Prevalence and Predictors of Post-Operative Coronal Alignment Outliers and Their Association With the Functional Outcomes in Navigated Total Knee Arthroplasty

We aimed to determine the prevalence and predictors for being an outlier after navigated TKA and asked whether navigated TKAs with perfect coronal alignment have better functional outcomes than those without it. Alignment was measured in 124 patients (191 knees) with navigated TKAs who were available for 1 year functional outcome assessment. The outcomes were compared among the 3 subgroups divided by the deviation of mechanical axis from neutral (0°): the perfect, 0° or within 1°; the acceptable, 1°-3°; and the outlier, beyond 3°. The prevalence of outliers was 20.4%, and the severity of preoperative varus deformity was the strongest predictor. Accuracy of coronal alignment in radiographs did not correlate consistently with functional outcomes.