• Bursae are synovial fluid-filled sacs:
    • ∼150 are located between bones, ligaments, tendons, muscles, and skin
  • They provide lubrication to reduce friction during movement
  • Bursitis is inflammation of a bursa caused by trauma and overuse, infection, crystal deposition, or systemic disease
  • Chronic bursitis can lead to proliferative changes in the bursa
  • Commonly affected sites:
    • Shoulder (subacromial)
    • Elbow (olecranon): Usually secondary to trauma
    • Hip (greater trochanter, ischial, iliopsoas): More common in elderly. Of note, trochanteric bursitis is less common than previously thought, more commonly pain is due to abductor tendinopathy
    • Knee (prepatellar and pes anserine): Secondary to trauma or arthritis
    • Foot (calcaneal): Almost always secondary to improperly fitting shoes/heels


  • Trauma (most common cause):
    • Specific traumatic event or repetitive use of associated joints
    • Adjacent tendon tear (e.g., acute shoulder cuff tear)
  • Infection: Secondary to direct penetration; may be obvious or microscopic:
    • Higher risk with diabetes, chronic alcohol abuse, uremia, gout, immunosuppression
    • 90% caused by Staphylococcus spp
  • Crystal deposition: Calcium phosphate, urate
  • Systemic disease: Rheumatoid arthritis, gout, ankylosing spondylitis, psoriatic arthritis, lupus, rheumatic fever

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