Total knee arthroplasty

The figures illustrate total knee replacement. A vertical incision is made across the knee joint anteriorly (A) to gain access to the patella. The incision (placement, length) varies depending upon the specific surgical approach. With the approach shown here, once exposed, the patella is rotated away from the joint and the distal femur is exposed. The damaged cartilage and bone are debrided. The femoral condyles are then resurfaced to accommodate the chosen knee prosthesis (B). The femoral component is attached to the femur using either bone cement to seal it into place, or by using a press fit method, depending upon the type of prosthesis. In a similar manner, damaged cartilage and bone are debrided from the tibial plateau, which is then shaped to accommodate the tibial components (tibial tray, spacer) (C). The tibial tray is attached to the bone directly and the spacer is attached to it to allow the knee to bend smoothly. Once the knee prosthesis is in place, the undersurface of the patella is flattened and a polyethylene button is placed between it and the femoral component (D) also to ensure smooth knee function. Once everything is in place, the patella is rotated back to its anterior position, the proper functioning of the completed knee replacement (E) is checked. The incision is then closed and the knee bandaged.