A cadaveric investigation of the accuracy of a new, computer-assisted navigation system for total knee arthroplasty: A comparison with computed tomography imaging

Despite the success of total knee arthroplasty (TKA), malalignment continues to be a problem which often leads to post-operative complications. The aim of this study was to investigate the accuracy of a novel, imageless, optical surgical navigation tool to assist with the alignment of femoral and tibial cuts performed during total knee arthroplasty. Six board-certified orthopedic surgeons performed TKA procedures on 9 cadavers (17 knees total), using a novel, imageless navigation system (Intellijoint KNEE, Intellijoint Surgical). Varus/valgus, femoral flexion, tibial slope, and rotation measurements from the device were compared with angular measurements calculated from post-operative computed tomography (CT) images. Navigation measurements were highly correlated with those obtained from CT scan in all three axes. For the femoral cuts, the absolute mean difference in varus/valgus was 0.83° (SD 0.46°, r = 0.76), in flexion was 1.91° (SD 1.16°, r = 0.85), and in rotation was 1.29° (SD 1.01°, r = 0.88) relative to Whiteside’s line and 0.97° (SD 0.56°, r = 0.81) relative to the posterior condylar axis. For the tibia, the absolute mean difference in varus/valgus was 1.08° (SD 0.64°, r = 0.85), anterior/posterior slope was 2.78° (SD 1.40°, r = 0.60), and rotation was 2.98° (SD 2.54°, r = 0.79). Intraoperative monitoring with the imageless navigation tool accurately measures femoral and tibial cuts in TKA and may help to increase component alignment.