CT-Based Mediolateral Measurement of the Talus as a Useful Tool in Preoperative Planning of Total Ankle Arthroplasty via the Transfibular Approach.

Abstract

Total ankle replacement (TAR) is an established option for end-stage ankle arthritis, providing pain relief and functional recovery. Precise implant sizing and alignment are crucial for long-term prosthesis survival. In the transfibular approach, determining the appropriate talar component size intraoperatively can be challenging, especially in the presence of residual deformities. To assess the correlation between preoperative CT-based mediolateral (ML) talar width and the final implanted talar component size in transfibular TAR. Retrospective analysis of consecutive primary TAR cases. Fifty primary TARs using non-cemented Zimmer Trabecular Metal implants via a transfibular approach were reviewed. Cases requiring additional procedures were excluded. Preoperative CT scans were used to measure ML talar dome width at its highest convex point on coronal images. Measurements were performed by a blinded radiologist and compared with intraoperatively implanted component sizes. CT-based ML width showed excellent correspondence with implanted sizes. The mean difference between CT measurements and implanted components was 0.0 mm (SD 1.12 mm; range -2.4 to +2.4 mm). Exact matching occurred in 38/50 cases (76%), and all cases were within ±1 size. The maximum deviation of 1.2 mm remained below half a size increment. Preoperative CT-based ML talar measurement is a reliable, reproducible, and cost-effective tool for predicting talar component size in transfibular TAR, improving preoperative planning and intraoperative decision-making. III.