The Measurement of the Lateral Center-Edge Angle Is Underestimated on Radiographs Compared With 3-Dimensional Computed Tomography
Authors
Nerys-Figueroa J, Kahana-Rojkind AH, Parsa A, Maldonado D, Quesada-Jimenez R, Domb BG
Background
Accurate assessment of acetabular coverage is vital in diagnosing hip conditions, often done via radiographic measurement of the lateral center-edge angle (LCEA). However, discrepancies may exist between radiographic and CT-based measurements, potentially influencing diagnosis and treatment.
Methods
A retrospective study of 100 hips from 96 patients compared LCEA measurements from radiographs (using four different anatomical reference points: femoral heads, acetabular teardrops, ischial tuberosities, and floor) to CT-based LCEA at the 12-o'clock position.
Key Findings
- Radiographs consistently underestimated LCEA compared to CT.
- Using femoral heads (FHs) as the reference yielded the most accurate radiographic approximation of CT values (mean difference: 2.3° ± 2.4).
- The smallest variation was between FHs and ITs (1.0° ± 0.8).
- Despite statistical significance, the difference was likely not clinically significant.
Conclusion
Radiographs provide a slightly lower LCEA measurement than CT, with FHs being the most accurate anatomic horizon. While statistically meaningful, these differences may not substantially affect clinical decision-making.
What Does This Mean For Patients
Standard X-rays may slightly underestimate hip socket coverage. Using femoral heads as reference points on radiographs can improve accuracy, although the differences from 3D CT scans are unlikely to change treatment decisions for most patients.