A Novel Mixed-Reality System Has Comparable Accuracy to a Robotic System in Total Knee Arthroplasty

Background: Mixed-reality total knee arthroplasty (MR-TKA) allows for simultaneous viewing of the surgical field and overlaid data to potentially match the accuracy of robotic-assisted TKA (RA-TKA) but with minimal footprint and open platform compatibility. This study compared the in vivo accuracy of this novel MR-TKA system to a well-established RA-TKA system. Methods: Data was collected from 40 TKA cases utilizing an FDA-cleared MR-TKA system and 40 modern imageless RA-TKA cases from June 2024 to February 2025. Deviations from intraoperative planned coronal femoral, tibial, and hip-knee-ankle alignment to actual alignment, measured on postoperative radiographs, were compared. Mean variance values between the thickness of planned and caliper-measured resections were also compared. Operative times and postoperative complications were collected. Results: Mean angular variance in femoral (0.9 vs 0.8°, P = .525), tibial (0.8 vs 0.7°, P = .458), and hip-knee-ankle (1.1 vs 0.8°, P = .078) coronal alignment were not significant between RA-TKA and MR-TKA cohorts, respectively. Mean depth variance in distal femoral (medial 0.6 vs 0.8 mm, P = .083; lateral 0.6 vs 0.8 mm, P = .078), posterior femoral (medial 0.6 vs 0.8 mm, P = .246; lateral 0.7 vs 0.6 mm, P = .464), and tibial (medial 0.6 vs 0.7 mm, P = .482; lateral 0.7 vs 0.7 mm, P = 1.00) resections were not significant. Mean operative time was longer with MR-TKA (107 vs 95 min, P = .002). Conclusions: A novel MR-TKA system provides similar accuracy in both resection depths and component alignment compared to an imageless RA-TKA platform.