Comparison of lag screw fixation on posterior malleolar fractures in different directions and screw-related complication

Abstract

Objective To compare the effects of indirect reduction, percutaneous anterior posterior screw and direct reduction, posterior anterior screw in the treatment of posterior malleolus fracture. Methods A retrospective analysis was made on 58 patients with posterior malleolus fracture treated by cannulated screw fixation from January 2013 to December 2017 in the Department of Orthopedics, Affiliated Hospital of Guangdong Medical University.They were divided into anterior and posterior screw group (26 cases) and posterior and anterior screw group (32 cases) according to different treatment methods.The incidence of poor screw position and other complications were compared between the two groups.Health status and ankle function at the last follow-up were compared between the two groups. Results The incidence of screw malposition in the anterior and posterior screw fixation group was 23.08%(6/26), which was significantly higher than that in the posterior screw fixation group was 3.85%(1/32). The difference between the two groups has statistically significant (χ2=5.381, P=0.020); there was no significant difference in other complications such as infection, traumatic arthritis, bone nonunion (all P>0.05). At the last follow-up, the OMA scores of AP group were (80.70±8.16)and PA group were(75.23±9.33), There were significant differences between the two scores(t=2.240, P=0.029), the AOFAS scores of AP group were (80.57±7.25) and PA group were(75.38±10.19), There were significant differences between the two scores(t=2.110, P=0.039). Conclusion The Indirect reduction and percutaneous anterior and posterior screw treatment have a high incidence of malposition of the screw, which has an impact on ankle function.Direct reduction and posterior and anterior screw fixation can significantly reduce the incidence of malposition of the screw and obtain better functional results. Key words: Posterior malleolus fracture; Indirect reduction; Poor screw position; Ankle function