To evaluate the factors influencing periosteal interposition in distal tibial physeal fractures of children.

34 cases of distal tibial physeal fractures were analysed. We confirmed the presence of periosteal interposition with MRI in all cases and accessed the relationship between periosteal interposition and gender, age, cause of injury, type of fracture, degree of initial displacement and after closed reduction.

9 (26.5%) of 34 fractures had interposed periosteum. There was no statistically significant correlation between periosteal interposition and gender, age, cause of injury (p>0.05). 5 (83.3%) of 6 pronation-eversion-external rotation type of fractures according to Dias-Tachjian classification had interposed periosteum and that was a statistically significant correlation (p=0.006). As Salter-Harris type was toward to high degree, there were decreasing tendency of periosteal interposition (p=0.026). There was high rate of periosteal interposition in case of displacement more than 2 mm in each initial and after closed reduction (p<0.05).

There was high incidence of periosteal interposition in pronation-eversion-external rotation type with displacement more than 2 mm in distal tibial physeal fractures of children. But, periosteal interposition could occur in fractures with mild displacement less than 2 mm, if initial fracture displacement was more than 2 mm, the methods of treatment should be decided after confirm the presence of periosteal interposition with MRI after closed reduction.