title: The 6-year trajectory of non-traumatic knee symptoms (including patellofemoral pain) in adolescents and young adults in general practice: a study of clinical predictors.
abstract: OBJECTIVE
  (1) To assess the 1-year and 6-year courses of non-traumatic knee symptoms in adolescents and young adults presenting in general practice. (2) To identify prognostic factors for persistent knee symptoms at 1-year follow-up.
  
  
  METHODS
  Adolescents and young adults (12-35 years; n=172) with non-traumatic knee symptoms were included in the cohort study by their general practitioner (GP) and followed for 6 years. Multivariable logistic regression analysis was used to identify prognostic factors for persistent knee symptoms at 1-year follow-up and the area under the receiver operating curve (AUC) was calculated.
  
  
  RESULTS
  Persistent knee symptoms in patients receiving a GP diagnosis of unspecified knee symptoms were reported by 41% of the patients at 1-year follow-up and by 19% of the available patients at 6-year follow-up. Patients receiving a GP diagnosis of patellofemoral pain syndrome had the worse prognosis, with 40% reporting persistent knee symptoms at 6-year follow-up. Prognostic factors associated with persistent knee symptoms at 1-year follow-up were BMI >25, low/middle education level, bilateral symptoms and self-reported absence of crepitus of the knee (AUC 0.80) for patients receiving a GP diagnosis of unspecified knee symptoms. For patients receiving a GP diagnosis of patellofemoral pain syndrome, prognostic factors were low/middle education level, poor health, having bilateral symptoms and self-report of a swollen knee (AUC 0.76).
  
  
  CONCLUSIONS
  The prognosis of non-traumatic knee symptoms in adolescents and young adults in general practice is not as good as was previously assumed. Several prognostic factors collected at baseline were associated with persistent knee symptoms at follow-up. However, the results should be replicated in another larger study.
authors.affiliation: Department of General Practice, Erasmus MC University Medical Center, Rotterdam, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Kastelein
authors.affiliation: Department of General Practice, Erasmus MC University Medical Center, Rotterdam, The Netherlands.
authors.forename: P A J
authors.initials: PA
authors.lastname: Luijsterburg
authors.affiliation: Department of General Practice, Erasmus MC University Medical Center, Rotterdam, The Netherlands.
authors.forename: E M
authors.initials: EM
authors.lastname: Heintjes
authors.affiliation: Department of General Practice, Erasmus MC University Medical Center, Rotterdam, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: van Middelkoop
authors.affiliation: Department of Orthopaedics, Erasmus MC University Medical Center, Rotterdam, The Netherlands.
authors.forename: J A N
authors.initials: JA
authors.lastname: Verhaar
authors.affiliation: Department of General Practice, Erasmus MC University Medical Center, Rotterdam, The Netherlands.
authors.forename: B W
authors.initials: BW
authors.lastname: Koes
authors.affiliation: Department of General Practice, Erasmus MC University Medical Center, Rotterdam, The Netherlands Department of Orthopaedics, Erasmus MC University Medical Center, Rotterdam, The Netherlands.
authors.forename: S M A
authors.initials: SM
authors.lastname: Bierma-Zeinstra
mesh_terms: D000293:Adolescent; D019540:Area Under Curve; D002648:Child; D059350:Chronic Pain / Q000453:epidemiology; D004522:Educational Status; D005260:Female; D058006:General Practice / Q000706:statistics & numerical data; D006801:Humans; D007592:Joint Diseases / Q000453:epidemiology*; D007719:Knee Joint; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D046788:Patellofemoral Pain Syndrome / Q000453:epidemiology; D011379:Prognosis; D011446:Prospective Studies; D057566:Self Report; D055815:Young Adult
keywords: Knee