title: Prevalence of anterior knee pain among patients following total knee arthroplasty with nonreplaced patella: a retrospective study of 1778 knees.
abstract: OBJECTIVE
  Anterior knee pain (AKP) may compromise the results of total knee arthroplasty in more than quarter of cases. The aim of the current work was to determine the prevalence of AKP and the severity of patellofemoral symptoms among patients who received a total knee arthroplasty with non-replaced patella in East-Tallinn Central Hospital from January 1, 2000 to December 31, 2009.
  
  
  METHODS
  We carried out a retrospective study involving 1778 consecutive total knee arthroplasties with non-replaced patella. Mean follow-up time was 68 months. We collected data by two patient-reported measures: the knee pain questionnaire and the Kujala score.
  
  
  RESULTS
  We diagnosed AKP among 20.2% of patients, 33.6% had pain in the knee from a source other than patellofemoral joint and 46.2% were pain free. In 87.3% of AKP cases the pain emerged within the first five years of knee replacement. AKP was more prevalent among patients with osteoarthritis compared to rheumatoid arthritis and among patients below 60 years. There was no difference in the prevalence of AKP in terms of gender or mobile and fixed bearing implants. The severity of patellofemoral symptoms in case of AKP was moderate.
  
  
  CONCLUSIONS
  AKP is a frequent complication of total knee arthroplasty with non-replaced patella and patients undergoing this procedure should be apprised of the high probability of experiencing pain in the anterior part of the replaced knee.
authors.affiliation: East Tallinn Central Hospital, Department of Orthopaedic Surgery, Tallinn, Estonia; University of Tartu, Tartu, Estonia. Electronic address: vahur.metsna@itk.ee.
authors.forename: Vahur
authors.initials: V
authors.lastname: Metsna
authors.affiliation: National Institute for Health Development, Tallinn, Estonia.
authors.forename: Sigrid
authors.initials: S
authors.lastname: Vorobjov
authors.affiliation: University of Tartu, Tartu, Estonia; Tartu University Hospital, Department of Orthopaedic Surgery, Tartu, Estonia.
authors.forename: Aare
authors.initials: A
authors.lastname: Märtson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000601:surgery; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000601:surgery; D010149:Postoperative Pain / Q000453:epidemiology*; D010329:Patella / Q000601:surgery*; D057071:Patellofemoral Joint / Q000503:physiopathology* / Q000601:surgery*; D015995:Prevalence; D012189:Retrospective Studies; D011795:Surveys and Questionnaires
keywords: Arthroplasty; Knee; Pain; Patella; Prevalence