SLR - October 2022 - Garrett Biela, DPM
Reference: Kubik JF, Rollick NC, Bear J, Diamond O, Nguyen JT, Kleeblad LJ, Helfet DL, Wellman DS. Assessment of malreduction standards for the syndesmosis in bilateral CT scans of uninjured ankles. Bone Joint J. 2021 Jan;103-B (1):178-183. doi: 10.1302/0301-620X.103B1.BJJ-2020-0844.R1. PMID: 33380196.Level of Evidence: 3
Scientific Literature Review
Reviewed By: Garrett Biela, DPM
Residency Program: University of Florida Health Jacksonville, FL
Podiatric Relevance:
Malreduction of the syndesmosis following surgical treatment of ankle fractures can lead to a worsened prognosis and a need for further surgery. Historically, post-operative radiographs and CT scans have been the traditional method of diagnosing syndesmotic malreductions despite the lack of peer reviewed literature justifying its effectiveness. Further investigation of syndesmotic malreduction as well as the advocacy for advanced imaging may lead to an improved understanding and more efficacious diagnostic methods to better treat this complication.
Methods:
The retrospective, comparative study reviewed 213 bilateral CT scans in subjects with no prior syndesmotic injury. Five measurements were obtained of each limb by three independent observers: anterior syndesmotic distance; posterior syndesmotic distance; central syndesmotic distance; fibular rotation; and sagittal fibular translation. These findings were compared to the contralateral limb in each subject as well as previous standards and statistical analysis was performed.
Results:
The analysis shows that 35% (N = 75) of normal ankles would be considered malreduced by current standards. There was a difference of >2mm between anterior and posterior displacement in each of limb of 89% (N = 190) of subjects. Only 23% (N = 50) of patients had one parameter within normal limits. Furthermore, fibular rotation had the lowest false positive rate (6%), while posterior syndesmotic distance had the highest at 15%.
Conclusion:
The statistical analysis shows that the current standards for diagnosis on syndesmotic malreduction is a poor indicator of pathology. This study shows that 35% of normal ankles would be diagnosed as malreduced. Additionally, they found that comparing anterior and posterior syndesmotic distance has little diagnostic value. These findings suggest further protocols and research on this topic is necessary to appropriately identify adequate reduction standards.