We have investigated total 294 cases of ankle fractures, which were treated and followed for average 17 months after treatment at St. Marys hospital since 1980, to detect the complications and to define their provoking factors. The results were as follows;

1. Twenty-six cases out of total 294 cases of ankle fracture(8.8%) were complicated clinically and radiologically.

2. Their complications are osteoarthritis(8/26, 31%), diastasis of distal tibio-fibular syndesmosis(9/26, 34.6%), varus ankle deformity(5/26, 19.2%), malunion(6/26, 23%), non-union and ankle instability(each 2/26, 7.7%) in its order, but 14 cases of the 26 cases complained painful limited ankle motion and limp. So, clinical symptoms are not closely related with radiologic changes in complications of ankle fracture.

3. The complications are common in elderly patients over 50 of their ages(12.26, 46%) and in younger patients under 16 of their ages(5/26, 20%).

4. The complications are frequently found in pronation-external rotation injuries(6/61, 1O%), pronation-dorsiflexion(9/14, 64%) and supination-external rotation injuries(8/165, 4.8%) in orders.

5. Malpractice with misuse of instrument(12/26, 46%), mistakes in preoperative evaluation and neglect any ankle fracture or diastasis of syndesmosis(8/26, 30.7%) and severity of injuries(6.26, 23%) are common causes of complications of ankle fractures.

6. Varus ankle deformity due to early epiphyseal closure are shown in 5 cases(5/28, 20%) and three of them are treated with supramalleolar corrective osteotomies and Langenskiolds physolysis

In conclusion, the complications of ankle fracture could be reduced by accurate pre-operative evaluation to detect the hidden soft tissue injuries or fracture mechanism and by also anatomic reduction, rigid internal fixation and early ankle motions. childrens ankle fracture will induce angular deformity and limb length discrepancy due to frequent epjphyseal damage, so long-term follow up should be kept in mind until their skeletal growth are ceased.