title: The anterior tilt angle of the proximal tibia epiphyseal plate: a significant radiological finding in young children with trampoline fractures.
abstract: OBJECTIVE
  Evaluation of the anterior tilt angle of the proximal tibia epiphyseal plate in young children, which suffered a trampoline fracture in comparison with a normal population.
  
  
  METHODS
  62 children (31 females, 31 males) between 2 and 5 years of age (average 2 years 11 months, standard deviation 11 months) with radiographs in two views of the tibia were included in this retrospective study. 25 children with proximal tibia fractures were injured with a history of jumping on a trampoline. All other causes for tibia fractures were excluded. A normal age-mapped control cohort of 37 children was compared. These children had neither evidence of a trampoline related injury nor a fracture of the tibia. The anterior tilt angle of the epiphyseal plate of the tibia was defined as an angle between the proximal tibia physis and the distal tibia physis on a lateral view. Two radiologists evaluated all radiographs for fractures and measured the anterior tilt angle in consensus. An unpaired Student's t-test was used for statistical analysis (SPSS). Original reports were reviewed and compared with the radiological findings and follow-up radiographs.
  
  
  RESULTS
  In the normal control group, the average anterior tilt angle measured -3.2°, SD ± 2.8°. The children with trampoline fractures showed an anterior tilt of +4.4°, SD ± 2.9°. The difference was statistically significant, P<0.0001. In 6 patients (24% of all patients with confirmed fractures) the original report missed to diagnose the proximal tibial fracture.
  
  
  CONCLUSIONS
  Young children between 2 and 5 years of age are at risk for proximal tibia fractures while jumping on a trampoline. These fractures may be very subtle and difficult to detect on initial radiographs. Measurement of the anterior tilt angle of the proximal tibia epiphyseal plate on lateral radiographs is supportive for interpreting correctly trampoline fractures.
authors.affiliation: University Hospital Bern, Inselspital, Department of Diagnostic, Interventional and Pediatric Radiology, CH-3010 Bern, Switzerland. Electronic address: enno.stranzinger@insel.ch.
authors.forename: Enno
authors.initials: E
authors.lastname: Stranzinger
authors.affiliation: University Hospital Bern, Inselspital, Department of Diagnostic, Interventional and Pediatric Radiology, CH-3010 Bern, Switzerland. Electronic address: lars.leidolt@insel.ch.
authors.forename: Lars
authors.initials: L
authors.lastname: Leidolt
authors.affiliation: Cantonal Hospital Aarau, Pediatric Radiology, Tellstrasse, CH-5001 Aarau, Switzerland. Electronic address: georg.eich@ksa.ch.
authors.forename: Georg
authors.initials: G
authors.lastname: Eich
authors.affiliation: Cantonal Hospital Aarau, Pediatric Surgery, Tellstrasse, CH-5001 Aarau, Switzerland. Electronic address: peter.klimek@ksa.ch.
authors.forename: Peter Michael
authors.initials: PM
authors.lastname: Klimek
mesh_terms: D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010988:Play and Playthings / Q000293:injuries*; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D000072042:Salter-Harris Fractures; D013978:Tibial Fractures / Q000000981:diagnostic imaging* / Q000209:etiology*
keywords: Anterior tilt; Children; Trampoline fracture; X-ray