A partial knee replacement is also known as a partial knee arthroplasty. The surgery involves opening the knee joint through a small incision on the front of the knee. The damaged surfaces of the joint are surgically removed. The joint is then resurfaced with metal and plastic parts. The parts are typically cemented into position. In a partial knee replacement, only one area of the knee is resurfaced and the rest of the knee is left untouched. A surgical robot or computer navigation system is commonly used during this type of procedure. You are allowed to walk immediately after surgery. The surgery is commonly performed as an outpatient and rarely requires a hospital stay.