Snapshot
- A 50-year-old woman presents with progressive shoulder pain for one year. The pain worsens at night, especially when lying on the affected side, and increases with overhead activities. Physical examination reveals pain with abduction and a positive empty can test. She is managed with physical therapy and NSAIDs.
Introduction
Clinical Definition
Rotator cuff syndrome refers to a continuum of shoulder pathology involving the rotator cuff tendons. It progresses from:
- Tendinopathy
- Subacromial impingement
- Partial or full-thickness tendon tears
The condition most commonly affects the supraspinatus tendon.
Anatomy of the Rotator Cuff (SITS)
The rotator cuff muscles stabilize the shoulder by keeping the humeral head centered in the glenoid cavity. All are primarily innervated by C5–C6 nerve roots.
Supraspinatus
- Innervation: Suprascapular nerve
- Function: Initiates arm abduction (first 15°)
- Insertion: Superior facet of the greater tubercle
Infraspinatus
- Innervation: Suprascapular nerve
- Function: External (lateral) rotation of the arm
- Insertion: Posterolateral aspect of the greater tubercle
Teres Minor
- Innervation: Axillary nerve
- Function: External rotation and adduction
- Insertion: Posterolateral aspect of the greater tubercle
Subscapularis
- Innervation: Upper and lower subscapular nerves
- Function: Internal (medial) rotation and adduction
- Insertion: Lesser tubercle
Epidemiology
Most Commonly Affected Tendon
- Supraspinatus
Typical Patient Profile
- Age >40 years
- Repetitive overhead activities
Risk Factors
- Older age
- Smoking (reduced tendon blood flow)
- Repetitive overhead motion
Pathophysiology
Rotator cuff syndrome develops due to repetitive tensile loading and chronic stress.
Tendinopathy
- Caused by overuse and degeneration
- Leads to tendon weakening
Subacromial Impingement
- Compression of rotator cuff tendons between:
- Acromion
- Humeral head
- The supraspinatus tendon and subacromial bursa pass through this space
- A hooked acromion increases impingement risk
Tendon Tears
- Often occur after a fall on an outstretched hand
- More common in patients with pre-existing tendinopathy
Clinical Presentation
Symptoms
- Lateral shoulder pain
- Pain worsened by:
- Overhead activity
- Sleeping on the affected side
- Night pain
- Functional limitation
Key Range of Motion Finding
- Active range of motion limited by pain
- Passive range of motion remains normal
- This distinguishes rotator cuff syndrome from adhesive capsulitis
Physical Examination
Inspection
- Assess deltoid contour and symmetry
- Look for muscle atrophy
Special Tests
Neer Impingement Test
- Passive forward flexion with internal rotation
- Positive: Reproduction of pain
Hawkins–Kennedy Test
- Shoulder and elbow flexed to 90°, followed by passive internal rotation
- Positive: Pain due to subacromial impingement
Painful Arc Test
- Pain during active abduction between 60° and 120°
Empty Can Test (Supraspinatus)
- Arm abducted to 90°, internally rotated (thumbs down)
- Downward resistance applied
- Positive: Pain or weakness
Drop Arm Test
- Inability to smoothly lower the arm
- Suggests supraspinatus tear
Differentiating Tendinopathy vs Tear
| Feature | Tendinopathy / Impingement | Tear |
|---|---|---|
| Pain | Present | May be present |
| Weakness | No | Yes |
| Abduction weakness | — | Supraspinatus tear |
| External rotation weakness | — | Infraspinatus / Teres minor |
| Internal rotation weakness | — | Subscapularis |
Imaging
Radiographs
- Initial imaging for all patients
- May show:
- Decreased subacromial space
- Upward migration of humeral head
MRI
- Gold standard for evaluating rotator cuff tears
- Indicated when:
- Persistent symptoms
- Suspected full-thickness tear
Ultrasound
- Cost-effective and operator-dependent
- Useful for detecting tears
Diagnosis
- Most cases are clinically diagnosed
- Imaging is used to confirm extent and guide management
Differential Diagnosis
Adhesive Capsulitis
- Limitation of both active and passive range of motion
Cervical Radiculopathy
- Shoulder pain worsened by neck movement
Biceps Tendon Rupture
- Sudden pain with “Popeye” deformity
Treatment
Nonoperative Management (First Line)
- Indicated for:
- Tendinopathy
- Impingement
- High surgical risk patients
Includes:
- Activity modification (avoid overhead motion)
- Physical therapy
- NSAIDs
- Subacromial corticosteroid injections
Operative Management
- Indicated for:
- Acute full-thickness tears
- Failure of conservative treatment after 3–6 months
- Delayed repair may lead to:
- Muscle atrophy
- Poor functional outcomes
Complications
- Chronic pain
- Muscle atrophy
- Adhesive capsulitis
- Functional limitation
Prevention
- Avoiding repetitive overhead stress
- Strengthening rotator cuff muscles
- Strengthening scapular stabilizers