Radiographs Underestimate Lateral Center-Edge Angle and Tönnis Angle Measurements Compared to Computed Tomography Scan in Assessment of Borderline and Frank Acetabular Dysplasia

Radiographs Underestimate Lateral Center-Edge Angle and Tönnis Angle Measurements Compared to Computed Tomography Scan in Assessment of Borderline and Frank Acetabular Dysplasia

Authors

Nerys-Figueroa J, Kahana-Rojkind AH, Parsa A, Walsh EG, Lambers F, Domb BG

Journal

Arthroscopy, 2025

Objective

To evaluate whether standard x-rays underestimate key hip measurements compared to CT scans in diagnosing acetabular dysplasia.

Methodology

A retrospective study of 371 hips, comparing radiographs and CT scans to measure Lateral Center-Edge Angle (LCEA) and Tönnis Angle (TA).

Key Findings

• CT scans showed higher LCEA and TA values compared to x-rays.
• Radiographs overestimated dysplasia using LCEA and underestimated it with TA.
• The differences in measurements impacted clinical interpretation, highlighting the need for accurate assessment.

Conclusion

CT scans offer more accurate measurements for assessing acetabular morphology and should be used alongside radiographs to diagnose borderline or frank dysplasia.

What Does This Mean For Patients

If you're being assessed for hip dysplasia, CT scans might provide more reliable information compared to regular x-rays. This can lead to better treatment decisions, especially for complex cases.