Surgical procedure
All patients were administered general anesthesia. All surgical procedures were performed by the same senior knee surgeon (Dr. LB C) who is experienced in the instrumentation and use of the cement PS prosthesis (Genesis II, Smith & Nephew Inc., Memphis, TN, USA). The inflation pressure of the tourniquet was 300 mm Hg. The procedure was performed via a midline skin incision and a medial parapatellar approach to the knee. The cruciate ligaments were excised. Intramedullary and extramedullary alignments were used for the femur and tibia, respectively. Appropriate soft-tissue procedures to realign the knee were performed in both groups. The patella was not resurfaced in all cases but was reshaped to better match the femoral component trochlea if necessary. Denervation was performed by using electrocautery of the patellar rim.