Shoulder Pain

Basics

Description

  • Shoulder pain commonly affects patients of all ages.
  • Causes include acute trauma, overuse during sports, infection, and activities of everyday living.
  • Age plays an important role in determining the etiology of shoulder pain.
  • Onset and characteristics of pain, mechanism of injury, and limitation in activity or sport narrow the differential diagnosis.

Epidemiology

  • Shoulder pain accounts for 16% of all musculoskeletal (MSK) complaints.
  • The lifetime prevalence of shoulder pain is ~70%.
  • Predominant etiology varies with age:
    • <30 years old: shoulder instability, overuse injuries
    • 30 to 60 years old: rotator cuff (RTC) disorder, impingement syndrome, partial tears
    • >60 years old: full-thickness tear, glenohumeral OA

Incidence
The incidence of shoulder pain is 7 to 25 cases per 1,000 patients, with a peak incidence in the 4th to 6th decades of life.

Etiology and Pathophysiology

Pathology varies with cause:

  • Trauma—fracture, dislocation, ligament/tendon tear, acromioclavicular (AC) separation
  • Overuse—RTC pathology, biceps tenosynovitis, bursitis, muscle strain, apophyseal injuries, labral injuries
  • RTC disorders most commonly result from repetitive overhead activity, leading to RTC impingement with a three-stage progression:
    • Stage I: tendinopathy
    • Stage II: partial RTC tear
    • Stage III: full-thickness RTC tear
  • Subacromial bursitis can occur with RTC disorders but is rarely an isolated diagnosis.
  • Age related: In pediatric athletes, instability and physeal injuries are more common. With increasing age, the incidence of AC and glenohumeral joint OA, adhesive capsulitis, and RTC tear rises.
  • Rheumatologic: rheumatoid arthritis, polymyalgia rheumatica, fibromyalgia
  • Infectious: septic arthritis
  • Referred pain: neck, gallbladder, diaphragm

Risk Factors

  • Repetitive overhead activity
  • Overhead and upper extremity weight-bearing sports (baseball, softball, swimming, tennis, volleyball)
  • Weight lifting: AC joint disorders
  • Rapid increases in training frequency or load (often associated with improper technique)
  • Muscle weakness or imbalance
  • Trauma or fall onto the shoulder
  • Diabetes, thyroid disorders and other autoimmune diseases, female gender, and ages 40 to 60 years are the risk factors for adhesive capsulitis.

General Prevention

  • Maintain strength and range of motion (ROM).
  • Avoid repetitive overhead activities such as pitch counts in younger baseball athletes.
  • Proper technique (pitching, weight lifting)

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