rotator cuff tendonitis; impingement syndrome; painful arc syndrome; subacromial pain syndrome

Introduction

The major cause of shoulder pain.

Etiology

• repetitive impingement on the tendon(s) forming the rotator cuff
  • the supraspinatus tendon is most often affected
    • impingement between the humeral head & the coracoacromial arch
    • impingement syndrome
  • the tendon of the infraspinatus or the long head of the biceps are less commonly involved

Epidemiology

• individuals over 40 are especially susceptible
• asoociated with baseball, tennis & swimming
• occupations requiring repeated elevation of the arms

Pathology

• edema & hemorrhage of the rotator cuff
• fibrotic thickening & rotator cuff degeneration
• tendon tears & bone spurs
• subacromial bursitis
• degeneration of the supraspinatus if torn

Clinical manifestations

• symptoms generally appear after overuse or injury
• dull aching in shoulder that may interfere with sleep
  • often worse when lying on affected side
• severe pain when arm is actively abducted overhead; lateral deltoid pain aggravated by reaching
• movement in range of 60-120 degrees is especially painful
  • passive abduction of the arm may or may not be painful
• tenderness over the lateral aspect of the humeral head just below the acromion
• pain, weakness of abduction & external rotation of the shoulder with supraspinatus tendon tear
• pain may radiate down arm into forearm
• may be wasting of deltoid & supraspinatus muscles
• active range of motion impaired > passive range of motion*
• pain aggravated by overhead reaching
• positive impingement signs
  • pain with passive internal rotation & forward flexion of the shoulder
  • pain with internal rotation & forward-flexing of the shoulder & while passively flexing the elbow & shoulder to 90 degrees
• normal strength of rotator cuff muscles
• Neer test & Hawkins test often positive
• supraspinatus test (drop arm test)

* contrast to adhesive capsulitis where both active & passive range of motion are impaired

Radiology

generally not needed

• indications
  • suspected full thickness rotator cuff tear
  • diagnostic uncertainty
• X-ray of shoulder may show narrowing of space between the humeral head & undersurface of acromion
  • a space < 8 mm suggests rotator cuff tear
• arthrogram
• ultrasound

Complications

• the supraspinatus tendon may be torn by falling on an outstreched arm or lifting a heavy object

Differential diagnosis

• radiculopathy of cervical spine
• acromio-clavicular (AC) arthritis
  • pain at AC joint intensified with abduction beyond 100 degrees
• rotator cuff test is suggested by positive supraspinatus test

Management

• identify & eliminate provocative activities
• a brief period of rest may be helpful
• acetaminophen or non-steroidal anti-inflammatory drugs (NSAIDs)
• physical therapy
  • restoration of range of motion
  • range of motion daily to prevent adhesive capsulitis
  • wall walking
  • specific exercises & strengthening maneuvers involving the rotator cuff & scapula-stabilizing muscles, using external loads is superior to range of motion exercises
  • insufficient evidence for clinical effectiveness of physical therapy
• glucocorticoid injection into subacromial bursa
  • anterior & lateral approach better than posterior approach
  • benefit at 8 weeks but not at 1 year
• one year outcomes for glucocorticoid injection similar to physical therapy
• immoblization with a sling may increase risk for adhesive capsulitis
• surgery for supraspinatus tendon tear
• Subacromial decompression surgery should not be offered to patients with atraumatic rotator cuff tendonitis

More general terms

• tendonitis (tendon injury)
• repetitive strain disorder
• rotator cuff disease

Additional terms

• rotator cuff impingement test/sign
• rotator cuff tear
• rotator cuff; musculotendinous cuff
• shoulder pain