Does frozen shoulder always follow the classic capsular pattern?

Frozen Shoulder and the Capsular Pattern

No, frozen shoulder does not always follow the classic capsular pattern, though it commonly does in most cases. The capsular pattern typically presents as greater limitation in external rotation, followed by abduction and then internal rotation, but variations can occur based on etiology and individual factors 1.

Understanding Frozen Shoulder (Adhesive Capsulitis)

Frozen shoulder is characterized by:

• Gradual onset of shoulder pain and progressive limitation in glenohumeral joint range of motion 2
• Pathological process involving synovial inflammation followed by capsular fibrosis 3
• High incidence (up to 72%) in certain populations, such as stroke patients 1

Typical Presentation and Patterns

• The classic capsular pattern involves greatest limitation in external rotation, followed by abduction, and then internal rotation 1
• Progression typically occurs through three distinct phases:
  • Freezing (painful) phase
  • Frozen (adhesive) phase
  • Thawing phase 2, 4

Variations in Presentation

Several factors can influence whether a frozen shoulder follows the classic capsular pattern:

• Etiology: Different causes of frozen shoulder can present with variations in the capsular pattern 5

  • Idiopathic cases (primary frozen shoulder) more commonly follow the classic pattern 5
  • Secondary frozen shoulder (post-operative, post-traumatic, or associated with systemic conditions) may present with atypical patterns 2, 5

• Individual factors: Patient-specific characteristics that can affect presentation include:

  • Pre-existing shoulder conditions 1
  • Severity of inflammation 2
  • Duration of symptoms before treatment 3

Diagnostic Considerations

• MRI without contrast is often preferred for evaluating frozen shoulder as it can assess both bony morphology and soft tissue pathology 1
• Range of lateral rotation has been identified as the factor most significantly related to shoulder pain onset 1
• Physical examination typically reveals limitation in both active and passive range of motion 2

Treatment Implications

The variation in capsular patterns has important treatment implications:

• Physical therapy approach: Should be tailored based on the specific pattern of limitation 6, 4

  • Focus on external rotation and abduction movements is particularly important 1
  • Avoid overhead pulleys as they encourage uncontrolled abduction 1

• Intervention selection: Different patterns may respond better to specific treatments 6, 2

  • Intra-articular corticosteroid injections show significant short-term benefits 1, 2
  • Functional electrical stimulation may improve shoulder lateral rotation 1
  • Arthroscopic capsular release may be more successful in idiopathic cases than secondary cases 5

Clinical Pearls

• Early intervention is crucial to prevent progression to a more severe frozen shoulder 6
• Avoiding immobilization (such as arm slings) can help prevent frozen shoulder development 1
• Patient education on proper positioning and movement can prevent further complications 1, 6
• Patients with idiopathic frozen shoulder tend to have better outcomes after arthroscopic capsular release compared to those with secondary causes 5