Total knee arthroplasty (TKA) is a successful treatment of the osteoarthritic knee, which has increased dramatically over the last 30 years. The indication is a painful osteoarthritic knee with relevant radiographic findings and failure of conservative measures like painkillers and exercise. Treatment alternatives are accounted for. Trends today related to surgery are more unicompartmental arthroplasties in case of confined unicompartmental osteoarthritis, an approach as minimal as possible, a modified gap balancing technique, more cruciate retaining arthroplasties, fixed bearings, and - at least in the younger patients - more cementless implants. Trends related to organization are implementation of the fast track concept, which has reduced morbidity and length of stay, and concentration in larger units, which will also decrease morbidity and mortality. An annual volume of >25 TKAs per surgeon seems to positively influence the rate of surgical complications and implant survival. The painful TKA knee should be thoroughly evaluated, but not revised except if a relevant indication can be established. The most frequent indications for revision are: aseptic loosening, instability, infection, malalignment, stiffness and wear. Infection be an increasing problem. New implants should only be introduced stepwise after thorough testing.