Comparison of prosthetic/limb alignment, soft tissue balance, and clinical outcomes between two different prostheses in ground kinematically aligned total knee arthroplasty.

Abstract

Kinematically aligned total knee arthroplasty has gained popularity. This study aimed to evaluate kinematic alignment targeting the neutral ground mechanical axis (ground kinematic alignment) through a comparison between two modern prostheses. This cohort study included 82 consecutive patients (46 Persona® and 36 ATTUNE® prostheses) who underwent unilateral ground kinematically aligned total knee arthroplasty using a portable navigation system for varus osteoarthritis. After 1:1 propensity score matching, 56 patients with comparable demographic data were matched between groups. Patellar orientation, hip-knee-ankle angle, coronal femoral/tibial component alignment, and joint line orientation angle were compared between the groups. Intra-operative patellar tracking and soft tissue balance, including joint component gap and varus/valgus balance, were also compared. At 1 year postoperatively, clinical outcomes, including range of motion and 2011 Knee Society Score, were compared. Radiological parameters including patellar shift and tilt were not significantly different between the groups, however the ratio of intraoperative lateral retinacular release to adjust patellar tracking was significantly higher in the Persona group than in the ATTUNE group. While both groups showed similar pattern of intra-operative soft tissue balance, the ATTUNE group showed a more stable joint component gap in the shallow range of flexion and a smaller lateral laxity in deep flexion than the Persona group (p < 0.05). There were no significant differences in clinical outcomes between the groups. Ground kinematically aligned total knee arthroplasty using Persona or ATTUNE prostheses showed similar intra-operative and postoperative results; however, consideration should also be given to the characteristics between the models.