Imageless vs Image-Based Computer Navigation in Total Hip Arthroplasty: An Intracase Comparison Shows Variability...

Area of Science:

• Orthopedic Surgery
• Medical Technology
• Surgical Navigation

Background:

• Computer navigation is increasingly used in total hip arthroplasty (THA).
• Two main modalities exist: imageless (ILCN) and image-based (IBCN).
• Comparing these navigation systems is crucial for accurate component placement.

Purpose of the Study:

• To compare inclination and anteversion measurements between ILCN and IBCN within the same THA case.
• To identify the frequency of discordant measurements between the two navigation modalities.
• To investigate factors associated with measurement discordance.

Main Methods:

• One hundred consecutive THAs utilized both ILCN and IBCN.
• Intraoperative acetabular component inclination and anteversion were recorded for both systems.
• Intracase measurements were compared, and discordant cases (>5° difference) were identified.
• Linear regression analyzed confounding factors for discordance.

Main Results:

• No significant difference in mean inclination or anteversion between ILCN and IBCN.
• Significant discordance observed: 21% for inclination and 32% for anteversion.
• Increased body mass index and prior lumbar spine fusion correlated with anteversion discordance.
• No association found between discordance and dislocation rates.

Conclusions:

• Over 20% of THA cases exhibit discordant measurements between ILCN and IBCN.
• Lumbar spine fusion and elevated body mass index are risk factors for anteversion measurement discordance.
• These findings highlight potential variability in computer-assisted THA outcomes.