An Oblique Trans-Syndesmotic Screw to Augment Fixation of Distal Fibula Fractures: A Technique Guide

Abstract

Category: Trauma; Ankle Introduction/Purpose: A subset of patients with low, transverse fractures of the lateral malleolus are at increased risk of malreduction and late loss of reduction. In patients with poor bone quality and transverse or short oblique fractures at or distal to the tibiotalar joint, distal fixation is often inadequate with a single interfragmentary lag screw. Furthermore, these fractures are susceptible to malreduction by pre-contoured locking plates. To address this, a technique was developed to augment fixation of the distal fragment and decrease the likelihood of loss of reduction. The senior author's technique for this procedure, as well as indications for the technique and a few representative cases, are provided. Methods: This technique involves placement of an oblique tricortical or quadricortical screw from the distal fibula into the tibia in an distal-lateral to proximal-medial direction. The screw is placed either outside of or through the distal-most hole of a one-third tubular plate placed in a neutralization position. The screw trajectory is similar to that of a typical syndesmosis screw in the sagittal plane but is aimed proximally rather than parallel to the tibial plafond. The screw enters the tibia at Chaput's tubercle, just lateral to the joint. The indications for this technique are transverse and short oblique Danis-Weber B distal fibular fractures in which there is inadequate purchase between the plate and the distal fragment. While the purpose of this screw is not to stabilize the syndesmosis, it can be used with other augmentation techniques, such as trans-syndesmotic screws, in high-risk patients with osteoporosis and/or neuropathy. Results: This technique has been used for many years by the senior author. There have been no implant failures (e.g. broken screws) or major complications associated with this technique. Three representative cases demonstrate appropriate indications and outcomes for this technique. These include patients with significant neuropathy or osteoporosis who present with a particularly troublesome fracture pattern (transverse fibular fracture at or below the level of the tibiotalar joint). This screw, along with any other syndesmotic screws, is removed at 3-4 months according to the senior author's protocol. Conclusion: A distal oblique trans-syndesmotic screw can be used to supplement current fibular fracture fixation constructs. It is easy to place under fluoroscopic guidance and generally is removed after fracture union, similar to standard syndesmosis screws. The use of this screw helps prevent the malreduction that can potentially occur when treating transverse or short-oblique Weber B distal fibular fractures with a locking plate. In our series of patients at a large urban tertiary referral center, this technique has produced good outcomes with no reportable complications.