The investigators asked: (1) Do computer-assisted total knee arthroplasty (TKAs) provide better alignment and clinical function? (2) Do computer-assisted TKAs provide better survivorship of implants and less complication? and (3) Do correction of the mechanical axis of the lower limb to within 3° of neutral is a prognostic marker for late revision surgery due to aseptic loosening?

Computer-assisted total knee arthroplasty (TKA) is reported to improve the overall accuracy of positioning of the femoral and tibia components. However, an acceptable target for alignment remains a matter for debate. A mechanical axis within 3° of neutral axis has been used as the primary outcome measure in many clinical trials comparing computer-assisted- and conventional TKA. However, the evidence supporting this arbitrary value is unreliable because previous reports are limited by their small sample size, inadequate radiographs, short follow-up and lack of clarity when defining a margin of accuracy.

Inclusion Criteria:

• End stage osteoarthritis of the knee joint who require total knee arthroplasty with bilateral lesions.

Exclusion Criteria:

• Inflammatory disease
• patient with other Lower extremity disease which may affect functional outcome
• Neurologic disease effecting patients lower extremity
• Revision surgery
• Patient not medically cleared for bilateral surgery