Objective To analyse the cl inical outcomes of the Z-osteotomy of the distal fibula to correct widened mortice of the ankle after fracture. Methods Between September 2009 and February 2011, 5 patients (5 feet) with widened ankle mortice after fracture underwent Z-osteotomy. There were 4 males and 1 female, aged from 23 to 58 years (mean, 38 years). At 3 months after operation of internal fixation when function exercises were done, patients got pains. The interval between trauma and operation ranged from 5 to 36 months (mean, 13.2 months). Lateral pressure test showed positive in2 cases and negative in 3 cases. American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score was 50.2 ±17.3. Results Primary healing of incision was achieved in all cases. Five patients were followed up 9 to 24 months (mean, 15.6 months). Mild to moderate swelling of the affected limb and anterolateral skin numbness of the i psilateral dorsal foot occurred, and gradually improved. The cl inical exam and radiology showed bone union at 12-15 weeks (mean, 13.5 weeks). Postoperative range of motion of ankle had no significant improvement. AOFAS ankle-hindfoot scores were 76.8 ± 11.2 at 6 months after operation, and 85.4 ± 3.2 at last follow-up, showing significant differences when compared with preoperative score (P lt; 0.05). Conclusion Shortened fibula is the main cause of widened ankle mortice after fracture; Z-osteotomy can effectively reduce the width of the ankle mortice, increase the stabil ity of ankle joint, and decrease the complication rate.