If a Knee is infected the patient is first given antibiotics. If the infection does not clear up, the implant will have to be taken out and the patient is scheduled for revision surgery. The original components are removed and a block of polyethylene cement treated with antibiotics (known as a “spacer block”) is inserted into the Knee joint for six weeks. During this time the patient is also treated with intravenous (I.V.) antibiotics. After a minimum of six weeks, new Knee components are implanted.