Frozen Shoulder (Adhesive Capsulitis)

Definition

Epidemiology & Risk Factors

• Most common between ages 40-70; females more frequently affected
• The nondominant shoulder is more often involved
• Primary (idiopathic) - most cases; no identifiable cause
• Secondary - results from a known cause:
  • Diabetes mellitus (disproportionately common; also predicts worse outcomes)
  • Thyroid disease (hypo- and hyperthyroidism)
  • Prolonged immobilization after trauma, surgery, or stroke
  • Primary shoulder conditions: impingement syndrome, bicipital tendinitis, rotator cuff tear
  • Pulmonary neoplasm, autoimmune disorders
  • Chest or breast surgery
• Psychological factors: depression and anxiety adversely affect symptoms and function
• Miller's Review of Orthopaedics, 9th Ed; Goldman-Cecil Medicine; Tintinalli's Emergency Medicine

Pathophysiology

Clinical Stages

• Tintinalli's Emergency Medicine, p. 2367

Clinical Features

• Insidious onset of diffuse, aching shoulder pain - often after minor trauma or spontaneous
• Pain is worse at night and at rest, especially in early stages
• Pain may radiate down the upper arm; disuse can cause muscle atrophy
• Pathognomonic sign: loss of external rotation (active = passive)
• Later stages: global ROM loss in all planes
• Key point: active ROM and passive ROM are equivalent (distinguishing it from rotator cuff tear)

Differential Diagnosis

1. Glenohumeral osteoarthritis
2. Locked posterior shoulder dislocation

Investigations

• X-rays: Normal (rules out OA, fracture, dislocation)
• Arthrography: Shows loss of the normal axillary recess and reduced joint capsule volume (confirms contracture)
• MRI: Thickening of glenohumeral joint capsule along the axillary pouch, thickening of CHL, obliteration of subcoracoid fat triangle, rotator interval synovitis - but none are pathognomonic; sensitivity ~70%, specificity ~95%
• Ultrasound: Increased vascular flow, thickening of rotator cuff structures

Treatment

Non-operative (first line - ~90% respond)

• Avoid immobilization - do not use a sling beyond short-term pain control, as it worsens capsular restriction
• NSAIDs and analgesics
• Physiotherapy: pendulum exercises, wall-climbing with fingers, progressing to active ROM and strengthening; ice packs, TENS, ultrasound
• Intra-articular corticosteroid injection (methylprednisolone 40 mg/mL, 1 mL into glenohumeral joint ± subacromial bursa): improves pain and function in the short term
• Oral corticosteroids: improve pain and ROM in the short term
• Hydrodistension/distension arthrography: sometimes employed for refractory cases

Operative (after 12-16 weeks of failed conservative treatment)

• Closed manipulation under anesthesia (MUA): good long-term results; full ROM obtained in ~90% of non-diabetic patients vs. ~71% of diabetic patients
• Arthroscopic capsular release: indicated when MUA fails; places the axillary nerve at risk; selective vs. complete release techniques used
• Open capsular release: reserved for failure of arthroscopic release; emphasis on release of the coracohumeral ligament and reestablishment of the rotator interval

Prognosis

• Traditionally considered self-limiting, lasting 12-18 months without long-term sequelae
• About 10% of patients have long-term residual problems
• A 10-year follow-up study showed 94% recovered to normal function without treatment; however, only ~30-51% were entirely pain-free
• Diabetic patients have significantly worse outcomes - results are poorer even with intervention
• Earlier presentation correlates with faster recovery; dominant shoulder involvement predicts a good result
• Campbell's Operative Orthopaedics 15th Ed 2026, p. 8359-8403