Prevalence of Jumper's knee among nonelite athletes from different sports: a cross-sectional survey.

BACKGROUND The prevalence of jumper's knee among nonelite athletes from different sports is unknown. PURPOSE This study was undertaken to determine the prevalence of jumper's knee in nonelite athletes from different sports and to determine potential risk factors for jumper's knee. DESIGN Cohort study (prevalence); Level of evidence, 2. METHODS The authors interviewed 891 male and female nonelite athletes from 7 popular sports in The Netherlands: basketball, volleyball, handball, korfball, soccer, field hockey, and track and field. Using a specially developed questionnaire, information was obtained about individual characteristics (age, height, and weight), training background, previous and actual knee problems, and the VISA-P (Victorian Institute of Sport Assessment-Patella) score. RESULTS The overall prevalence of current jumper's knee was 8.5% (78 of 891 athletes), showing a significant difference between sports with different loading characteristics. Prevalence was highest among volleyball players (14.4%) and lowest among soccer players (2.5%); it was significantly higher among male athletes (51 of 502 [10.2%]) than female athletes (25 of 389 [6.4%]) (χ(2) = 3.91, P = .048). The mean duration of symptoms was 18.9 months (standard deviation [SD], 21.6; median value, 12.0; range, 2.0-59.8). The mean VISA-P score of the athletes with jumper's knee was 71.4 (SD, 13.8). Athletes with jumper's knee were significantly younger, taller, and heavier than those without jumper's knee. CONCLUSION Prevalence of jumper's knee is high among nonelite athletes and varies between 14.4% and 2.5% for different sports. Jumper's knee is almost twice as common among male nonelite athletes compared with female athletes. Different sport-specific loading characteristics of the knee extensor apparatus, a younger age, a taller body stature, and higher body weight seem to be risk factors associated with patellar tendinopathy.