title: Grey-scale ultrasound findings of lower extremity entheses in healthy children.
abstract: BACKGROUND
  To describe grey-scale sonographic findings in lower extremity entheses in healthy children.
  
  
  METHODS
  Healthy patients referred to Orthopedic Surgery or Adolescent Medicine outpatient clinics or their siblings ages 5-18 years were recruited. Grey-scale ultrasound was performed on 3 entheseal sites bilaterally, the proximal patellar ligament insertion (PPL), distal patellar ligament insertion (DPL), and Achilles tendon insertion (AT). Entheseal thickness and quality were recorded. Comparison of thickness between contralateral sites was evaluated to determine within subject site variability.
  
  
  RESULTS
  702 entheses were examined in 117 children. Age had a weak positive correlation with thickness with large variability. Weight had the strongest correlation to thickness. Contralateral sites are comparable in thickness; a difference of 28%, 26%, and 18% between bilateral PPL, DPL, and AT, respectively, falls within the 95th percentile of the healthy pediatric population in this study. The patellar ligament contour evolved with age from a curved to linear contour.
  
  
  CONCLUSIONS
  Weight is the best predictor of entheseal thickness in children although there is a large degree of variability. Contralateral entheses are comparable in thickness. A difference below 28%, 26%, and 18% between bilateral PPL, DPL, and AT, respectively, falls within the 95(th) percentile.
authors.affiliation: Children's Hospital Colorado Pediatric Rheumatology, 13123 East 16th Street, Box B311, Aurora, CO, 80045, USA. clara.lin@childrenscolorado.org.
authors.forename: Clara
authors.initials: C
authors.lastname: Lin
authors.affiliation: University of California-San Francisco Pediatric Orthopedic Surgery, 400 Parnassus Ave, San Francisco, CA, 94143, USA. diab@orthosurg.ucsf.edu.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Diab
authors.affiliation: Floating Hospital for Children @ Tufts Medical Center, 800 Washington Street #190, Boston, MA, 02111, USA. DMilojevic@tuftsmedicalcenter.org.
authors.forename: Diana
authors.initials: D
authors.lastname: Milojevic
mesh_terms: D000125:Achilles Tendon / Q000000981:diagnostic imaging*; D000293:Adolescent; D000367:Age Factors; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D003238:Connective Tissue / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D017847:Patellar Ligament / Q000000981:diagnostic imaging*; D010865:Pilot Projects; D014463:Ultrasonography / Q000379:methods*