ASSESSING THE APPLICABILITY OF CPAK CLASSIFICATION IN ROBOTICASSISTED TOTAL KNEE ARTHROPLASTY: ANALYSING ITS ABILITY TO PREDICT SOFT TISSUE BALANCE PREOPERATIVELY, AND DETERMINING ITS COMPARATIVE EFFECTIVENESS BETWEEN KINEMATIC ALIGNMENT (KA) AND MECHANICAL ALIGNMENT (MA).

AIM To assess the applicability of CPAK classification in Robotic-Assisted Total knee Arthroplasty and analyse its ability to predict soft tissue balance preoperatively. To determine the effectiveness of CPAK classification between kinematic alignment (KA) and mechanical alignment (MA). Methods The usefulness of the CPAK classification was evaluated through radiographic study of 540 osteoarthritic (OA) knees. The arithmetic HKA (aHKA), which calculates joint line obliquity (JLO) and constitutional limb alignment, is the basis for nine phenotypes that make up CPAK. In a cohort of 540 robotically assisted TKAs assigned to either KA or MA, intraoperative balance was compared within each phenotype. Descriptive analyses of OA groups according to CPAK type and comparisons of balance at 10° of flexion within each type were the main results. Secondary outcomes evaluated each CPAK type's balance at 45° and 90°. Results CPAK Type I (83.33%) was the most often seen type, followed by Type 3 (5.5%) and Type 9 (11.1%). In our investigation, we did not see the remaining CPAK kinds. In comparison to MA, a higher percentage of KA TKAs across all CPAK types attained optimal balance. In CPAK Type 1 (100% KA vs. 18% MA; p < 0.001), this effect was the greatest and statistically significant, while it was not significant in CPAK Type 3 (71% KA vs. 50% MA). ConclusionBased on JLO and constitutional alignment, CPAK is a thorough classification system for coronal knee alignment that may be used to both healthy and arthritic knees. CPAK determines which knee phenotypes, when soft tissue balance optimization is given priority, may benefit most from KA. It will also make reporting in subsequent trials consistent.