Intraoperative landmarking errors and their avoidance in robotic-assisted total knee arthroplasty using the VELYS system.

UNLABELLED: While robotic-assisted total knee arthroplasty (rTKA) has been proven to achieve highly precise and reproducible radiographic results, its accuracy remains highly dependent on correct intraoperative landmark acquisition. This technical guide aims to provide practical guidance for intraoperative recognition of landmarking and gap balance assessment errors during rTKA using the image-free VELYSTM system. Based on the authors' clinical experience with this system, the most common pitfalls as well as their intraoperative recognition are highlighted. Special focus is set on pin placement, bone reference checkpoints and landmark acquisition, with practical intraoperative cues that allow surgeons to detect these errors intraoperatively before bone resections are performed. The present article should support early adopters of the VELYSTM system, with the aim of preventing precision inaccuracies. LEVEL OF EVIDENCE: Level V.