title: Catcher's Knee: Posterior Femoral Condyle Juvenile Osteochondritis Dissecans in Children and Adolescents.
abstract: BACKGROUND
  Juvenile osteochondritis dissecans is an idiopathic condition involving subchondral bone and articular cartilage in skeletally immature patients in whom the growth plates are open, potentially leading to lesion instability. Because of the differing forces experienced by baseball/softball catchers versus position players, the age at which lesions develop and the characteristics of the lesions themselves may differ between these 2 populations. The purpose of the study was to examine relative age and characteristics of osteochondritis dissecans (OCD) knee lesions in catchers compared with position players.
  
  
  METHODS
  Using a text-based search tool that queries clinic notes and operative reports, computerized medical records from 1990 to 2014 from the Sports Medicine Program of a tertiary care Children's Hospital were searched to find children and adolescents who had OCD of the knee, played baseball/softball, had a specified field position, and had magnetic resonance imaging of the knee. Ultimately, 98 knees (78 patients) were identified: 33 knees (29 patients) in catchers and 65 knees (49 patients) in noncatchers. Data collected included position played (catcher/noncatcher), demographics (age, unilateral/bilateral, and sex), lesion severity, and sagittal and coronal lesion location.
  
  
  RESULTS
  When compared with noncatchers, catchers presented at a younger age (P=0.035) but were similar with respect to bilateral involvement (P=0.115), sex (P=0.457), and lesion severity (P=0.484). Lesions in catchers were more posterior on the femoral condyle in the sagittal plane (P=0.004) but similar in location in the coronal plane (P=0.210).
  
  
  CONCLUSIONS
  Catchers developed OCD at a younger age and in a more posterior location on the medial and lateral femoral condyles than noncatchers. These results may represent the effects of repetitive and persistent loading of the knees in the hyperflexed position required of catchers. Increased awareness of this risk may lead to surveillance and prevention programs.
  
  
  METHODS
  Level III-case-control study.
authors.affiliation: Harvard Medical School.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: McElroy
authors.affiliation: Department of Orthopaedic Surgery, Boston Children's Hospital, Boston, MA.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Riley
authors.affiliation: Department of Orthopaedic Surgery, Boston Children's Hospital, Boston, MA.
authors.forename: Frances A
authors.initials: FA
authors.lastname: Tepolt
authors.affiliation: Department of Orthopaedic Surgery, Boston Children's Hospital, Boston, MA.
authors.forename: Adam Y
authors.initials: AY
authors.lastname: Nasreddine
authors.affiliation: Harvard Medical School.|Department of Orthopaedic Surgery, Boston Children's Hospital, Boston, MA.
authors.forename: Mininder S
authors.initials: MS
authors.lastname: Kocher
mesh_terms: D000293:Adolescent; D001484:Baseball / Q000293:injuries*; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000293:injuries; D016022:Case-Control Studies; D002648:Child; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging*; D006132:Growth Plate / Q000000981:diagnostic imaging; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010008:Osteochondritis Dissecans / Q000000981:diagnostic imaging* / Q000209:etiology