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Updated: Aug 5, 2026
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Published on: February 17, 2023
A standardized 3D modeling method to evaluate measurement accuracy of imageless computer-assisted total knee
T David Luo1, Sebastian B Braun2, James L Howard3
1Indiana Orthopedic Institute, 7230 Engle Rd, Fort Wayne, IN 46804, USA; Division of Orthopaedic Surgery, Department of Surgery, Schulich School of Medicine and Dentistry, Western University, London Health Sciences Centre - University Hospital, 339 Windermere Rd, London, ON N6A 5A5, Canada.
Background:
Computer-assisted total knee arthroplasty (CA-TKA) was developed to improve the accuracy and consistency of bone resections and implant positioning; however, evaluation of navigation system performance is often confounded by surgeon-dependent variability in landmark registration and surgical execution. Standardized methodologies that minimize these sources of variability remain limited. We sought to (1) develop a standardized experimental methodology that minimizes surgeon-dependent landmark variability when assessing CA-TKA systems and (2) demonstrate its application by quantifying measurement accuracy, alignment accuracy, and cut surface uniformity of two imageless navigation systems.
Method:
A standardized experimental model was created using CT-derived 3D-printed knee specimens incorporating predefined fiducial landmarks. Two imageless navigation systems, a semi-active robotic system and an optical navigation system, were evaluated in simulated TKA procedures. Embedded landmarks standardized landmark registration across trials. Following bone resections, high-resolution 3D scanning and geometric analysis were used to quantify resection parameters relative to ground-truth geometry. Measurement accuracy, alignment accuracy, and cut surface uniformity were assessed across repeated trials.
Results:
The standardized framework enabled consistent evaluation of resection geometry relative to predefined anatomical reference frames while minimizing variability related to landmark identification. Both systems demonstrated acceptable measurement accuracy for most parameters, although greater variability was observed in sagittal plane measurements. Both systems achieved high cut surface uniformity, with nearly all resected surfaces within 1 mm of the best-fit plane.
Conclusion:
This study presents a standardized experimental framework for evaluating CA-TKA systems while minimizing variability in landmark registration. The framework may facilitate future comparative evaluation of navigation and robotic technologies.
