title: Standardization of patellofemoral morphology in the pediatric knee.
abstract: BACKGROUND
  Our understanding of osseous morphology and pathology of the patellofemoral joint continues to improve with the use of magnetic resonance imaging (MRI), but a paucity of data currently exists in the pediatric population.
  
  
  OBJECTIVE
  We aim to formulate a reproducible means of quantitative assessment of patellofemoral morphology in children using MRI and to describe morphological changes based on sex and age.
  
  
  METHODS
  We identified 414 children presenting between 2002 and 2014 who obtained a knee MRI to evaluate for knee pain or clinically suspected knee pathology. After application of inclusion criteria, 144 "normal" MRIs in 131 children (71 boys, 60 girls) were included in the analysis. The following MRI measurements were recorded: lateral trochlear inclination, trochlear facet asymmetry, trochlear depth, tibial tuberosity-trochlear groove distance, sulcus angle and patellar height ratio. To assess intraobserver reliability, measurements in 30 randomly selected children were repeated. Differences between patient age and sex were assessed using independent t-tests and adjusted regression analysis.
  
  
  RESULTS
  All recorded measurements had strong to very strong inter- and intraobserver reliability: lateral trochlear inclination (0.91/0.82), trochlear facet asymmetry (0.81/0.83), trochlear depth (0.83/0.90), tibial tuberosity-trochlear groove distance (0.97/0.87), sulcus angle (0.84/0.78) and patellar height ratio (0.96/0.83). When age and sex were mutually adjusted, statistically significant differences between males and females were observed in trochlear depth (P = 0.0084) and patellar height ratio (P = 0.0035). However, statistically significant age differences were found on all measurements except for lateral trochlear inclination. As expected, mean measurement values approached adult norms throughout skeletal maturation suggestive of age-dependent patellofemoral maturation.
  
  
  CONCLUSIONS
  Our data verify the development of patellofemoral morphology with advancing age. We found that six of the most commonly used patellofemoral measurements in adults can be accurately reproduced regardless of age.
authors.affiliation: Department of Orthopedic Surgery, Nationwide Children's Hospital, 700 Children's Drive Suite A2630, Columbus, OH, 43205-2696, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Mundy
authors.affiliation: Department of Orthopaedics, The Ohio State University, Columbus, OH, USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Ravindra
authors.affiliation: Department of Orthopedic Surgery, Nationwide Children's Hospital, 700 Children's Drive Suite A2630, Columbus, OH, 43205-2696, USA.
authors.forename: Jingzhen
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Radiology, Nationwide Children's Hospital, Columbus, OH, USA.
authors.forename: Brent H
authors.initials: BH
authors.lastname: Adler
authors.affiliation: Department of Orthopedic Surgery, Nationwide Children's Hospital, 700 Children's Drive Suite A2630, Columbus, OH, 43205-2696, USA. kevin.klingele@nationwidechildrens.org.|Department of Orthopaedics, The Ohio State University, Columbus, OH, USA. kevin.klingele@nationwidechildrens.org.
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Klingele
mesh_terms: D000293:Adolescent; D000375:Aging / Q000473:pathology*; D059925:Anatomic Landmarks / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging / Q000592:standards*; D008297:Male; D015588:Observer Variation; D057071:Patellofemoral Joint / Q000473:pathology*; D017410:Practice Guidelines as Topic; D011871:Radiology / Q000592:standards*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Children; Knee; Magnetic resonance imaging; Morphology; Patella; Patellofemoral joint