How can one clinically differentiate a supraspinatus tendon tear from adhesive capsulitis?

Clinical Differentiation of Supraspinatus Tear from Adhesive Capsulitis

The key clinical distinction is that adhesive capsulitis demonstrates global restriction of both active AND passive glenohumeral motion in all planes, while supraspinatus tears show preserved passive range of motion with weakness and pain primarily during active abduction and external rotation. 1, 2

Range of Motion Assessment

Passive Range of Motion (Critical Distinguishing Feature)

• Adhesive capsulitis: Demonstrates marked restriction of passive motion in all directions, particularly external rotation with the arm at the side (most sensitive finding) 1, 2
• Supraspinatus tear: Passive range of motion remains normal or near-normal; the examiner can move the shoulder through full range without capsular restriction 3

Active Range of Motion

• Adhesive capsulitis: Active motion is limited equally to passive motion due to capsular contracture 1, 2
• Supraspinatus tear: Active abduction is limited by pain and weakness, but passive motion is preserved 4

Specific Physical Examination Tests

For Supraspinatus Pathology

• Empty can test: Pain or weakness with resisted abduction at 90° in the scapular plane with internal rotation (sensitivity 92% for impingement) 3, 5
• Full can test: Superior diagnostic accuracy compared to empty can test when muscle weakness is the primary criterion 5
• Hawkins' test: Pain with forcible internal rotation at 90° forward flexion (92% sensitive, 25% specific) 3
• Neer's test: Pain with full forward flexion between 70-120° (88% sensitive, 33% specific) 3
• Interpretation: Muscle weakness (not just pain) provides the best diagnostic precision for supraspinatus tears 5

Clinical Presentation Patterns

Supraspinatus tear characteristics:

• Pain during specific phases of throwing or overhead activities (release, deceleration, follow-through phases) 4
• Focal weakness with decreased range during active abduction with external or internal rotation 4
• Pain most apparent with humerus simultaneously abducted and internally rotated 3
• History of repetitive overhead activities or acute trauma 3

Adhesive capsulitis characteristics:

• Painful, gradual loss of motion in all planes without specific trauma 1, 2
• Progressive stages: freezing phase (increasing pain, decreasing motion), frozen phase (less pain, severely restricted motion), thawing phase (gradual improvement) 6, 2
• Predominantly affects middle-aged women (mean age 66 years) 7
• Night pain is common and often severe 2

Critical Diagnostic Algorithm

1. First: Assess passive external rotation with arm at side

   • If severely restricted: strongly suggests adhesive capsulitis 1, 2
   • If normal: proceed to active motion testing

2. Second: Compare active vs. passive motion

   • If both equally restricted in all planes: adhesive capsulitis 1, 2
   • If active motion limited but passive preserved: rotator cuff pathology 4

3. Third: Perform combination of empty can, full can, and zero-degree abduction tests

   • Best diagnostic accuracy when using ≥3 tests together (AUC 0.795) 5
   • Interpret based on weakness rather than pain alone 5

Important Clinical Pitfalls

Overlapping Conditions

• Approximately 61.7% of patients with presumed stage-2 adhesive capsulitis have concurrent supraspinatus pathology on MRI 7
• 30.9% have partial-thickness tears and 7.4% have small full-thickness tears coexisting with adhesive capsulitis 7
• Patients >60 years with adhesive capsulitis have higher prevalence of rotator cuff tears 7

When Clinical Examination is Insufficient

Imaging indications:

• When passive motion restriction is present but history/examination atypical for primary adhesive capsulitis 1, 2
• To exclude alternative pathology (calcific tendinitis, glenohumeral arthropathy, full-thickness rotator cuff tears) 2, 8
• MRI or ultrasound are equivalent first-line imaging modalities 9

Secondary Adhesive Capsulitis

• Can develop following rotator cuff tears, creating diagnostic confusion 10
• Humeral segment joint capsule thickness at axillary recess >4.6mm suggests primary adhesive capsulitis (70.8% sensitivity, 87.3% specificity) versus secondary adhesive capsulitis from supraspinatus tear 10
• Requires imaging to differentiate when both conditions suspected 7, 10

Key Distinguishing Features Summary

Feature	Supraspinatus Tear	Adhesive Capsulitis
Passive ROM	Normal/near-normal [4]	Globally restricted [1,2]
Active ROM	Limited by weakness/pain [4]	Equally limited as passive [1,2]
External rotation restriction	Minimal unless massive tear [4]	Severe, especially with arm at side [1,2]
Pain pattern	Activity-related, specific positions [4]	Constant, worse at night [2]
Weakness on testing	Present with resistance [4,5]	Difficult to assess due to pain/stiffness [1]