Different types of fixation for posterior pilon fractures

Abstract

Objective To explore the mechanisms of posterior pilon fractures and evaluate the curative effects of different types of fixation on the treatment of posterior pilon fractures. Methods We included in this retrospective study 20 patients with posterior pilon fracture who had been treated from January 2012 to January 2015 at our department. They were 10 men and 10 women, from 23 to 77 years of age (average, 50.6 years). According to the classification by Yu Guangrong, 5 cases belonged to type I, 3 to type Ⅱa, 4 to type Ⅱb, and 7 to type Ⅲ. One was not indentified because of lacking CT examination. The mechanisms included ground level fall in 2 cases, motor vehicle accident in 7, fall off stairs in 5, sport injury in 2, fall from a bike in one and fall from a height in 3. More than 25% of the articular surface was involved in 13 patients. Syndesmosis injury was identified in 6 patients by Cotton test during operation. Internal fixation varied accordingly. We recorded the mechanism, classification, proportion of the articular surface involved (more or less than 25%), and syndesmosis injury to figure out the characteristics of posterior pilon fractures. We used the Burwell-Charnley radiographic criteria to assess the postoperative reduction of the articular surface, and the Olerud-Molander scoring scale and visual analogue scale (VAS) to assess the ankle function. The curative effects of different types of fixation on the treatment of posterior pilon fractures were compared. Results Of the 20 patients, 17 were available for follow-up for 6 to 36 months (average, 17.8 months). Two patients received reoperation because of implant failure after cannulated screw fixation from anterior to posterior. The Burwell-Charnley radiographic evaluation revealed 12 anatoinical reducations and 8 fair reductions. The mean Olerud-Molander score for the 17 patients at the final follow-ups was 81.5 (range, from 35 to 100) and the mean walking VAS was 1 (from 0 to 3) . Conclusions Posterior pilon fractures are mostly caused by medium to high energy violence, resulting from a combination of rotational and vertical forces. Since there is a high risk of implant failure, the cannulated screw fixation from anterior to posterior is not recommended. Good clinical outcomes are observed in the cannulated screw fixation from posterior to anterior and the plate/cannulated screw fixation for posterior pilon fractures. Key words: Tibial fracture; Fracture fixation, internal; Treatment outcomes