Adhesive Capsulitis of the Shoulder

Adhesive capsulitis, commonly known as frozen shoulder, is a condition characterised by shoulder pain and stiffness, significantly restricting movement, particularly in external rotation.

The condition entails the loss of voluntary and passive shoulder movement in multiple directions, though the shoulder typically does not hurt significantly when touched. Muscle loss around the shoulder may also occur.

Onset is usually gradual over weeks to months, and complications can include fracture of the humerus or rupture of the biceps tendon.

Signs and Symptoms

Symptoms of adhesive capsulitis include shoulder pain and a limited range of motion, which are common in many shoulder conditions. However, an important hallmark of adhesive capsulitis is the severity of stiffness that can make simple arm movements nearly impossible. The pain is usually dull or aching and may worsen at night and with any motion.

The progression of primary frozen shoulder is often described in three stages:

1. Stage one (Freezing/Painful stage): This stage lasts from six weeks to nine months and involves a slow onset of pain, with worsening pain and a gradual loss of shoulder motion.
2. Stage two (Frozen/Adhesive stage): This stage, lasting four to twelve months, is marked by a slow improvement in pain but persistent stiffness.
3. Stage three (Thawing/Recovery stage): Over a period of 5 to 26 months, shoulder motion gradually returns to normal.

Physical examination typically reveals restricted range of motion in all planes of movement, both active and passive, distinguishing it from conditions like shoulder impingement syndrome or rotator cuff tendinitis, where passive range of motion is usually normal.

Causes

The exact causes of adhesive capsulitis are not well understood, but several factors are associated with higher risk. Secondary adhesive capsulitis can develop after shoulder injury or surgery, leading to prolonged immobility. Primary adhesive capsulitis, also known as idiopathic, occurs without a known trigger and is more common in the non-dominant arm.

Risk factors include systemic conditions like diabetes mellitus, thyroid disease, stroke, lung disease, heart disease, Dupuytren's contracture, and autoimmune diseases. Both type 1 and type 2 diabetes significantly increase the risk.

Pathophysiology

The pathophysiology involves both inflammatory and fibrotic components, primarily the hardening of the shoulder joint capsule due to scar tissue (adhesions). This results in reduced synovial fluid, which normally lubricates the shoulder joint. In stage I, inflammatory cytokines are present in the joint fluid, and the thickening of the coracohumeral ligament significantly limits external and internal rotation.

Diagnosis

Adhesive capsulitis is often a diagnosis of exclusion, based on history and physical exam. A key diagnostic sign is the similarity between the limits of active and passive range of motion, with external rotation being the most restricted movement. Imaging studies like ultrasound and MRI are not required but can help rule out other causes and confirm the diagnosis by showing characteristic features such as thickened coracohumeral ligament and fibrotic changes in the shoulder.

Treatment

Non-surgical management is generally the initial approach, with no strong evidence favouring any specific treatment. Common treatments include NSAIDs, physical therapy, corticosteroids, and shoulder injections. Surgery may be considered for those not improving with conservative measures.

Medication

NSAIDs are used for pain control, and oral steroids may offer short-term benefits. Intra-articular corticosteroid injections are effective for short- and medium-term pain relief and increased range of motion, though the benefits are not long-lasting.

Exercise and Physical Therapy

Shoulder stretching and strengthening exercises improve function and decrease pain. Supervised exercise tends to be more effective than unsupervised home exercises. Techniques like posterior glenohumeral mobilisation and extracorporeal shock wave therapy (ESWT) show promise in improving symptoms.

Surgery

If non-surgical measures fail, surgical options include arthroscopic capsular release and open surgery to address underlying causes of restricted movement. Surgery is typically reserved for severe, prolonged cases.

Prognosis

Adhesive capsulitis is generally self-limiting, resolving within 1 to 3 years, though pain and stiffness may persist in 20 to 50% of individuals. The prevalence is estimated at 2% to 5% of the general population, with higher rates in people with diabetes and other systemic conditions. The condition is more common in women aged 40–60.

---

Self-assessment MCQs (single best answer)

Which of the following is NOT a common risk factor for adhesive capsulitis?

What is the primary characteristic of adhesive capsulitis?

Which stage of adhesive capsulitis is associated with the gradual improvement of pain but persistent stiffness?

What is the typical duration for the Thawing/Recovery stage of adhesive capsulitis?

Which movement is most restricted in adhesive capsulitis?

What imaging study is generally not required but can help confirm the diagnosis of adhesive capsulitis?

Which treatment is NOT typically used in the initial management of adhesive capsulitis?

During which stage does the slow onset of pain with worsening pain and gradual loss of shoulder motion occur?

Which of the following treatments has shown promise in improving symptoms of adhesive capsulitis?

Which of the following is true about the prognosis of adhesive capsulitis?