Blood may be taken in some patients before, during and after the operation to check the amount of red and white blood cells, platelets (FBC), the blood clotting, infection markers (CRP), electrolytes (Sodium, Potassium, Magnesium) and the kidney and liver function. If you might require a blood transfusion, a blood sample for group & save may be taken to determine the blood group. Blood is usually taken from a vein at the elbow or the hand.

A bursa is a small fluid-filled sac which helps reduce friction between bones and tendons to allow free movement. There are hundreds of bursae in the body, and they are found around most major joints.