Comparison of the Limb Alignment and the Component Positioning between Conventional and Navigated Total Knee Arthroplasties for the Osteoarthritic Knees That Have Anatomic Variation

ABSTRACT

PURPOSE: The authors sought to assess the usefulness of navigation as opposed to the conventional method by analyzing the radiographic results obtained from subjects who underwent total knee arthroplasty for knees that were accompanied with anatomic variations. MATERIALS AND METHODS: The study subjects were selected from 53 patients (a total 72 cases 43 were treated by the conventional method and 29 were treated by the navigational method) who exhibited radiographic evidence of distal femoral varus (2degrees). The coronal femoral component angle (alpha) and the coronal tibial component angle (beta) were measured, and the femoral component position in relation to the mechanical axis (theta) and the post-operative weight-bearing mechanical axis difference (MAD) were compared and analyzed. RESULTS: The navigation method showed significant better results in terms of the alpha, theta and MAD (p<0.05). Among the outliers greater than 3degrees, a statistically significant difference was shown only for the MAD (p=0.030). CONCLUSION: Navigation surgery is useful in terms of the femoral component's position in the coronal plane and limb alignment in the osteoarthritic knee that is accompanied by distal femoral varus or proximal tibial varus.