A Retrospective Comparison of Single Screw vs Dual Screw Fixation for Treatment of Medial Malleolus Fractures

Abstract

Category: Trauma; Ankle Introduction/Purpose: Medial Malleolus Fractures (MMF) are frequently managed by orthopaedic surgeons and are one of the most treated fractures of the ankle. Many approaches to fixation are described in the literature. Currently, there is a lack of consensus on the number of screws used in fixation when attempting lag-screw fixation of MMF. Aim: To compare the outcomes of MMF with patients between fractures which have either undergone single-screw (SS) or dual-screw (DS) fixation. Methods: Patients who had undergone surgical fixation of their MMF were identified from 2012 to 2022, using electronic patient records. Analysis of their pre-operative, intra-operative and post-operative radiographs was performed to determine the initial type of injury and then surgical outcomes relating to non-union, malunion and whether revision surgery was required. Results: A total of 653 patients were identified across a 10-year period. There were 271 patients (41.50%) in the SS group and 382 patients in the DS group (58.50%). When comparing the outcomes of SS compared to DS, a non-union rate of 19.19% (52/271) was found in the SS group as compared to 18.85% (72/382) in the DS group. There was a malunion rate of 11.07% (30/271) in the SS group as compared to 3.93% (15/382) in the DS group, which was statistically significant (p <.001). On multi regression analysis, the other factors which gained significance for development of non-union was non fixation of syndesmosis (p= .039), ankle dislocation on arrival (p <.001) and non-restoration of fibular length (p <.001). Conclusion: Use of a single screw rather than double screw showed a significant increase in non-anatomical reduction but did not increase non-union or reoperation rate. Syndesmosis fixation has clear impact on the stresses on the medial malleolus and should have a low index of suspicion of injury and fixation.