What are the common causes of shoulder pain?

Common Causes of Shoulder Pain

Shoulder pain stems primarily from traumatic injuries (fractures and soft tissue damage) in acute presentations, while chronic pain typically arises from rotator cuff disorders, adhesive capsulitis, impingement syndrome, and degenerative joint disease.

Acute Shoulder Pain Causes

Traumatic Etiologies (Most Common in Acute Settings)

Trauma is the predominant cause of acute shoulder pain 1, with the following specific injuries:

Fractures

• Clavicle fractures
• Scapula fractures
• Proximal humerus fractures

These fractures typically result from direct blows or falls onto an outstretched hand 2.

Soft Tissue Injuries

• Rotator cuff tears (including the supraspinatus, infraspinatus, subscapularis, and teres minor)
• Acromioclavicular ligament injuries
• Labroligamentous complex tears

Joint Instability

• Glenohumeral dislocations (most common)
• Acromioclavicular joint sprains/dislocations
• Sternoclavicular joint injuries

Important Clinical Pitfall: Glenohumeral and acromioclavicular joint dislocations can be missed on anterior-posterior radiographs alone, requiring axillary or scapula-Y views for accurate diagnosis 1.

Demographics

Traumatic shoulder pain disproportionately affects young adults and male patients, with incidence varying by age, activity level, and sport participation 1.

Chronic Shoulder Pain Causes

Chronic shoulder pain is defined as pain persisting longer than six months 3 and represents the third most common musculoskeletal complaint after back and neck pain 4.

Primary Chronic Conditions

Rotator Cuff Disorders (≈10% of all shoulder pain)

• Tendinopathy
• Partial tears
• Complete tears

Clinical Decision Rule for Rotator Cuff Tears: Look for pain with overhead activity, weakness on empty can test, weakness on external rotation test, and positive impingement sign 3.

Adhesive Capsulitis (≈6% of all shoulder pain)

• Associated conditions: Diabetes mellitus and thyroid disorders
• Clinical presentation: Diffuse shoulder pain with restricted passive range of motion on examination 3

Impingement Syndrome

A common cause of chronic pain involving compression of rotator cuff tendons beneath the acromion 4.

Glenohumeral Osteoarthritis (≈2-5% of all shoulder pain)

• In patients >50 years: Presents as gradual pain and loss of motion
• In patients <40 years: More likely related to instability with history of dislocation/subluxation events 3

Acromioclavicular Osteoarthritis

• Clinical presentation: Superior shoulder pain, acromioclavicular joint tenderness, and positive cross-body adduction test 3

Biceps Tendonitis

Inflammation of the long head of the biceps tendon causing anterior shoulder pain 2.

Additional Chronic Causes

• Calcific tendinitis 1
• Bursitis 1
• Labral injuries 2
• Cervical radiculopathy (referred pain) 4

Diagnostic Approach Algorithm

Step 1: Determine Acute vs. Chronic

• Acute: Recent trauma or sudden onset
• Chronic: >6 months duration

Step 2: Identify Red Flags for Urgent Management

• Unstable or significantly displaced fractures
• Joint instability requiring reduction
• Massive rotator cuff tears (may require expedited surgical timeline) 1

Step 3: Clinical Examination Focus

• Mechanism of injury (trauma history)
• Age (affects differential diagnosis)
• Activity level and sport participation
• Associated medical conditions (diabetes, thyroid disease for adhesive capsulitis)
• Specific physical examination maneuvers based on suspected diagnosis 3

Step 4: Consider Systemic Causes

• Inflammatory arthritis 1
• Crystalline arthritis 1
• Referred pain from cervical spine

Economic and Clinical Impact

The direct costs for treating shoulder dysfunction in the United States totaled $7 billion in 2000 5, reflecting the substantial societal burden of this condition. The multifactorial nature of shoulder pathology often requires comprehensive evaluation to identify the correct underlying cause, as multiple conditions can coexist 5.

Critical Management Note: Most shoulder pain causes respond to non-surgical treatment including physical therapy, anti-inflammatory medications, and corticosteroid injections 4. However, certain traumatic injuries—particularly unstable fractures, joint instability, and massive rotator cuff tears—require acute surgical intervention to optimize functional outcomes and prevent long-term disability 1.