Archives of Orthopaedic and Trauma Surgery - 2026-03-28 - Journal Article
Concurrent validation of a novel intraoperative navigation platform for total knee arthroplasty.
Demeulenaere M, Taylan O, Biały M, Van de Vyver A, Louwagie T, Peersman G, Scheys L
Topics
Key Takeaway
The Next-AR intraoperative navigation platform achieved implant alignment within a mean bias ≤1.5° of target across all six alignment parameters in cadaveric medially-stabilized TKA, with RMSE ≤2.3°.
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Summary
This cadaveric validation study assessed whether the Next-AR augmented reality navigation platform could accurately reproduce planned implant alignment and provide reliable real-time kinematic and ligament elongation data during mechanical alignment TKA. Seven fresh-frozen specimens underwent CT-based planning and medially-stabilized TKA (Medacta), with Next-AR outputs compared against Vicon bone-pin motion trackers as the gold standard. All six alignment parameters showed no statistically significant deviation from target (p≥0.12), and tibiofemoral kinematics and MCL/LCL elongation measurements were comparable between systems (p>0.18 for all reported bundles).
Key Limitation
The sample size of seven cadaveric specimens is insufficient to characterize error distribution across the range of deformity and soft-tissue conditions encountered clinically, limiting generalizability of the accuracy metrics.
Original Abstract
INRODUCTION
This cadaveric study aimed to assess the accuracy of the Next-AR navigation platform in terms of implant alignment, kinematics, and collateral ligament elongations in comparison to gold standard measurement tools.
MATERIALS AND METHODS
Computed tomography of 7 fresh-frozen legs were acquired for patient-specific guide design, identification of bony landmarks and collateral ligaments to acquire real-time feedback for bone resection, alignment and collateral ligament elongations using Next-AR system. The specimens underwent medially-stabilized TKA (Medacta) based on the mechanical alignment technique. The difference between target and achieved implant alignment parameters was assessed. The relative change in tibiofemoral kinematics, medial collateral ligament- (MCL), and lateral collateral ligament (LCL) elongations acquired with the Next-AR system were compared to reference values acquired with bone-pin mounted motion trackers (Vicon, UK) while performing quasistatic squatting in an ex vivo knee simulator.
RESULTS
The mean differences between achieved and target hip-knee-ankle angle, femoral varus, femoral flexion, femoral rotation, tibial varus, and tibial slope measured -1.5°, 0.5°, 0.07°, -0.14°, 0.79° and -0.36°, respectively, with no statistically significant differences found (p ≥ 0.12). Knee flexion (p=0.32) and valgus orientation (p=0.63), obtained from Next-AR and Vicon systems were comparable. Collateral ligament elongations derived from Next-AR exhibited similar values for the anterior bundle of MCL (p=0.18) and LCL in the anterior and middle bundles (p>0.3) obtained from the Vicon system.
CONCLUSIONS
Our findings showed that the Next-AR system achieved postoperative implant alignment close to the planned targets, with small systematic deviation (mean bias ≤ 1.5°), limited total error (RMSE ≤ 2.3°), and variability of paired differences ≤ 1.87°, while additionally providing quantitative real-time assessment of tibiofemoral kinematics and collateral ligament elongations.