title: "Forgotten knee" after total knee replacement: A pragmatic study from a single-centre cohort.
abstract: OBJECTIVE
  After total knee replacement (TKR), some patients find their operated knee totally natural and can be said to have "forgotten" it, while others, although satisfied with their results, remain conscious of their prosthesis. This is not well assessed on conventional end-points. Since 2001, we have studied the prevalence of "forgotten knee" (FK) after TKR in a prospective pragmatic cohort, with comparison to conventional scores.
  
  
  METHODS
  Patients undergoing TKR were enrolled between January 2001 and January 2008. Preoperative medical history and anthropometric and clinical data were recorded, and composite scores (Knee Society Score (KSS), Lequesne) were assessed. At each follow-up visit, FK acquisition was assessed by the closed question "Do you feel the operated knee to be always normal in all everyday activities?".
  
  
  RESULTS
  Five hundred and eighty-four TKRs in 485 patients were included. Among the TKR, 91.6% were performed for severe osteoarthritis of the knee. FK frequency at a mean 75.8 months' follow-up was 42.9% while 86.1% of TKRs had excellent (KS Knee Score (KSKS)>80) or 34.9% perfect (KSKS=100) outcome. Only 66.1% of the 204 TKRs with perfect outcome on KSKS were reported as FK. Most patients achieved FK within 18 months.
  
  
  CONCLUSIONS
  In this prospective study, 42.9% of TKRs were considered always forgotten in all everyday activities.
authors.affiliation: Department of Rheumatology, Henri-Mondor Hospital, AP-HP, 51, avenue du Maréchal-de-Lattre-de-Tassigny, 94010 Créteil cedex, France. Electronic address: florent.eymard@hmn.aphp.fr.
authors.forename: Florent
authors.initials: F
authors.lastname: Eymard
authors.affiliation: Department of Clinical Research, Henri-Mondor Hospital, AP-HP, 94010 Créteil cedex, France.
authors.forename: Anais
authors.initials: A
authors.lastname: Charles-Nelson
authors.affiliation: Department of Clinical Research, Henri-Mondor Hospital, AP-HP, 94010 Créteil cedex, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Katsahian
authors.affiliation: Department of Rheumatology, Henri-Mondor Hospital, AP-HP, 51, avenue du Maréchal-de-Lattre-de-Tassigny, 94010 Créteil cedex, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Chevalier
authors.affiliation: Department of Orthopaedic Surgery, Espace Médical Vauban, 75007 Paris, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Bercovy
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000523:psychology*; D001364:Awareness; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D011446:Prospective Studies; D016896:Treatment Outcome
keywords: Follow-up studies; Forgotten joint; Patient outcome assessment; Patient satisfaction; Total knee replacement