Treatment of proximal tibial varus malunion with a unilateral external fixator

Objective To review gradual correction of proximal tibial varus malunion with a unilateral external fixator for osteogenetic distraction. Methods From July 2004 to August 2010, we treated 5 cases of proximal tibial varus malunion with a unilateral external fixator. They were 2 men and 3 women,with an average age of 32 years (from 18 to 42 years). Two cases were malunion after tibial plateau fracture,2 after proximal tibial fracture, and one after osteogenetic distraction. After fibular osteotomy, a tibial unilateral external fixator was installed before proximal tibial osteotomy. Varus was corrected for 7 to 10 days after surgery by gradual distraction till the same alignment was obtained as the contralateral side. The external fixator was not removed until consolidation and full weight bearing. Results The follow-ups ranged from 5 to 11 months (average, 8. 4 months). Four cases got united after 3 to 6 months (average, 4. 8 months).Time for external fixator ranged from 4 to 8 months (average, 6. 8 months) . One case obtained bone union after bone grafting. All fibulas healed after osteotomy. No other complications were present except mild pin-tract problems. Compared with the contralateral side, the corrected malalignment deviation was laterally displaced by 8 mm on average (from 1 to 13 mm), the corrected medial proximal tibial angle was 90° on average (from 87° to 92°), the limb length discrepancy was -6 to 1 mm, and the tibial length discrepancy was - 2 to 3 mm. Conclusions Proximal tibial varus malunion can be corrected gradually and effectively by a unilateral external fixator. Its advantages over valgus osteotomy and internal fixation are less invasion due to simple transverse osteotomy, accurate correction not only of angulation but also of length discrepancy, and no need of bone grafting or implant removal. Key words: Tibial fractures;  Osteotomy;  Bone grafting;  External fixators