Patterns and Implications of Early Syndesmotic Screw Failure in Rotational Ankle Fractures.

Abstract

The purpose of this study was to identify characteristic patterns of syndesmotic screw (SS) failure, and any effects on clinical outcome. A retrospective study was performed using a consecutive series of patients treated with open reduction and internal fixation with trans-syndesmotic screws for unstable ankle fractures with syndesmotic injury between 2015 and 2017. Patient demographics, fracture characteristics and classification, rates and patterns of trans-syndesmotic screw breakage, and backout were analyzed. Functional outcome was assessed using passive range of motion (ROM) and Maryland Foot Score (MFS). A total of 113 patients (67%) had intact screws and 56 patients (33%) demonstrated either screw breakage or backout. Patients with SS failure were younger (<i>P</i> = .002) and predominantly male (<i>P</i> = .045). Fracture classification and energy level of injury were not associated with screw failure. Nine screws (11%) demonstrated backout (2 also broke) and 56 other screws broke. There was no association between the number of screws or cortices of purchase and screw failure. There was a trend toward a higher proportion of screw removal (20%) in this failed SS group compared with the intact SS group (12%) (<i>P</i> = .25), but with similar ankle ROM and MFS (<i>P</i> > .07). Syndesmotic screw breakage was common in younger, male patients. Despite similarities in ankle range of motion and clinical outcome scores to patients with intact screws, there was a trend towards more frequent screw removal. This information can be used to counsel patients pre- and postoperatively regarding the potential for screw failure and subsequent implant removal. Level III, retrospective case-control study.