title: The demographics and epidemiology of osteochondritis dissecans of the knee in children and adolescents.
abstract: BACKGROUND
  Osteochondritis dissecans (OCD) is a disorder of subchondral bone and articular cartilage whose incidence in children is not clearly known.
  
  
  OBJECTIVE
  The purpose of this study was to assess the demographics and epidemiology of OCD of the knee in children.
  
  
  METHODS
  Descriptive epidemiology study.
  
  
  METHODS
  A retrospective chart review of an integrated health system was performed on patients with OCD of the knee aged 2 to 19 years from 2007 to 2011, with over 1 million patients in this cohort. Lesion location, laterality, and all patient demographics were recorded. The incidence of OCD was determined for the group as a whole and by sex and age group (2-5 years, 6-11 years, and 12-19 years). Patient differences based on age, sex, and ethnicity were analyzed, and using multivariable logistic regression models, associations between age, sex, ethnicity, and diagnosis of OCD of the knee were evaluated.
  
  
  RESULTS
  One hundred ninety-two patients with 206 OCD lesions of the knee fit the inclusion criteria. No OCD lesion of the knee was found in 2- to 5-year-old children. One hundred thirty-one (63.6%) lesions were in the medial femoral condyle, 67 (32.5%) were in the lateral femoral condyle, 96 (50.0%) lesions were right sided, 82 (42.7%) were left sided, and 14 (7.3%) were bilateral. The incidence of patients with OCD of the knee aged 6 to 19 years was 9.5 per 100,000 overall and 15.4 and 3.3 per 100,000 for male and female patients, respectively. Those aged 12 to 19 years represented the vast majority of OCD, with an incidence of 11.2 per 100,000 versus 6.8 per 100,000 for those aged 6 to 11 years. For those aged 6 to 11 and 12 to 19 years, female patients had an incidence of 2.3 and 3.9 per 100,000, respectively, while male patients had an incidence of 11.1 and 18.1 per 100,000, respectively. Multivariable logistic regression analysis revealed a 3.3-fold increased risk of OCD of the knee in patients aged 12 to 19 years compared with those aged 6 to 11 years (P < .001; 95% confidence interval [CI], 2.37-4.48), and male patients had 3.8 times a greater risk of OCD of the knee than female patients (P < .001; 95% CI, 2.71-5.41). Based on race and ethnicity, blacks had the highest odds ratio of OCD of the knee compared with all other ethnic groups.
  
  
  CONCLUSIONS
  In this population-based cohort study of pediatric OCD of the knee, male patients had a much greater incidence of OCD and almost 4 times the risk of OCD compared with female patients. Also, patients aged 12 to 19 years had 3 times the risk of OCD of the knee as compared with 6- to 11-year-old children.
authors.affiliation: Jeffrey I. Kessler, Kaiser Permanente Southern California, 4760 Sunset Boulevard, Los Angeles, CA 90027. Jeffrey.I.Kessler@kp.org.
authors.forename: Jeffrey I
authors.initials: JI
authors.lastname: Kessler
authors.forename: Hooman
authors.initials: H
authors.lastname: Nikizad
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Shea
authors.forename: John C
authors.initials: JC
authors.lastname: Jacobs
authors.forename: Judith D
authors.initials: JD
authors.lastname: Bebchuk
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Weiss
mesh_terms: D000293:Adolescent; D002140:California / Q000453:epidemiology; D002358:Cartilage, Articular; D002648:Child; D002675:Child, Preschool; D003710:Demography; D005260:Female; D006801:Humans; D015994:Incidence; D007719:Knee Joint; D008297:Male; D010008:Osteochondritis Dissecans / Q000453:epidemiology* / Q000208:ethnology; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D055815:Young Adult
keywords: OCD; child; epidemiology; incidence; knee; osteochondritis dissecans; pediatric