[Accuracy measurements of acetabular cup positioning using CT less navigation]

Area of Science:

• Orthopedic Surgery
• Medical Imaging
• Surgical Navigation Technology

Background:

• Standardized methods for evaluating surgical navigation system accuracy are lacking.
• Image-free navigation systems for total hip arthroplasty rely on intraoperative acquisition of anatomic landmarks to define reference planes.
• This landmark acquisition step can introduce significant errors in navigation accuracy.

Purpose of the Study:

• To propose and validate a novel approach for measuring the accuracy of image-free surgical navigation systems in total hip arthroplasty.
• To quantify the influence of clinical application, specifically landmark acquisition, on the overall accuracy of the navigation system.

Main Methods:

• Developed an end-to-end accuracy evaluation model comparing intraoperative navigation system data with postoperative CT measurements.
• Conducted studies on both pelvic bone phantoms and patients to assess system accuracy and quantify landmark acquisition errors.
• Utilized the anterior pelvic plane as a reference system, consistent with common hip navigation practices.

Main Results:

• The proposed model demonstrated accurate cup navigation on pelvic bone phantoms (mean anteversion error 0.9 degrees).
• Clinical studies revealed significant abduction errors (ranging from 2.1 to 16.7 degrees).
• The mean abduction error attributed to anatomic landmark acquisition was 7.2 degrees, highlighting this as a critical error source.

Conclusions:

• The developed accuracy evaluation model provides surgeons with reliable data on navigation system performance.
• The model successfully identified and quantified clinically induced errors, particularly those related to reference system setup.
• Improving the acquisition process for anatomic landmarks is crucial for enhancing the overall accuracy of image-free surgical navigation systems in hip arthroplasty.