title: Prevalence of jumper's knee among elite athletes from different sports: a cross-sectional study.
abstract: BACKGROUND
  The prevalence of jumper's knee across different sports has not been examined, and it is not known if there is a gender difference. Data from surgical case series indicate that there may be a high prevalence in sports with high speed and power demands.
  
  
  OBJECTIVE
  The aim of this study was to estimate the prevalence of jumper's knee in different sports among female and male athletes and to correlate the prevalence to the loading characteristics of the extensor mechanism in these sports.
  
  
  METHODS
  Cross-sectional study; Level of evidence, 4.
  
  
  METHODS
  The authors examined approximately 50 Norwegian male and female athletes at the national elite level from each of the following 9 sports: athletics (male athletes: high jump, 100- and 200-m sprint), basketball (male athletes), ice hockey (male athletes), volleyball (male athletes), orienteering (male athletes), road cycling (male athletes), soccer (male and female athletes), team handball (male and female athletes), and wrestling (male athletes). The examination included an interview on individual characteristics (weight, age, height, and training background), a clinical examination, and self-recorded Victorian Institute of Sport Assessment score from 0 (worst) to 100 (best).
  
  
  RESULTS
  The overall prevalence of current jumper's knee was 14.2% (87 of 613 athletes), with a significant difference between sports with different performance characteristics (range, 0%-45%). In addition, 51 athletes (8%) reported previous symptoms. The prevalence of current symptoms was highest in volleyball (44.6%+/-6.6%) and basketball (31.9%+/-6.8%), whereas there were no cases in cycling or orienteering. The prevalence of current jumper's knee was lower among women (5.6%+/-2.2%) compared with men (13.5%+/-3.0%; chi2 test, P=.042). The duration of symptoms among athletes with current jumper's knee (n=87) was 32+/-25 (standard deviation) months, with a Victorian Institute of Sport Assessment score of 64+/-19.
  
  
  CONCLUSIONS
  The prevalence of jumper's knee is high in sports characterized by high demands on speed and power for the leg extensors. The symptoms are often serious, resulting in long-standing impairment of athletic performance.
authors.affiliation: Oslo Sport Trauma Research Center, Norwegian University of Sport and Physical Education, PO Box 4014, Ullevål Stadion, 0806 Oslo, Norway.
authors.forename: Oystein B
authors.initials: OB
authors.lastname: Lian
authors.forename: Lars
authors.initials: L
authors.lastname: Engebretsen
authors.forename: Roald
authors.initials: R
authors.lastname: Bahr
mesh_terms: D001265:Athletic Injuries / Q000453:epidemiology*; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000453:epidemiology*; D008297:Male; D012737:Sex Factors; D016474:Weight-Bearing