Comparative analysis for radiographic measurement of component position between conventional and Navigation assisted Total Knee Arthroplasty

ABSTRACT

PURPOSE: To evaluate usefulness of Navigation system by comparing the radiographic results of femoral and tibial component position between conventional total knee replacement (TKA) and Navigation-assisted TKA. MATERIALS AND METHODS: From December 2003 to January 2006, TKA with Scorpio(R)(Osteonics, NJ,USA) were preformed for 53 knees of 41 patients. Among them, 26 knees (Group A) were operated by conventional TKA and 27 knees (Group B) were by Navigation-assisted TKA. We measured the femorotibial angle (omega), femoral component coronal (alpha) and sagittal angle(gamma), tibial component coronal (beta) and sagittal angle (delta) according to the radiographic evaluation of American Knee Society. We also measured the coronal femoral component angle to the femoral mechanical axis (theta) and femoro-tibial mechanical axis. RESULTS: alpha, omega and thetaangle showed no significant difference between two groups (p>0.05). beta, gammaand delta angle were 89.2+/-1.9, 4.3+/-1.7, 81.4+/-2.9 degree in group A and 90.5+/-1.2, 2.8+/-1.6, 86.6+/-2.2 degree in group B, respectively. There was statistically significant difference in beta, gammaand deltaangle (p<0.05). The range of deviation from desired angle showed no significant difference in femoro-tibial mechanical axis and betaangle. However, there was statistically significant difference in thetaangle with more accuracy in group B (p=0.0001) CONCLUSION: There were statistically significant differences in betaand gammaangle between conventional TKA and Navigation assisted TKA. We could get more accurate femoral component coronal angle to the mechanical axis with the Navigation system.