Limitation of motion after knee arthroplasty can be the result of a multiplicity of factors. Among these are malpositioning of the components, especially in the sagittal plane; oversizing at the patellofemoral or tibiofemoral joint spaces; retaining posterior osteophytes; and persisting with a tight posterior cruciate ligament. Postoperatively, problems with physical therapy likewise can cause limitation of both extension and flexion. Specific patient factors also may affect the range of motion after surgery. Although most patients achieve a postoperative flexion that is highly correlated to that which was present preoperatively, factors such as pain, obesity, and deformities of adjacent joints may limit such motion.