1. Prospective follow-up and comparative analysis of early, midterm, and long-term surgical results and complications between navigation assisted TKA and conventional TKA.
2. Prospective comparative analysis of cytokines (including ICAM, VCAM, and PECAM) from blood, tissues, and drainage between navigation assisted TKA and conventional TKA.
3. Prospective follow-up of surgical results of navigation-assisted TKA.

Total knee arthroplasty (TKA) is one of the most successful surgery in orthopaedic field. However, occasional outliner from perfect alignment after prosthesis implantation and unavoidable complications are still concerns. The usage of navigation-assisted system on total knee arthroplasty has provided better accuracy of the component alignment and quantity in knee kinematics, which theoretically affords better and consistent functional outcome.

In addition to better alignment, the design of navigation system avoids violation of the medullary canal. This less invasive environment might be contributable to the less blood loss in the drainage bottle, less blood transfusion more stable hemodynamic status, fewer hospitalization days, and fewer complications.

Systemic emboli phenomena during preparation of the femur and tibia are well recognized during total knee arthroplasty. They are widely believed to be the cause of intraoperative hypotension and reduced cardiac output, which may lead to circulatory collapse, change of mental status or cerebral infarction. Kalairajah et al reported that navigation-assisted total knee arthroplasty, when compared with conventional jig-based surgery, significantly reduces systemic emboli as detected by transcranial Doppler ultrasonography. Church et al undertook a prospective, double-blind, randomized study to compare the cardiac emboli load by tranesophageal echocardiography and demonstrated that computer-assisted TKA resulted in the release of significant fewer systemic emboli than the conventional procedure using intramedullary alignment. The increased blood loss in conventional TKA may be due to intramedullary jigging of both femur and tibia, bleeding from sinusoids at the cut cancellous bone surfaces with continuous suction drainage and more soft tissue dissection during balancing of the prosthesis. The investigators have underwent more than 730 computer-assisted TKA since 2005. The investigators data shows less bleeding and fewer transfusion after navigation assisted TKA. The investigators wish to further follow-up and delineate the differential clinical outcomes and perioperative markers (including ICAM, VCAM, and PECAM and other cytokines )between computer-assisted TKA and conventional TKA.

Inclusion Criteria:

• degenerative osteoarthritis of the knee

Exclusion Criteria:

• autoimmune diseases, rheumatoid arthritis, malignancies, previous knee surgery or post-traumatic arthritis

All the patients were recruited from the patient undergoing scheduled total knee arthroplasty in our hospitals (Chang Gung Memorial Hospital, Kaohsiung medical center).