Bursitis
Bursitis
What is a bursa?
  • A bursa is a small fluid filled sac that is located over pressure points between a bony prominence and the overlying skin, tendon or muscle

What is the function of a bursa?
  • The function of a bursa is to reduce the friction between the bony prominence and the overlying structure 

What is knee bursitis?
  • Knee bursitis is inflammation of any of the numerous bursae located around the knee joint 
  • There are approximately 13 bursae around the knee and any of them can become inflamed and cause pain
What are the most common locations for knee bursitis?
  • The four most common bursa that get inflamed are:
    • Suprapatellar: 
      • Located proximal to the patella
    • Prepatellar: 
      • Located over the patella
    • Infrapatellar: 
      • Located distal to the patella
    • Pes Anserine: 
      • Locatedover the pes ansirinus (proximal medial aspect of the tibia anteriorly)
What is the cause of bursitis?
  • Bursitis at the front of the knee commonly occur from repetitive frictional forces and pressure on a bursa at the front of the knee such as those who kneel a lot e.g. carpenters, plumbers, tilers
  • Bursitis at the back of the knee (also known as Baker’s cyst) occurs from fluid accumulation secondary to an injury or arthritis inside the knee
  • Infection of the bursa
  • Excessive activity
  • Conditions that increase fluid inside the knee joint such as osteoarthritis, rheumatoid arthritis and gout
Symptoms
  • Symptoms vary depending on: 
    • location of the affected bursa
    • cause of the bursitis
  • Swelling
  • Pain especially when pressure is applied over the bursa
  • Warmth
Investigations 
  • Blood tests: 
    • Help to differentiate inflammation from infection
  • X-rays:
    • Help identify arthritis or other bone pathology
  • MRI scan:
    • Helps to delineate soft tissue structures better than Xrays
    • Will show dimensions of the bursa and pathology inside the knee which could contribute to the formation of bursitis
  • Aspiration of the fluid:
    • This involves sticking a needle in the bursa and collect some fluid to send it to the lab to investigate its contents and exclude infection
    • It will also help with pain relief
What are the treatment options for bursitis?
  • Conservative:
    • Conservative management is usually all that is indicated:
      • Avoiding friction over the area is key
      • Paracetamol
      • Anti-inflammatories:
        • They help to reduce inflammation and swelling in the knee
      • Rest:
        • This helps to reduce strain on the knee and subsequent swelling
      • Ice:
        • Frequent icing of the knee helps to reduce inflammation and swelling inside the knee
      • Compression with an elastic bandage:
        • Wrapping the knee up with an elastic bandage will help reduce knee swelling
      • Elevation:
        • Elevating the leg will help reduce knee swelling with the help of gravity
      • Aspiration of the bursa will help reduce swelling and pain but has a high chance of recurrence
    • If the bursa is infected need either intravenous or oral antibiotics pending on severity
  • Operative:
    • Rarely indicated:
      • Fluid can reaccumulate so unnecessary exposure to an operation
      • Operative scar has poor history of healing and can cause a chronic discharging sinus 
        • A sinus is a tract that forms between skin and bursa and fluid keeps coming out which then increases the risk of the bursa becoming infected
      • Consider washout and debridement in resistant cases of infected bursitis
Prevention
  • Wear kneepads especially for those who knee a lot (e.g. plumbers, carpenters, bricklayers) as they reduce pressure and friction at the front of the knee
  • Take regular breaks if have to kneel
  • Avoid keeping your knees too flexed
  • Apply ice to knee after period of excessive kneeling and knee squatting
  • Lose weight so as to offload forces in an arthritic knee
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