What Causes Frozen Shoulder? Prevention Tips

The short answer: the exact cause of frozen shoulder is not fully understood, but it happens when the lining (capsule) around the shoulder joint becomes inflamed and then stiff. It is more common in people with diabetes or thyroid conditions, after shoulder surgery or injury, and after a long period of not moving the arm. It most often affects people between 40 and 60.

Frozen shoulder, or adhesive capsulitis, is a common yet often misunderstood condition characterised by pain and significant restriction of shoulder movement. For many, the prospect of not being able to lift a cup of tea or brush your hair can be alarming. Fortunately, by understanding the causes of frozen shoulder and implementing targeted prevention strategies, including the support of an experienced osteopath, you can significantly reduce your risk and maintain optimal shoulder health.

Understanding Frozen Shoulder

Frozen shoulder affects the shoulder joint capsule, causing it to stiffen and tighten. As a result, the shoulder becomes painful, and its range of motion diminishes considerably. Although the exact pathological processes remain under investigation, adhesive capsulitis generally progresses through three stages:

1. Freezing (Painful) Stage: Gradual onset of shoulder pain, worsening over 6–9 months and limiting movement.
2. Frozen (Stiff) Stage: Pain may decrease slightly, but stiffness remains severe, typically lasting 4–6 months.
3. Thawing Stage: Slow improvement in mobility over 6–12 months, as the capsule gradually loosens.

During each phase, everyday activities, such as dressing, driving or reaching for objects, can become increasingly challenging. As a result, seeking early advice from an osteopath can help manage symptoms and prevent long-term stiffness.

Medical Causes of Frozen Shoulder

Frozen shoulder can arise from various medical and physiological factors. Below are some of the most significant contributors:

1. Diabetes Mellitus

People with diabetes are up to five times more likely to develop frozen shoulder than the general population. High blood sugar levels can lead to changes in connective tissue collagen, causing the joint capsule to thicken and lose elasticity.

2. Post-Surgical Immobilisation

After shoulder or chest surgery, such as rotator cuff repair, mastectomy or cardiac procedures, prolonged immobilisation can precipitate adhesive capsulitis. Without regular gentle movement, the capsule can contract around the joint, leading to pain and stiffness.

3. Trauma and Injury

Significant trauma to the shoulder, including fractures, dislocations or soft-tissue tears, can trigger inflammatory responses. Subsequently, scar tissue formation within the joint capsule may limit movement and contribute to adhesive changes.

4. Thyroid Disorders

Both hyperthyroidism and hypothyroidism have been associated with an increased risk of frozen shoulder. Hormonal imbalances can affect collagen metabolism and joint health, making the shoulder capsule more susceptible to adhesive changes.

5. Cardiovascular Disease

Some studies suggest a link between cardiovascular conditions, such as heart disease or stroke, and frozen shoulder. Although the exact mechanism remains unclear, reduced physical activity and vascular changes may play a role.

Lifestyle-Related Causes and Risk Factors

Beyond strictly medical triggers, certain lifestyle factors can raise your risk of developing frozen shoulder. It is therefore crucial to address these proactively:

1. Sedentary Behaviour: Prolonged periods at a desk or in front of a screen can limit shoulder mobility.
2. Poor Posture: Rounded shoulders and forward head carriage place abnormal stress on the shoulder capsule, leading to micro-trauma over time.
3. Smoking: Nicotine impairs microcirculation and tissue healing, potentially exacerbating capsular fibrosis.
4. Obesity: Excess body weight is associated with systemic inflammation and may increase the likelihood of musculoskeletal disorders.

By recognising these risk factors early, you can work with an osteopath to design an exercise and lifestyle programme that targets mobility, posture, and overall health.