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For further information, see CMDT Part 41-04: Upper Extremity Musculoskeletal Injuries

Key Features

Essentials of Diagnosis

  • Often occur around bony prominences where it is important to reduce friction

  • Typically presents with locals swelling, which is painful acutely

  • Septic bursitis can present without fever or systemic signs

General Considerations

  • Inflammation of bursae may be secondary to

    • Trauma

    • Infection; most cases are caused by Staphylococcus aureus

    • Arthritic conditions, such as gout, rheumatoid arthritis, or osteoarthritis

  • The two common sites are the olecranon and prepatellar bursae

  • Others sites include

    • Subdeltoid bursa

    • Ischial bursa

    • Trochanteric bursa

    • Semimembranous-gastrocnemius (Baker cyst) bursa

  • Bursitis can be septic or aseptic

Clinical Findings

Symptoms and Signs

  • Tenderness, erythema and warmth, cellulitis

  • Range of motion not affected

  • Absence of fever does not exclude infection; one-third of those with septic olecranon bursitis are afebrile

  • Bursa can become symptomatic when it ruptures; this is particularly true for Baker cyst, which can cause calf pain and swelling that mimics thrombophlebitis


Laboratory Findings

  • Acute swelling and redness calls for aspiration to rule out infection

    • A bursal fluid white blood cell count of > 1000/mcL (1 × 109/L) indicates inflammation from infection, rheumatoid arthritis, or gout

    • The bursal fluid of septic bursitis characteristically contains

      • A purulent aspirate

      • Fluid-to-serum glucose ratio < 50%

      • White cell count > 3000 cells/mcL (3 × 109/L)

      • Polymorphonuclear cells > 50%

      • Positive Gram stain for bacteria

    • Gram stain is positive for S aureus in two-thirds of cases


  • Unnecessary unless there is concern for osteomyelitis, trauma or other underlying pathology

  • Ultrasonography or MRI easily show a ruptured Baker cyst; imaging a presumed Baker cyst can exclude deep venous thrombosis


  • For bursitis caused by trauma

    • Local heat

    • Rest

    • NSAIDs

    • Local corticosteroid injections

  • For ruptured Baker cyst

    • Rest

    • Leg elevation

    • Injection of triamcinolone, 20–40 mg into the knee anteriorly (the knee compartment communicates with the cyst)

  • Aspiration for chronic, stable olecranon bursa swelling usually not required

    • Runs the risk of creating a chronic drainage site, which can be reduced by using a "zig-zag" approach with a small needle (25-gauge if possible) and pulling the skin over the bursa before introducing it

    • Applying a pressure bandage may also help prevent chronic drainage

Therapeutic Procedures

  • For septic bursitis

    • Incision and drainage

    • Antibiotics, usually delivered intravenously, especially against S aureus



  • Avoid resting the elbow on a hard surface or wearing an elbow pad to eliminate repetitive minor trauma to the olecranon bursa

When to Refer

  • Surgical ...

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