DOS 2018

DOS Kongressen 2018 · 231 Systematic component alignment differences between first and second knee in simultaneous bilateral total knee arthroplasty Christian Bredgaard Jensen, Henrik Husted, Anders Troelsen, Kirill Gromov Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre Background: Previous studies have reported differences in surgical outcome between first and second operated knee in simultaneous bilateral total knee ar- throplasty (SBTKA). Surgical outcome has been related to the alignment of the implanted components. However, potential alignment differences between the first and second knee in SBTKA, and whether any alignment differences can be linked to the specific implant design has not been investigated. Purpose / Aim of Study: To investigate systematic differences in anatomical component alignment between the first and second knee following SBTKA, and to investigate differences related to implant type. Materials and Methods: We identified 38 consecutive patients operated with SBTKA between 2015 and 2017. 19 patients were operated with Persona total knee arthroplasty (TKA) system and 19 were operated with AGC TKA system. Component alignment in the AP and lateral plane was measured on postopera- tive X-rays. Differences between first and second knee were investigated for both implants. Findings / Results: The second knee had an increased overall varus alignment of 0.8 degrees (p=0.044) compared to the first knee. The tibial component of the second knee had an increased varus alignment of 1.2 degrees (p=0.003) compared to the first knee. Systematic differences for overall and tibial varus alignment were present in AGC TKA, but not in Persona TKA, when analysed separately. The number of outliers with respect to the tibiofemoral axis was higher in the second knee in AGC TKA patients only. Conclusions: When operating the left knee first in SBTKA, the right knee and the tibial component was placed in slight varus alignment compared to the left knee. This difference was only present in knees operated with the AGC TKA system. This may be worth noting for surgeons performing SBTKA to increase uniformity between the operated knees. 172.