Accuracy evaluation of a shape-based registration method for a computer navigation system for total knee arthroplasty

Area of Science:

• Orthopedic surgery
• Medical imaging
• Biomedical engineering

Background:

• Accurate registration of pre-operative imaging to intra-operative anatomy is crucial for orthopedic procedures.
• Computed tomography (CT) parameters influence the precision of 3D bone model reconstruction and registration.
• Optimizing CT acquisition and data sampling is essential for balancing accuracy and surgical invasiveness.

Purpose of the Study:

• To evaluate the impact of CT slice thickness, reconstruction pitch, and data sampling on registration accuracy.
• To determine a clinically optimal trade-off between registration accuracy and surgical invasiveness.
• To establish guidelines for CT acquisition and data sampling in orthopedic surgery.

Main Methods:

• Cadaveric femur and tibia CT scans were acquired using varying slice thicknesses and reconstruction pitches.
• Bone surface models were generated from CT data.
• Registration accuracy was assessed by comparing surface models to physical bone measurements using an optical tracking system.

Main Results:

• A combination of 3-mm slice thickness and 1-mm reconstruction pitch, with 30 periarticular sampling points, was identified as optimal.
• This parameter set achieved registration accuracy with minimal bias and root-mean-square errors for both femur and tibia.
• The proposed parameters offer a clinically acceptable balance between accuracy and invasiveness.

Conclusions:

• Optimized CT parameters and data sampling strategies can significantly enhance the accuracy of bone registration in orthopedic surgery.
• The recommended protocol provides a reliable method for intra-operative navigation and planning.
• This research contributes to improving surgical outcomes through precise image-guided interventions.