title: Knee awareness and functionality after simultaneous bilateral vs unilateral total knee arthroplasty.
abstract: OBJECTIVE
  To investigate knee awareness and functional outcomes in patients treated with simultaneous bilateral vs unilateral total knee arthroplasty (TKA).
  
  
  METHODS
  Through a database search, we identified 210 patients who had undergone unilateral TKA (UTKA) and 65 patients who had undergone simultaneous bilateral TKA (SBTKA) at our institution between 2010 and 2012. All TKAs were cemented and cruciate retaining. The mean follow-up period was 3.2 (2 to 4) years. All the patients had symptomatic and debilitating unilateral or bilateral osteoarthritis for which all conservative and non-surgical treatments were failed, thus preoperatively the patients had poor functionality. All patients were asked to complete Forgotten Joint Score (FJS) and Oxford Knee Score (OKS) questionnaires. The patients were matched according to age, gender, year of surgery, Kellgren-Lawrence score and pre- and postoperative overall knee alignment. The FJS and OKS questionnaire results of the two groups were then compared.
  
  
  RESULTS
  A mixed-effects model was used to analyze differences between SBTKA and UTKA. OKS: The mean difference in the OKS between the patients who had undergone SBTKA and those who had undergone UTKA was 1.5, which was not statistically significant (CI = -0.9:4.0, P-value = 0.228). The mean OKS of the SBTKA patients was 37.6 (SD = 9.0), and the mean OKS of the UTKA patients was 36.1 (SD = 9.9). FJS: The mean difference in the FJS between the patients who had undergone SBTKA and those who had undergone UTKA was 2.3, which was not statistically significant (CI = -6.2:10.8, P-value = 0.593). The mean FJS of the SBTKA patients was 59.9 (SD = 27.5), and the mean FJS of the UTKA patients was 57.5 (SD = 28.8).
  
  
  CONCLUSIONS
  SBTKA and UTKA patients exhibited similar joint functionality and knee awareness. Our results support the use of SBTKA in selected patients suffering from clinically symptomatic bilateral osteoarthritis.
authors.affiliation: Roshan Latifi, Morten Grove Thomsen, Thomas Kallemose, Henrik Husted, Anders Troelsen, Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, DK-2650 Hvidovre, Copenhagen, Denmark.
authors.forename: Roshan
authors.initials: R
authors.lastname: Latifi
authors.affiliation: Roshan Latifi, Morten Grove Thomsen, Thomas Kallemose, Henrik Husted, Anders Troelsen, Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, DK-2650 Hvidovre, Copenhagen, Denmark.
authors.forename: Morten Grove
authors.initials: MG
authors.lastname: Thomsen
authors.affiliation: Roshan Latifi, Morten Grove Thomsen, Thomas Kallemose, Henrik Husted, Anders Troelsen, Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, DK-2650 Hvidovre, Copenhagen, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kallemose
authors.affiliation: Roshan Latifi, Morten Grove Thomsen, Thomas Kallemose, Henrik Husted, Anders Troelsen, Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, DK-2650 Hvidovre, Copenhagen, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Husted
authors.affiliation: Roshan Latifi, Morten Grove Thomsen, Thomas Kallemose, Henrik Husted, Anders Troelsen, Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, DK-2650 Hvidovre, Copenhagen, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Troelsen
keywords: Forgotten Joint Score; Knee awareness; Patient-reported outcomes; Simultaneous bilateral total knee arthroplasty; Unilateral total knee arthroplasty