Isocentric 3-dimensional C-arm imaging of component alignments in total knee arthroplasty with potential intraoperative and postoperative applications.

An intraoperative imaging tool for total knee arthroplasty could help avoid poor clinical outcomes related to malalignment. We investigated the feasibility of using isocentric (ISO-C) fluoroscopic imaging for this purpose. Three-dimensional ISO-C and computed tomographic (CT) images were acquired from 6 cadaveric specimens implanted with standard knee arthroplasty components and analyzed to determine rotational alignments. In comparison with standard CT measures, the ISO-C-based measures had overall accuracies (determined as root mean square error) of 0.8° and 1.3° and corresponding SDs of 1.3° and 1.4° for the femoral and tibial components, respectively. With ISO-C imaging, it is possible to measure rotational alignment in knee arthroplasty with accuracy and repeatability comparable with CT. Isocentric imaging has strong potential as an intraoperative tool to accurately align arthroplasty components.