SLR - June 2012 - Tamala Walton
Reference: Harri Pakarinen, Tapio Flinkkila, Pasi Ohtonen, Pekka Hyvonen. Syndesmotic Fixation in Supination-External Rotation Ankle Fractures: A Prospective Randomized Study. Foot and Ankle International. 2011; 32(12) 1103-1109
Scientific Literature Review
Reviewed by: Tamala Walton, DPM
Residency Program: OCPM & University Hospital Richmond Heights Medical Center
Podiatric Relevance:
Supination-external rotation ankle fractures are the most common fractures to the distal fibula. There may be undetected syndesmotic disruption in these types of injuries. The purpose of this study was to determine if transfixion of an unstable syndesmosis is needed in supination-external rotation ankle fractures.
Methods:
A prospective study was performed including 140 patients designated with having a unilateral Lauge-Hansen supination-external rotation type four ankle fracture. All fractures were fixated and then assessed using the 7.5 Nm standardized external rotation stress test. Both ankles of the patient were evaluated under fluoroscopy intra-operatively for comparison. A positive stress test was defined as a difference of more than 2 mm side-to-side in the tibiotalar or tibiofibular clear space on a mortise radiograph. If the test was positive, the patient was randomized either into the group to receive transfixion of the syndesmosis or no fixation. Randomization was performed with a computer-generated list that was created by one of the authors not involved in the treatment process. All syndesmosis fixations were completed with a 3.5 mm tricortical screw. Clinical outcomes were measured using the Olerud-Molander scoring system, RAND 36-item Health Survey, and Visual Analogue Scale to assess pain and function after a minimum one year follow-up.
Results:
The study was terminated before completion due to that fact that there was a low incidence of syndesmotic injury among the study population. The analysis also showed no significant differences between the randomized groups. Twenty-four of the 140 patients had a positive stress test after malleolar fixation. The tibiotalar clear space was positive three times and the tibiofibular clear space was positive seven times on the stress views. Both spaces were positive at the same time on stress views a total of 14 times. There was no significant difference between the groups after assessing the Olerud-Molander functional score, VAS scale measuring pain and function, or the RAND 36-item Health Survery assessing pain or physical function at the one-year follow-up. There were no differences with regard to the tibiotalar clear space (mean, 3.5 mm versus 3.2 mm p=0.34), and the tibiofibular clear space (mean, 5.4 mm versus 5.5 mm, p= 0.41) between the group that received syndesmotic screw fixation and the group that did not. Ankle joint range of motion at the 12-week follow-up was similar between the two groups, group with syndesmotic screw or no fixation, respectively (mean dorsiflexion degrees, 22 versus 23, p=0.34; mean plantarflexion, 41 versus 36, p=0.58).
Conclusions:
The authors concluded that 17 percent of the syndesmoses in the 140 patients were unstable, showing that syndesmotic injuries in a supination-external ankle fracture is relatively rare. There was no significant difference between functional outcome in patients with transfixion of the syndesmosis and those without fixation in the supination-external ankle fracture. The outcome of this study is met with limitations due to the fact the authors terminated the study prior to completion because of the low rate of syndesmosis injuries. It was determined that through post hoc power analysis that at least 199 patients were needed per randomized group to perhaps show a statistical significant difference in the Olerud-Molander score bewteeen the groups. It is recommended that future studies include a larger study population with objective i.e. radiographic as well as subjective analysis at follow-up.