotherapists help guide timing and appropriateness of injections or procedures based on symptom behaviour.
Other Treatments
Corticosteroid injections can be beneficial when pain is the dominant symptom. Evidence suggests they may reduce pain and improve short-term function when combined with physiotherapy.
Hydrodilatation may be considered when stiffness is the primary limitation, as it aims to stretch the joint capsule and improve movement. Timing is critical, as performing hydrodilatation during a pain-dominant phase can significantly aggravate symptoms.
Surgery
Surgery is rarely required for frozen shoulder. Options such as manipulation under anaesthesia or arthroscopic capsular release are reserved for cases that do not improve with prolonged conservative management. Post-surgical physiotherapy is essential to maintain gains in range of motion and prevent recurrence.
Prognosis & Return to Activity
Frozen shoulder is generally a self-limiting condition, but recovery can take 12 to 36 months. With physiotherapy, many people experience improved pain control, faster functional recovery, and better long-term outcomes. Return to activity is gradual and guided by symptom response rather than rigid timelines.
Complications
- Prolonged pain and stiffness
- Long-term loss of shoulder range of motion
- Sleep disturbance
- Reduced work or sporting capacity
Preventing Recurrence
- Maintain shoulder movement following injury or surgery
- Avoid prolonged shoulder immobilisation
- Address shoulder pain early with physiotherapy
- Manage underlying conditions such as diabetes
- Maintain thoracic spine and shoulder mobility
When to See a Physio
- Persistent shoulder pain and stiffness
- Night pain affecting sleep
- Progressive loss of shoulder movement
- Difficulty with daily activities
- After shoulder injury or surgery with increasing stiffness