Validation of surgical reduction criteria after syndesmosis injuries via/using instrumented 3D movement analysis

Status:

completed 03/2023

Aims:

A non-anatomical reposition after syndesmotic injuries can lead to post-traumatic changes and arthrosis or functional limitations as well as pain which might result in long-term or permanent degenerative changes, especially at the ankle. In order to objectify the care of this joint, various criteria for a surgical treatment were established. It is postulated that if these criteria are fulfilled, a better clinical outcome will be reached for the patient, medium and long term. These reposition criteria were examined quantitatively in an initial study using questionnaires and shown to be useful, however, no validation using quantitative measures have been undertaken yet.

The aim of this study was, therefore, to extend the results of previous research on acute syndesmosis injuries and to confirm them with quantitative measurements. It was assumed that patient group I, whose syndesmosis in the intraoperative 3D scan shows an anatomically correct reduction according to the established criteria, resulted in a clinically better outcome in medium and long-term than patient group II with non-anatomical reduction. An optimal result would imply freedom from discomfort or pain, no restriction in the active and passive range of motion in simple and complex movements compared to the opposite side, and also no loss of strength of the muscle groups involved.

Activities/Methods:

This study included a retrospective case-control study design. The intraoperative 3D imaging data of patients included for ankle fracture with concomitant syndesmotic injury were reviewed. Patients from the previous study were invited to a follow-up examination in the Motoriklabor. In addition, further patients who were treated at the BG Clinic (2011-2019) were contacted in order to achieve a larger case number. Of 804 possible patients only 58 patients were finally included and allocated to two groups depending on whether the criteria for radiologically optimal reduction were met (39 patients) or not (19 patients). Criteria for optimal reduction were composed of objectively measured and subjectively rated data. After undertaking the Olerud/Molander ankle score, a gait analysis and several active function tests using 3D motion capture (infrared cameras, force plates) were performed in order to evaluate kinematic (e.g. joint angles) and kinetic (e.g. joint moments) differences between both groups.

Results:

Even though no significant differences were observed in the present study, clear clinically relevant tendencies for a better functional outcome after criterion-appropriate surgery were shown, especially with regard to the maximum dorsal extension achieved in the functional tests and the time-to-stabilisation during balance tasks. Together with the significantly larger proportion of patients who were repositioned according to the criteria and who were able to perform the balance exercises at all, this indicates that the functional outcome tends to correlate with the repositioning accuracy. A secondary finding of the study was the lateral difference that still existed in both groups, especially during the more complex functional tests. This highlights the importance of instrumental motion analysis for clinical diagnostics and therapy in order to objectively determine whether patients carry functional deficits relevant to everyday life even after a longer period of time from the injury.

A limitation of the study is the different distribution of the groups (39 vs. 19 patients), which was partly due to the strict inclusion and exclusion criteria and the Corona pandemic. Based on these results, a prospective multicentre randomised controlled study with subgroup analysis is recommended for the future in order to enable an evaluation of the individual reduction criteria with a larger number of cases.

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