This study aims to compare the clinical results of patella resurfacing or not under subvastus approach in total knee arthroplasty. Even though the excellent results of total knee arthroplasty(TKA), there is persistent controversy over whether or not to replace the patella. Anterior knee pain continued to be a unsolved problem of TKA patients. Some surgeons always performed patella resurfacing during total knee arthroplasty but the others didn't do that. It's up to surgeon's preference. There were several studies of patellar resurfacing or not in TKA. But previous studies almost have been done under other approach, not a subvastus approach.

This study prospectively randomized patients receiving bilateral TKA with patellar resurfacing or not in each knee. Patients preference and clinical results was investigated in both knee of same patients who received patellar resurfacing or not during minimum 2 year follow up.

The primary objective of this work was to compare pain, stiffness and function between groups at minimum 2 year postoperatively. Secondarily, we compared pain, patient preference at minimum 2 year postoperatively. The investigators hypothesized that there would be no difference between the two groups of subjects in the measured outcomes.

Patients receiving TKA were prospectively enrolled before surgery and randomized intraoperatively to either receive patella replacement or not in both knee of same patients. Subjects were assessed pre-operatively and at 6 months, 1, 2 years postoperatively for pain, function, and stiffness using a disease-specific (Western Ontario and McMaster Osteoarthritis Index [WOMAC]) . Other measurements like Knee Society score, Feller's score, Patient satisfaction (VAS) also checked pre-operatively and at 6 months, 1, 2 years postoperatively.

Inclusion Criteria:

• Patients for total knee arthroplasty
• Having medicare insurance

Exclusion Criteria:

• Patients who are not able to cooperate
• Serious deformity (not suitable for a standard TKA prosthesis)
• Patellar thickness less than 18 mm
• Prior operation involving the extensor mechanism
• Rheumatoid arthritis
• Severe medical disability limiting the ability to walk
• Revision surgery
• Knees with predominantly patellofemoral arthrosis