Objective To investigate the surgical techniques and the cl inical outcomes of treating severe pronationexternal rotation ankle fractures combined with deltoid l igament injuries. Methods Between July 2005 and April 2007, 17 patients with grade-IV pronation-external rotation ankle fractures combined with deltoid l igament injuries were treated by open reduction and internal fixation with l igament repair by using suture anchors. There were 13 males and 4 femaleswith an average age of 36.5 years (21-56 years). All cases were closed injuries with l imitation of motion after initial physical examination. The X-ray and CT showed that all patients were characterized with lateral and posterior malleolus fractures and significant lateral shift of talus, but without medial malleous fracture before operation. All fractures were classified into grade-IV pronation- external rotation or type C according to Lauge-Hansen criterion and Danis-Weber standard respectively. The disease course was from 4 days to 7 days with an average of 5.6 days. Results All incisions healed by first intention Seventeen patients were followed up 11-24 months (mean 15.6 months). The X-ray films showed that all patients achieved bony heal ing. The heal ing time was 11-16 weeks (mean 14.8 weeks). According to the Baird-Jackson’s scoring system, the results were excellent in 5 cases, good in 9 cases, fair in 2 cases and poor in 1 case, the excellent and good rate was 82.4%. No operation compl ication occurred. Medial clear space was significantly decreased postoperatively compared with that before operation [(3.16 ± 0.37) mm vs. (4.87 ± 0.43) mm] (P lt; 0.01). In gravity stress radiographs, there was no significant difference in medial clear space between collateral ankle and injured ankle after operation [(3.47 ± 0.43) mm vs. (3.55 ± 0.44) mm] (P gt; 0.05). Conclusion It is emphasized that full attention should be given to reconstruction of medial l igament structures as well as open reduction and internal fixation in treating grade-IV pronation-external rotation ankle fractures combined with deltoid l igament injuries.