A Randomized Controlled Trial Evaluating the Stability of the Distal Tibiofibular Syndesmosis With or Without Fixation of the Posterior Fragments in Bimalleolar or Equivalent Fractures

Study Flow and Procedures:

Screening and Randomization: Eligible patients presenting with recent bimalleolar ankle fractures (< 3 weeks) involving the posterior marginal fragment and syndesmosis (Bartoníček types 2, 3, or 4) are identified in the emergency/trauma department. Following written informed consent, participants are randomized into Group 1 (posterior marginal fragment osteosynthesis) or Group 2 (no posterior fragment osteosynthesis).

Preoperative Assessment: Comparative bilateral ankle X-rays and CT scans to confirm fracture classification and baseline metrics (fragment thickness > 2 mm, height > 6 mm).

Intraoperative Phase: Surgical management of the bimalleolar fracture according to assigned group. Intraoperative stress testing of the syndesmosis is performed to evaluate stability and record the necessity of trans-syndesmotic device placement.

Postoperative Follow-up: Day 1 to Week 6: Comparative bilateral CT scan to evaluate fragment and syndesmosis reduction. 3 Months & 12 Months: Clinical follow-up visits including comparative weight-bearing X-rays, evaluation of AOFAS score, and patient-reported questionnaires (MOXFQ, SF-12).

Postoperative complications (infections, neuropathic pain, fibular pain, flexor hallucis longus tendonitis) are systematically recorded throughout the 12-month follow-up.

Inclusion criteria

• Patient informed and written consent obtained
• Male or female participants aged 18 years or older
• Recent first-time ankle fracture (< 3 weeks prior to inclusion) involving the posterior marginal fragment and syndesmosis (Bartoníček 2, 3, or 4) confirmed on preoperative CT scan
• Fractured posterior marginal fragment with thickness > 2 mm and height > 6 mm in the sagittal plane on preoperative CT scan

Exclusion criteria

• Medical contraindication to surgery as assessed by the investigator based on risk-benefit evaluation
• High Tscherne grade soft-tissue injury score
• Recent lower-extremity surgery within the past 3 months
• Recurrent ankle fracture on the same side
• Patient deprived of liberty by judicial or administrative order
• Patient not affiliated with or beneficiary of a national social security scheme
• Patient unable to understand spoken or written French
• Patient whose geographical residence is incompatible with close in-person study follow-up
• Adult patient unable or unfit to give informed consent
• Woman of childbearing potential not using effective contraception
• Pregnant or breastfeeding woman