Pros and cons of the coronal plane alignment of the knee (CPAK) classification in total knee arthroplasty - a narrative review.

The increasing interest in modern alignment philosophies for total knee arthroplasty has highlighted the need for a more detailed coronal plane alignment classification system to assess preoperative phenotypes and investigate postoperative outcomes. Currently, the two most commonly used classification systems are the functional knee phenotypes (FKP) and the coronal plane alignment of the knee (CPAK) classification. Since its publication in 2021, the CPAK classification has been utilized globally in various knee-related investigations. This study examines the applications of the CPAK classification to date and summarizes its impact on the personalization of knee surgery. The study aims to identify the limitations of current classification systems and to stimulate future research in personalized knee surgery and knee phenotyping.