Are acetabular component alignment guides for total hip arthroplasty accurate?

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Surgical Navigation

Background:

• Acetabular component orientation is crucial for successful total hip arthroplasty (THA).
• While navigation systems exist, traditional alignment guides remain prevalent in many hospitals.
• The accuracy of these widely used alignment guides has not been systematically assessed.

Purpose of the Study:

• To evaluate the accuracy of commonly used acetabular component alignment guides in THA.
• To quantify discrepancies between indicated and manufacturer-stated angles for anteversion and inclination.

Main Methods:

• Fifteen different types of acetabular alignment guides were examined.
• Actual indicated angles were compared against the angles specified by manufacturers for each guide.

Main Results:

• Significant discrepancies were found between indicated and stated angles in all tested alignment guides.
• On average, guides led to a 6-degree decrease in anteversion (up to 12 degrees) and a 2-degree increase in inclination (up to 4 degrees).
• These inaccuracies suggest inherent flaws in the design or calibration of modern alignment guides.

Conclusions:

• Current acetabular component alignment guides may introduce systematic errors in THA surgery.
• The observed deviations in anteversion and inclination could be a contributing factor to suboptimal clinical results.
• Re-evaluation and potential redesign of alignment guides are warranted to improve THA component accuracy.