Validating a Modified Circle Theorem Method for the Measurement of Acetabular Cup Anteversion on Plain Radiography with Intra-Operative Data from Robotic Assisted Total Hip Arthroplasty

Validating a Modified Circle Theorem Method for the Measurement of Acetabular Cup Anteversion on Plain Radiography with Intra-Operative Data from Robotic Assisted Total Hip Arthroplasty

Authors

Amirouche F, Solitro GF, Chandrasekaran S, Domb BG, Gonzalez MH.

Purpose

To validate a modified circle theorem method for measuring acetabular cup anteversion on plain X-rays, using intraoperative robotic data as the gold standard.

Methods

• 80 total hip arthroplasties with intraoperative robotic measurements of cup anteversion.
• Compared robotic anteversion data to measurements on anteroposterior radiographs using the modified circle theorem.

Key Findings

• Mean robotic anteversion: 21.2° ± 2.0°, radiographic anteversion: 19.9° ± 3.4°.
• 97.5% of radiographic measurements were within 30% relative error of robotic data.
• Strong correlation between radiographic and robotic measurements (Pearson r = 0.9422).

Conclusion

The modified circle theorem method is a valid and reliable technique to measure acetabular cup anteversion on plain radiographs.

What This Means for Patients

Surgeons can accurately measure hip implant positioning using standard X-rays, which can help ensure optimal implant placement and function.

DOI: 10.1016/j.arth.2015.07.042