The accuracy of acquisition of an imageless computer-assisted system and its implication for knee arthroplasty

The majority of the current computer-assisted systems (CAS) for knee prosthetic surgery require the acquisition of points using a tracker detected by an infrared camera. Two types of measurements are then essential: angles and distances. The goal of this study was to evaluate the accuracy of the data obtained during computer-assisted surgery using an in vitro protocol. Two models were developed to locate precisely both points (120 acquisitions) and distance measurements (144 acquisitions) and angles (170 acquisitions) with an image-free CAS using an infrared optical camera. For validation, a precise coordinate 3D measurement device was used to assess the accuracy of CAS acquisitions. The points, distances and angles had a mean error respectively of 0.638 mm (0.244 mm to 0.931 mm), 0.355 mm (0.001 mm to 1.338 mm) and 0.39° (0.06° to 0.69°). For all these acquisitions, the mean error was statistically less than 1mm or 1° (p