Introduction

Olecranon bursitis describes inflammation of the olecranon bursa, the fluid-filled sac overlying the olecranon process at the proximal end of the ulna. This bursa exists to reduce friction between the posterior aspect of the elbow joint and the overlying soft tissues. Inflammation may result from trauma, infection, or systemic conditions such as rheumatoid arthritis or gout. Olecranon bursitis is also known as 'student's elbow' because the repetitive mild trauma of leaning on a desk using the elbows is a common cause. It is categorised as septic or non-septic depending on whether an infection is present.

Epidemiology

  • Incidence: 500.00 cases per 100,000 person-years
  • Peak incidence: 30-40 years
  • Sex ratio: more common in males 1.5:1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Aetiology

Causes
  • Repetitive trauma (29%) - writers and students leaning on elbows, plumbers, miners
  • Direct trauma (17%)
  • Infection (33%) - 50% of cases occur in immunosuppressed patients (alcohol abuse, diabetes, taking steroids, renal failure, malignancy). 90% of cases due to Staphylococcus aureus.
  • Gout (7%)
  • Rheumatoid arthritis (5%)
  • Idiopathic (5%)

Clinical features

Patients with non-septic olecranon bursitis typically present with a subacute onset of:
  • swelling over the olecranon process (100%)
For many patients, this will be the only symptom. Some patients with non-septic olecranon bursitis also complain of:
  • tenderness over the bursa (45%)
  • erythema over the bursa (25%)
Patients with septic bursitis are more likely to have pain and fever:
-tenderness over the bursa (92-100%)
-fever (40%)

Signs:
  • Swelling over the posterior aspect of the elbow, usually fluctuant and well-circumscribed, appearing over hours to days4
  • Tenderness on palpation of the swollen area
  • Redness and warmth of the overlying skin
  • Fever
  • Skin abrasion overlying the bursa
  • Effusions in other joints if associated with rheumatoid arthritis
  • Tophi if associated with gout

Movement at the elbow joint should be painless until the swollen bursa is compressed in full flexion.

Investigations

Investigations:
  • Not always needed if a clinical diagnosis can be made and there is no concern about septic arthritis, e.g. a well patient without pain, fever or erythema of the bursa.
  • Aspiration of bursal fluid for microscopy (Gram stain and crystals) and culture is essential if septic bursitis is considered. Purulent fluid suggests infection whereas straw-coloured bursal fluid favours a non-infective cause.