title: Precise risk factors for Osgood-Schlatter disease.
abstract: BACKGROUND
  A number of studies have examined the risk factors for Osgood-Schlatter disease (OSD). Studies on risk factors have not necessarily accurately demonstrated the risk factors of this disease because they were not prospective cohort studies or the populations in the studies were not categorized by the skeletal maturation of the tibial tuberosity. We can identify the precise risk factors for OSD by performing a prospective cohort study of a group of asymptomatic patients in particular times of adolescent using ultrasonography. In the present study, we aimed to investigate the precise risk factors for OSD.
  
  
  METHODS
  For all examinations, we used a 3-stage classification for tibial tuberosity development observed on ultrasonography: sonolucent (stage S), individual (stage I), and connective stages (stage C). Among 150 players with 300 knees, we included 37 male players with 70 knees at asymptomatic stage I on the first examination. We re-examined the included knees 1 year after the first examination and compared 10 knees with OSD (OSD group) and 60 knees without OSD (control group). Height, body weight, body mass index, tightness of the quadriceps femoris and hamstring muscles, muscle strength during knee extension, and flexion were assessed during the first medical examination.
  
  
  RESULTS
  The incidence of OSD was 14.3 % in this 1-year cohort study. A significant difference was found in body weight, quadriceps muscle tightness, and muscle tightness and strength during knee extension between the 2 groups. The precise risk factors for OSD were increased, namely the quadriceps femoris muscle tightness and strength during knee extension and flexibility of the hamstring muscles, using logistic regression analysis.
  
  
  CONCLUSIONS
  This information may be useful for teaching quadriceps stretching in preadolescent male football players with stage I.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Kanazawa University, 13-1 Takaramachi, Kanazawa, 920-0934, Japan, nakase1007@yahoo.co.jp.
authors.forename: Junsuke
authors.initials: J
authors.lastname: Nakase
authors.forename: Kenichi
authors.initials: K
authors.lastname: Goshima
authors.forename: Hitoaki
authors.initials: H
authors.lastname: Numata
authors.forename: Takeshi
authors.initials: T
authors.lastname: Oshima
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Takata
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsuchiya
mesh_terms: D000293:Adolescent; D001827:Body Height / Q000502:physiology; D016022:Case-Control Studies; D002648:Child; D015331:Cohort Studies; D006801:Humans; D016015:Logistic Models; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D055034:Osteochondrosis / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000503:physiopathology; D012307:Risk Factors; D013977:Tibia / Q000000981:diagnostic imaging / Q000254:growth & development; D014463:Ultrasonography