Use of 3D Weight-Bearing CT Syndesmotic Assessment in Surgical Decision Making

Research Type: Level 2 - Prospective comparative study, Meta-analysis of Level 2 studies or Level 1 studies with inconsistent results Introduction/Purpose: Three-dimensional (3D) weight-bearing computed tomography (3D WBCT) has demonstrated superior sensitivity in detecting subtle syndesmotic instability compared to conventional imaging modalities. However, despite its diagnostic advantages, limited research has explored whether the utilization of volumetric 3D WBCT measurements impacts clinical decision-making, particularly in altering surgical planning. This study aimed to evaluate whether patients who underwent 3D WBCT following ankle syndesmosis injury subsequently received surgical treatment and if 3D WBCT measurement could have the potential to help with the treatment decision making. Methods: This study prospectively included 32 consecutive patients with suspected syndesmotic instability following ankle trauma who underwent bilateral WBCT at the request of an expert foot and ankle surgeon. All patients had prior plain radiographs. Syndesmotic assessment was independently conducted by expert musculoskeletal radiologists. Additionally, we performed a novel 3D measurement (Ashkani-Esfahani et al. 2021) using our semi-automated Ankle Insight 3D platform for bilateral comparison. Patients were followed to determine whether they underwent surgery. We compared the surgeon’s final decision with radiologist interpretations and our 3D WBCT analysis. Statistical analysis included the calculation of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for each imaging modality in predicting the need for surgical intervention. Our analysis aimed to identify the diagnostic performance of 3D WBCT compared to conventional image interpretation methods in guiding surgical management. Results: 3D WBCT had the highest precision, NPV, and sensitivity compared to 2D WBCT and plain radiographs. Table 1 summarizes modality performance. Conclusion: Our study demonstrated that 3D WBCT is the most effective imaging measurement predicting the need for surgical intervention in ankle syndesmosis instability. WBCT volume offers the best balance of sensitivity (56%) and specificity (87%). 2D WBCT measurements exhibited high specificity (92%) but poor sensitivity (25%), limiting its reliability in detecting unstable syndesmosis injuries requiring surgery. Radiographs performed poorly as a predictor of surgical intervention, with a low sensitivity and PPV, making them inadequate for surgical decision-making. Thus, 3D WBCT may serve as a valuable tool in optimizing preoperative assessment and surgical planning in patients with syndesmotic instability, particularly when equivocal.