Abstract
Advanced imaging used in robotic-assisted total knee arthroplasty (TKA), such as computed
tomography (CT)-based three-dimensional (3D) planning, may provide an accurate means
of implant sizing preoperatively. The purpose of this study was to examine preoperative
CT-based implant planning accuracy for robotic-assisted TKA in patients who have (1)
varus deformities, (2) valgus deformities, (3) neutral alignment, and (4) retained
hardware. A total of 393 patients underwent a robotic-assisted TKA by a single surgeon
received preoperative CT scans. The surgeon reviewed the CT-based model preoperatively
and recorded the expected size of the components. The final implants used in each
case were recorded and compared with the surgeon's preoperative plan. In all groups
of patients, the surgeon's CT-based implant plan was within one size of the implant
utilized 100% of the time for both the tibiae and femora. Overall, the surgeon was
exactly matched in 319 (81%) and 315 (80%) cases for the femoral and tibial components,
respectively. For the femoral component, the mean age for patients in whom the original
plan was exactly matched was younger than those whose implants were upsized and older
than patients those implants were downsized (p = 0.024). Other patient demographics and preoperative knee alignment were not associated
with predictive accuracy for femoral or tibial components. Our results demonstrate
how preoperative CT-based, 3D planning for robotic-assisted TKA is accurate to within
one size of the components in every case (100%), and exactly matched in 80%. The results
of this study are important because they demonstrate how CT-based preoperative implant
planning for TKA is reliable and accurate across all native knee alignments and other
patient-specific factors. In addition, they build on a previous study by the same
single surgeon, demonstrating that predictive ability can improve over time. This
may be important as we move toward more outpatient surgery with less ability for prostheses
inventory at ambulatory sites.
Keywords
osteoarthritis - knee - arthroplasty - computed tomography
