Beyond Coronal Plane Alignment of the Knee: Similarity and Variability of Extension Knee Balance Across Coronal Plane Alignment of the Knee Phenotypes.

Background: The Coronal Plane Alignment of the Knee (CPAK) classification has been proposed to guide the alignment strategy in total knee arthroplasty (TKA). However, the classification does not take into account the variability of the soft-tissue envelope unique to each knee. The purpose of our study was to determine the variability and similarity of extension balance across each CPAK phenotype.