gms | German Medical Science

Objectives: Ankle sprains and fractures are common injuries in orthopedic and trauma surgery and are often combined with acute syndesmosis tear. The two most frequent surgical procedures for an unstable distal tibiofibular joint are the static screw fixation and the transfixation with the flexible, dynamic TightRope® (Arthrex, Naples, FL, USA) suture button device. Various studies have compared the two devices regarding clinical, radiological and biomechanical outcomes. However, to our knowledge, no study has yet used in vivo instrumented 3D gait analysis. We hypothesized that TightRope® fixation would perform better or similar to screw fixation in terms of biomechanical and clinical outcomes.

Methods: Patients were prospectively randomized to either screw fixation or TightRope® fixation. Subsequently, all patients received the same follow-up rehabilitation protocols and consultations at 6 and 12 weeks, as well as 6 and 12 months after surgery. At everyfollow-up appointment, the questionnaires Olerud Molander Ankle Score (OMAS), Foot and Ankle Outcome Score (FAOS), 12-item Shortform health survey questionnaire (SF-12) and pain on a Visual Analogue Scale (VAS) were performed to objectify pain, ankle function and symptoms, as well as quality of life. On the 6months follow-up visit, instrumented 3D gait analysis was conducted to analyze maximum active dorsiflexion, plantarflexion, torque and power during gait in both the affected and unaffected ankle.

Results and conclusion: Twenty-five patients each in TightRope® (T) and screw (S) fixation group completed gait analysis. Mean values of TightRope® fixation group for maximum torque were significantly better in the affected (T: 1.40 ± 0.21 Nm, S: 1.23 ± 0.30 Nm; p = .023) and unaffected ankle joint (T: 1.52 ± 0.20 Nm, S: 1.37 ± 0.27 Nm; p = .035). The mean difference between the affected and unaffected ankle joint of each patient was found to be significantly higher in the screw fixation group concerning the active plantarflexion (T: 1.52 ± 0.20°, S: 1.37 ± 0.27°; p = .035). None of the other gait analysis parameters were significant. Questionnaire results showed either a significant superiority of the TightRope® fixation group or nonsignificant differences.

Our study could demonstrate that TightRope® fixation has better or similar biomechanical and clinical outcomes compared to screw fixation when post-operative treatment regimen was uniform. Further prospective randomized studies are needed that focus on biomechanical differences during gait as well as clinical outcomes in case of earlier weight-bearing after TightRope® fixation.