Pronation injuries of the ankle in children. Retrospective study of radiographical classification and treatment.

In a retrospective study in children aged 0-18 years, 457 ankle fractures in children were classified traumatologically according to Gerner-Smidt or Lauge-Hansen. Anatomically, ankle fractures with open growth plates were classified according to the Salter-Harris classification. Pronation injuries constituted 18% of the ankle injuries and showed different fracture patterns. In total 83 pronation injuries were found. Of these, 52 showed open growth plates: 25 pronation-abduction, 23 pronation-eversion, and 4 pronation-dorsal flexion injuries. The pronation-abduction injuries were classified into two groups. In 15, a detachment of the deltoid ligament at the medial malleolus, visible on radiographs as a minimal fragment or transverse fracture of the medial malleolus, was found; seven showed in addition a fracture through the growth plate (Salter-Harris type I or II) or a metaphyseal fracture of the distal fibula. In 10, a physeal fracture through the distal tibia (Salter-Harris type I) was found. Of these, seven had in addition a metaphyseal fibular fracture. Pronation-eversion injuries showed in 21 cases a physeal-metaphyseal fracture (Salter-Harris type II) with an antero-lateral metaphyseal fragment (Stage I-II); 17 had in addition a metaphyseal fibular fracture (Stage III). A minimal posterolateral metaphyseal fragment of the distal tibia represents the fourth stage but could not adequately be separated from the third, so Stages III and IV were combined. Pronation-dorsal flexion showed a physeal-metaphyseal fracture in four cases with an anteriorly situated metaphyseal fragment (Stages I-II); one case also had a metaphyseal fracture of the distal fibula (Stage III). Pronation-eversion injuries showed frequently displacement and were more commonly treated by reduction than pronation-abduction and supination injuries including supination-eversion injuries of intra-articular type. However, complete reduction of pronation-eversion injuries with closed methods often proved difficult.