PURPOSE: In conventional total knee arthroplasty (TKA) using extramedullary alignment guides, it is not always easy to cut the proximal tibia precisely perpendicular to the tibial axis. The purpose of this study was to compare the radiographic accuracy of cutting the proximal tibia between the use of the bony landmarks of the anterior tibial border and the use of the conventional technique. METHODS: A total of 173 patients underwent primary TKA. In 76 TKAs, we used the bony landmark method, and in 97 TKAs, we used the conventional method. In the bony landmark method, we set the coronal alignment in reference to the line connecting the proximal and distal one-third of the anterior tibial border, and we determined the 5° posterior slope in reference to this line. Six months postoperatively, radiological evaluations were performed using full-length standing anteroposterior and lateral radiographs of the knee. RESULTS: No significant differences in the coronal tibial component angle were found between the groups. The posterior tilt of the tibial component was significantly smaller in the bony landmark method than in the conventional method (5.1° ± 2.9° vs. 6.4° ± 3.2°, respectively; p = 0.007). The percentage of patients whose posterior tilt of the tibial component was within ±3° of 5° was significantly larger in the bony landmark method than in the conventional method (70 vs. 62%, respectively; p = 0.04). CONCLUSIONS: The bony landmark method provided a more accurate posterior tibial slope than the conventional method. However, there was no difference in coronal alignment compared with the conventional method.
PURPOSE: In conventional total knee arthroplasty (TKA) using extramedullary alignment guides, it is not always easy to cut the proximal tibia precisely perpendicular to the tibial axis. The purpose of this study was to compare the radiographic accuracy of cutting the proximal tibia between the use of the bony landmarks of the anterior tibial border and the use of the conventional technique. METHODS: A total of 173 patients underwent primary TKA. In 76 TKAs, we used the bony landmark method, and in 97 TKAs, we used the conventional method. In the bony landmark method, we set the coronal alignment in reference to the line connecting the proximal and distal one-third of the anterior tibial border, and we determined the 5° posterior slope in reference to this line. Six months postoperatively, radiological evaluations were performed using full-length standing anteroposterior and lateral radiographs of the knee. RESULTS: No significant differences in the coronal tibial component angle were found between the groups. The posterior tilt of the tibial component was significantly smaller in the bony landmark method than in the conventional method (5.1° ± 2.9° vs. 6.4° ± 3.2°, respectively; p = 0.007). The percentage of patients whose posterior tilt of the tibial component was within ±3° of 5° was significantly larger in the bony landmark method than in the conventional method (70 vs. 62%, respectively; p = 0.04). CONCLUSIONS: The bony landmark method provided a more accurate posterior tibial slope than the conventional method. However, there was no difference in coronal alignment compared with the conventional method.
Authors: John B Meding; Michael E Berend; Merrill A Ritter; Matthew R Galley; Robert A Malinzak Journal: J Arthroplasty Date: 2011-06 Impact factor: 4.757