Image-guided total knee arthroplasty

Over the past decade, image guided technology in total knee arthroplasty (TKA) has made gains in both acceptance and use by orthopaedic surgeons. This technology has quickly expanded with the development of several computer-based navigation systems, patient-specific instrumentation, and robotic platforms. This review covers the major clas-sification scheme of computer assisted orthopedic surgery systems based on the imaging modality utilized (preoperative computed tomographic imaging, intraoperative fluoroscopy, imageless) and the level of the surgical system's automation (passive, active constrained robots, autonomously active robots). Each system is described with reference to clinical performance to date and is evaluated. Particular emphasis is focused on passive computer navigation systems and how this technology impacts component orientation and alignment, clinical outcomes, perioperative complications, operative time, and costs. Recent developments in patient-specific technology and robot assisted systems are also discussed. At the current time, computer assisted orthopedic surgical systems appear to generally increase accuracy in mechanical alignment and component positioning with reduced outliers, potentially decrease embolic phenomenon, and help facilitate specific types of surgery. However, these advantages must be weighed against the potential for increased costs, operative time, and unique complications. Long-term outcome data are currently lacking and will be necessary to define the role of image guidance in TKA.