Ankle joint is important as a weight-bearing joint and ankle diastasis requires accurate diagnosis and treatment.

The authors analysed 82 cases of ankle diastasis with fibular fracture during the year 1986 through 1992 at YoungDong Severance Hospital.

The results obtained are as follows.

1. The most common cause of injury was slip down, and traffic accident and fall down in order.

2. By Weber classification, 42 cases were type BS(+) and 40 cases were type C. By Lauge-Hansen classification, supination-external rotation was most common (35 cases).

3. Open reduction was done in all cases for fracture of fibula. 45 cases of ankle diastasis were treated with one transfixation screw and 37 cases without transfixation after confirmation by Cotton test.

4. The result according to Cottons criteria, 39 cases(86.7%) were were good or fair in transfixation group, and 34 cases(91.9%) in nontransfixation group. In conclusion, the transfixation screw was not necessary in cases of ankle diastasis which was considered as stable by Cotton test after internal fixation for the fracture of fibula.