Syndesmosis Injury Imparts A Large Negative Effect on Patient Reported Outcomes: A Systematic Review
Authors: Heifner John , Kilgore Jack E. , Nichols Jennifer A. , Reb Christopher W. 
Published: January 2022

Category: Trauma; Ankle; Sports Introduction/Purpose: Syndesmosis injuries are common, comprising up to 25% of all ankle sprains and being present in 35% or more of ankle fractures. Within the narrative of the syndesmosis literature, the substantial negative impact of syndesmosis injury is commonly described in intuitive yet qualitative terms. Therefore, a constructive criticism of the literature is to question how often and how well these reports have characterized the magnitude of the impact of the syndesmosis injury itself compared to confounding factors like concomitant injury. Indeed, such information particularly in aggregate, has the potential to influence clinical practice. Within this context, the objective of this systematic review was to assess how often and how well the literature has characterized the magnitude of syndesmosis injury. Methods: Included reports were grouped based on the setting in which syndesmosis injury was studied: (1) isolated syndesmosis disruption compared to lateral ankle sprain, (2) isolated syndesmosis disruption, (3) ankle fracture with concomitant syndesmosis disruption compared to ankle fracture with no syndesmosis disruption, and (4) ankle fracture with concomitant syndesmosis disruption without a comparison group with no syndesmosis disruption. Literature quality was assessed via the Modified Coleman Methodology Score (MCMS). Patients with and without syndesmosis injury were compared by independent sample t-tests using pooled values for specific patient reported outcome measures. Additionally, for these datasets, effect sizes were computed using Cohen's d. Results: Mean MCMS across all four groups was 59.9, indicating a moderate level of evidence. MCMS did not differ significantly between groups (p = 0.07). Analysis of reported outcomes indicated that syndesmosis injury has a significant (p = 0.007) effect and a large negative effect (effect size = 1.77) (Figure 1) on time to return to play when comparing athletes with isolated syndesmosis sprain to those with lateral ankle sprain. Additionally, analysis of ankle fracture patients indicated that syndesmosis injury has a large negative effect on functional outcomes (effect sizes > 0.80 for Olerud Molander and AOFAS scores), but little effect on pain (effect size = 0.14 for VAS pain). Studies which reported long term outcomes (mean 87 months) showed a very large negative effect (effect size 9.24) for Olerud Molander scores across 95 patients. Conclusion: In athletic populations, days missed due to syndesmosis disruption was statistically significant with a large effect size compared to lateral ankle sprain. Further, among ankle fracture patients, Olerud Molander and AOFAS scores indicate a large negative impact of syndesmosis disruption on functional outcomes despite a small negative impact on short term pain. These results indicate that the continued impact of this injury extends beyond the initial painful period and requires more attention. These patient-reported outcomes support the qualitative assertions that syndesmosis injury potentially imparts a large negative effect on clinical outcomes.