Comparison of Results of Total Knee Arthroplasty Performed Using the Navigation System and the Conventional Technique: Minimal Follow-Up of 5 Years / 대한정형외과학회잡지

ABSTRACT

PURPOSE: Authors compared the laxity, radiologic and clinical outcomes of total knee arthroplasty (TKA) performed using the navigation system and using the conventional technique at least 5-year follow-up. MATERIALS AND METHODS: Total of 92 TKAs were included for this study. Forty seven TKAs were performed by the navigation group and 45 TKAs were performed by the conventional surgery. At the final follow up, to evaluate knee joint laxity, varus-valgus laxities were measured on the stress radiographs taken with varus or valgus loads at 90degrees of flexion. The radiologic measurements and the clinical evaluations were compared between two groups. RESULTS: At the final follow-up, the mean of valgus laxities were 3.9degrees in the navigation group and 4.0degrees in the conventional group, and the corresponding mean of varus laxities were 4.0degrees and 4.3degrees (p=0.19, p=0.22) at 90degrees flexion state. Although there was no significant difference in the total laxities (7.8degrees in the navigation group and 8.1degrees in the conventional group, p=0.35). However, more than 10degrees of total laxity was significantly reduced in the navigation group (1 knee in the navigation group and 6 knees in the conventional group, p=0.04). The outlier numbers at mechanical axis, the mean of coronal inclination of the femoral and tibial component and the mean of sagittal inclination of the femoral and tibial component in the two groups were significantly different. Stiffness of WOMAC score was significantly better in the navigation than in the conventional group (p<0.001). CONCLUSION: Varus-valgus laxity was significantly different in the two groups as were the outlier numbers. The navigation system could provide good, improved alignment accuracy of the lower extremity and better result in stiffness of knee compared with conventional technique.