Infection following total knee replacement surgery is a challenging and devastating complication. Clinical assessment including history, examination, radiographs, blood tests and knee aspirations helps to establish the diagnosis. Revision surgery is typically required to eradicate infection and restore function. This has traditionally been performed through two-stage revision surgery, although single-stage revision surgery is gaining popularity with comparable results in carefully selected patients. This article reviews the clinical assessment and principles of surgical management of infected total knee replacements.