Ankle Syndesmosis Fixation by Antibiotic Releasing Bioabsorbable Screw

Overview

This single-center randomized trial evaluates the efficacy and safety of a new bone screw (antibiotic releasing bioabsorbable screw) in fixation of syndesmosis in patients with Weber C-type ankle fractures. The comparison is made to subjects treated by conventional metal screw fixation of the syndesmosis. The primary objective is to show that the antibiotic releasing bioabsorbable screw is at least as good as the routinely used metal screw in prevention of syndesmosis widening in patients with Weber C-type ankle fractures. The secondary objective is to show that the clinical outcome of the ankle fracture treatment is equal between patients treated by the antibiotic releasing bioabsorbable screw and the conventional metal screw.

This is a randomized parallel-group single centre study. All the patients enrolled will have an acute, closed Weber C-type ankle fracture. The ankle syndesmosis will be fixed using the new medical device (antibiotic containing bioabsorbable screw) or the routinely used device (metal screw). The investigational antibiotic containing bioabsorbable screw for ankle syndesmosis repair (the thread diameter 4.5 mm) will be made of bioabsorbable poly(lactide-co-glycolide) (PLGA) 80:20 and ciprofloxacin, which is a bactericidal antibiotic. The main purpose of the screw is to prevent syndesmosis widening after Weber C-type of ankle fracture. The secondary function of the screw is to reduce the risk for colonization of the implant with bacteria and subsequently prevent biomaterial-related infection. In the control group, a stainless steel screw will be used. All patients will receive the standard of care for concomitant fractures and other injuries of the ankle. The key variables in the assessment will be radiostereometric (RSA) measurements of the syndesmosis width, CT imaging of the ankle mortise and standard radiographic evaluation of the syndesmosis width and ankle mortise. Clinical outcome of the ankle fracture treatment will be measured using standardized outcome questionnaires (RAND-36, AAOS Foot and Ankle Outcome Instrument, Olerud and Molander score, VAS pain scale). The follow-up of the patients will be 52 weeks. The metal screw will be removed 8 weeks after fracture surgery. The expected mechanical integrity of the bioabsorbable screw is 6 - 8 weeks, while the complete absorption time of the bioabsorbable screw in human body is expected to be approximately two years