Elsevier

Injury

Volume 46, Supplement 4, October 2015, Pages S109-S113
Injury

Size matters: The influence of the posterior fragment on patient outcomes in trimalleolar ankle fractures

https://doi.org/10.1016/S0020-1383(15)30028-0Get rights and content

Abstract

Introduction

Ankle fractures are increasing in incidence. The more complicated the lesion is, the higher the risk of developing posttraumatic arthrosis. Severe posttraumatic arthrosis results in a reduced quality of life. Therefore, the treatment of a trimalleolar fractures is crucial. However, the treatment guidelines for posterior malleolar fractures (PMF) are still based on recommendations from 1940. Only a few retrospective studies have been conducted, which analysed patient outcomes based on lateral X-rays of the ankle. The purpose of this retrospective analysis was to survey patient outcomes in relation to the size of the PMF on the basis of CT-scans.

Methods

We retrospectively examined 42 patients with trimalleolar fractures with an average follow-up of 2.5 years. Twenty-four patients (57%) received a CT scan of the ankle joint. The radiologic images were analysed for the size of the PMF and the involvement of the joint surface using lateral X-rays and available CT images.

We examined all 42 patients clinically and radiologically, and estimated the grade of arthrosis of the ankle in accordance with the Bargon Score and assigned AOFAS Scores for each patient.

We divided our patients into different groups according to the size of their PMF and evaluated patient outcomes in accordance with the compiled data first on the basis of X-ray data and then on the basis of CT data.

Results

Comparing the measurement results by two different radiologic methods revealed that CT results in a more precise determination of PMF size in contrast to lateral X-rays, by which measurements were generally overrated.

The statistical evaluation of our data demonstrated that patients with an osteosynthesis of the PMF and a PMF size of >25% showed signs of posttraumatic arthrosis but had better outcomes in accordance to the AOFAS score. All results were not significant.

Conclusion

An exact evaluation of CT images of posterior malleolar fractures in patients with trimalleolar ankle fractures is crucial for the decision to perform an osteosynthesis of the PMF and, therefore, an analysis of patient outcomes. The results of previous studies should be evaluated cautiously due to missing CT data. To date, this is the largest retrospective patient series of patient outcomes based on CT data.

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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