VELYS™ robot-assisted unicompartmental knee arthroplasty: indications, operative technique, and practical considerations

Background: While historical selection criteria for unicompartmental knee arthroplasty (UKA) were highly restrictive, recent consensus from the British Association for Surgery of the Knee and the European Knee Society has expanded indications, suggesting 20% to 50% of arthroplasty candidates may be eligible. Despite clinical advantages over total knee arthroplasty, UKA remains associated with higher revision rates, often attributed to surgeon-dependent factors such as malalignment and improper component positioning.

Objective: This article describes the surgical technique and clinical rationale for using the VELYS™ robotic-assisted system in the implantation of the Sigma™ Partial Knee prosthesis for medial or lateral femorotibial osteoarthritis.

Key Points: The image-free robotic system utilizes optical navigation and a mobile station with an integrated saw to enhance precision. The procedure involves anatomical landmark registration, surface mapping for three-dimensional bone modeling, and dynamic ligamentous gap assessment via the ACCUBALANCE™ tool. Intra-operative planning allows for precise adjustment of implant size, orientation, and joint line restoration. Robotic assistance is utilized for the transverse tibial and femoral cuts, while the sagittal tibial cut remains manual. Evidence suggests that robotic integration improves alignment accuracy and patient satisfaction, potentially offsetting higher initial costs by reducing long-term revision rates and complications.

Conclusion: Robotic-assisted UKA provides a standardized, precise method for implant positioning and ligamentous balancing. By adhering to modern indications and utilizing robotic technology to minimize technical errors, surgeons may achieve clinical outcomes and survivorship rates comparable to total knee arthroplasty.