Clinical Application Of Computer Navigation-assisted Total Knee Arthroplasty

Purpose: To discuss the preliminary clinical results with computer navigationassisted invasive total knee replacement, and analyze the differences of clinical results between CAS and routine NCAS.Material and method: From October of 2006 to October of 2008, 40 cases (49joints) were performed with TKA. They were recruited into this prosective study according to entry criteria and were randomly selected. 20 cases (25 joints) of TKA in Group I which were performed utilizing computer assisted imaging guidance system(CAS) and there were 5 males and 15 females with an average age of 66.7 years. 20 cases (24 joints) of TKA in Group II which were performed with conventional method previously (NCAS) and there were 7 males and 13 females with an average age of 65. 3 years. They were the same with Incision length and Surgical approach. All of them were the first of TKA. The differences between two groups in clinical results, mechanical axes, soft- tissues balance, coincidence, blood loss, KSS scores and operating time were statistically analyzed, and radiographic alignment and prosthesis position of these patients were also analyzed.Results: All cases were followed from 6 to 12 months, for an average of 9months. Between two group, the blood loss were 360.6±36. 6ml and380. 2±40. 2ml; the blood loss in first 24 hours were 380.9±121. 3ml and 410. 3±120. 6ml; The surgery time was 84. 2±11.8min and 58.4±11. 6min; The mechanical axes error was 4.39±1.15 degrees and 2.17±0.27 degrees. The mechanical axes error was 2- 3 degrees in CAS group and 3-6 degrees in NCAS group. Soft- tissues balance angle was 1.10±0.14 degrees and 2.95±0.57 degrees. They were within 2 degree in CAS group and 2- 4 degrees in NCAS group. The distance variable was 3.45±0.71 mm and 6.14±0. 82mm. The distance variable was 2-4 mm in CAS group and 5-7 mm in NCAS group. There were significant differences (P<0. 05) in following parameters between two groups. Radiographic examination showed that the mFTA of control groups was 1.78±1.54 degrees and that of navigation assisted group was 0.87 ±0.97 degrees with significant difference(P<0.05) between these two groups.Conclusion: Utilizing computer assisted imaging guidance in TKA can improvemechanical alignment, component position and better soft- tissues balance. The precise and repeatability could be ensured.