Does Syndesmosis Screw Breakage Affect Patient Outcomes? A Retrospective Comparative Study

Abstract

Category: Ankle Introduction/Purpose: Metal screw fixation remains a common and effective way to repair syndesmotic injuries. They are inexpensive, familiar, and provide superior torsional resistance to sagittal translation compared to other fixation modalities. Symptomatic screw breakage is one of the most common complications of metal screw fixation. Routine removal remains unsupported by literature. Consequently, many patients retain broken screws and are at risk for pain; particularly when the breakage occurs within the tibia or the fibula. The purpose of this study is to analyze outcomes of patients with intact syndesmosis screws and those with syndesmosis screw breakage. Methods: A total of 176 patients (260 screws) with syndesmotic disruption treated with syndesmosis screw fixation were included in the study. Half of the patients had broken syndesmosis screws while the other half had intact syndesmosis screws. Basic patient demographic data was collected including BMI, age, and gender. Further collection of patient comorbidities was compiled using two comorbidity indices (Charlson, Elixhauser). Outcome analysis included revision rate, removal secondary to pain, complication rate, range of motion deficits, and patient pain scores. In patients who had their screws removed, further analysis was conducted to compare strength, range of motion deficits, complication rates, pain scores and revision rates between the intact and breakage group. Results: BMI averages of 33.64 (SD=8.77) and 30.64 (SD=6.76) were seen in breakage and intact group, respectively. A complication rate of 24.0% was seen the breakage group versus 36.1% in the control group. Revision rates of 12.4% and 20.10% were seen in the breakage and control group, respectively. Range of motion deficits were seen in 50.2% in the intact group and 39.7% in the breakage group (P = 0.2253). Removal secondary to pain occurred in 60.30% (n = 73) in the broken group compared to 24.5% (n = 34) in the control group. Decreased complication rate (P =.002), increased BMI (P = <.001), and increased risk of removal secondary to pain (P = <.001) were all associated with screw breakage. Following screw removal, no difference was seen in range of motion, pain scores (P =.003) and complications rates (P = 0.147) were higher in the intact group. Conclusion: Metal screw fixation remains a popular treatment of syndesmotic disruption. Many patients retain broken screws and intact screws which can be associated with future complications. Patients with syndesmosis screw breakage are a high comorbid population. Syndesmosis screw breakage is associated with decreased complication rates, increased BMI, and increased risk of eventual removal secondary to pain. Range of motion deficits were seen more commonly when in patients with intact syndesmosis screws. Additionally, revisions rates were higher in the intact group compared to the breakage group. Following screw removal, the intact group had a non-statistically significant increase in complication rate and range.