Precise landmarking in computer assisted total knee arthroplasty is critical to final alignment

Area of Science:

• Orthopedic Surgery
• Medical Device Technology
• Biomechanical Engineering

Background:

• Image-free computer navigation is utilized in total knee arthroplasty (TKA) to establish a patient-specific reference frame.
• Accurate landmark identification is crucial for precise execution of surgical cuts during TKA.

Purpose of the Study:

• To evaluate the accuracy of tibial bone cuts using an image-free computer navigation system in TKA.
• To assess the impact of landmarking errors on the coronal angle of tibial cuts in navigated TKA.

Main Methods:

• Seventy sawbones underwent tibial cuts using a computer navigation system.
• Landmarks were consistently marked, with variations introduced at the tibial mechanical entry point (0, ±5, ±10, ±15 mm).
• The coronal angle of tibial cuts was measured directly and compared with the navigation system's output.

Main Results:

• Significant deviations in the coronal angle of tibial cuts were observed across different landmarking error groups.
• The accuracy of the tibial cut angle was compromised by medial and lateral offsets in landmark placement.
• The navigation system failed to identify or correct for the introduced landmarking errors.

Conclusions:

• Landmarking inaccuracies during navigated TKA can result in imprecise tibial bone cuts.
• The evaluated computer navigation system lacks iterative software methods to detect and rectify landmarking errors.
• Improvements in landmark verification are necessary for reliable navigated TKA outcomes.