Size matters: The influence of the posterior fragment on patient outcomes in trimalleolar ankle fractures
Introduction
The incidence of ankle fractures is on the rise [1]. Retrospective studies have demonstrated that patients with bimalleolar fractures have a 4% risk of developing posttraumatic arthrosis, and in patients with trimalleolar fractures, the risk is as high as 34% [2]. Therefore, the anatomic reconstruction of the fracture is increasingly necessary the more complicated the fracture becomes.
Textbooks and many studies have indicated that in the case of posterior malleolar fracture (PMF) in trimalleolar fractures, osteosynthesis is indicated when the fracture affects at least 25% of the joint surface of the distal tibia. This statement originates from a study dated from 1940 [3], and to date, there are no substantial data to prove otherwise [4].
Clinical studies have found very different results [5, 6, 7, 8, 9, 10]. Most authors agree that the presence of a PMF worsened patient clinical outcomes. However, the debate continues whether small PMFs with less than 25% of joint surface affected should be anatomically reduced and fixed as well.
The available clinical studies are difficult to compare due to different emphases and different examination methods. Several studies showed that in cases of a PMF, a CT scan should be conducted to exactly determine its size [11, 12, 13].
Most retrospective studies have only evaluated patient outcomes on the basis of conventional X-rays.
Currently, CT scans in trimalleolar fractures provide more precise information about the size of the PMF and joint involvement.
However, there is a lack of studies on patient outcomes and the rate of post-traumatic arthrosis based on CT data.
Section snippets
Patient and methods
We conducted a retrospective analysis of all patients between 18 and 100 years of age with trimalleolar fractures who were operatively treated in our clinic between 2005 and 2011. An open reduction an internal fixation was conducted according to AO (Arbeitsgemeinschaft für Osteosynthesefragen) methods.
The follow-up was at least 6 months after operation, with an average follow-up of almost 2.5 years (range: 8.5–85.3 months). Eighty-one patients were eligible for inclusion, and all data were
Results
The available subjects consisted of 42 patients, 26 women and 16 men, with an average age of 52.8 years (range: 19–86 years). In 16 patients (35%) PMFs were fixated by osteosynthesis, 75% direct, 25% indirect.
After evaluation of the lateral X-rays, 54.8% (n = 23) of the patients had a PMF with a joint surface involvement below 25% (group I). This group consisted of 16 women and 7 men with a mean age of 54 years (range: 21–86 years). In this group, two patients (8.7%) received an osteosynthesis
Discussion
Stabilisation of ankle fractures continues to be a subject of interest to the scientific community [16, 17, 18].
The indication for surgery in a case of a PMF is the subject of controversy. Since a study from 1940, it has generally been accepted that a PMF in a trimalleolar fracture should be internally fixated when the size of the fragment exceeds 33% of the joint surface or, according to several other authors, if the fragment exceeds more than 25% [3, 4].
Many studies can be found in the
Conclusion
This review of the available current literature reveals a shortage of level A data concerning the surgical indication for internal fixation of the PMF in trimalleolar fractures.
Our study indicates a contradiction for the generally acknowledged hypothesis of screw fixation in fragments of a size at least 25% of joint contact area. An exact evaluation of CT images for posterior malleolar fractures in patients with trimalleolar ankle fractures is crucial for the decision to perform osteosynthesis
Role of the funding source
With the exception of financial support for writing assistance through a program for the promotion of women through the University of Muenster, no additional funding or sponsorship has contributed to the completion of this analysis of patient outcomes.
Writing assistance
American Journal Experts (AJE) provided writing assistance. Funding was provided by the medical deanship of Wilhelm's University Muenster for the promotion of women.
Conflict of interest statement
All authors disclose any financial and personal relationships with other people or organisations that could inappropriately influence this work. Examples of potential conflicts of interest include employment, consultancies, stock ownership, honoraria, paid expert testimony, patent applications/registrations, and grants or other funding.
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