Coronal alignment classes after robotic-assisted total knee arthroplasty are not associated with variation in patient- reported outcome measurements: A single-center cohort study

Background: The aims of this study were (1) to use three-dimensional computed tomogra-phy (3DCT) measurements to determine whether patients undergoing imageless robotic-assisted total knee arthroplasty (RA-TKA) develop a variety of postoperative distal femoral mechanical angle (FMA), proximal tibial mechanical angle (TMA), and hip-knee-ankle angle (HKA) phenotypes as described by Hirschmann et al, and (2) to compare postopera-tive patient-reported outcome measurements (PROMs) between these phenotypes.Method: Fifty patients with knee osteoarthritis underwent RA-TKA. All surgeries were per-formed using bicruciate-stabilized TKA. In each case, the postoperative HKA, FMA and TMA were classified into one of Hirschmann's five FMA, five TMA, and seven HKA phenotype cat-egories. We investigated how these phenotypes affected patient satisfaction, 2011 Knee Society Score (KSS) subscale scores, the Forgotten Joint Score-12 (FJS-12) score, and patella scores with anterior knee pain at a mean of 15.1 months after RA-TKA.Results: Coronal alignment angles were assigned to three FMA, four TMA, and five HKA phenotypes. The most common FMA, TMA, and HKA phenotypes were valgus FMA 3 degrees (58%), valgus TMA 3 degrees (60%), and varus HKA 3 degrees (38%). The FMA, TMA, and HKA phenotypes showed no significant differences in any PROMs.Conclusions: RA-TKA led to various HKA, FMA and TMA phenotypes in the coronal plane, none of which affected PROMs. C) 2023 Elsevier B.V. All rights reserved.