Comparison of Limb and Component Alignment Using Computer-Assisted Navigation Versus Image Intensifier–Guided Conventional Total Knee Arthroplasty

Total knee arthroplasty was performed in 282 knees with image-free navigation (group A) and in 185 with optimized conventional technique (group B). Mean postoperative mechanical axis of the limb was 179.7° in group A and 179.1° in group B (P < .002). There was a higher percentage of knees in group A that had restoration of mechanical axis to ±1°, ±2°, and ±3° of neutral (P < .0001). There were 9.2% outliers (±3°) in group A and 21.6% outliers in group B (P < .0001). For knees exceeding 20° varus, there was no significant difference between the mean mechanical axes in the 2 groups. Both components were aligned within 3° of neutral in 90.8% of the knees in group A and 76.2% of the knees in group B (P < .0001).