🔍 Key Findings
- Dorsoventral radiographs artificially increase Norberg angle values by 3.2–5.8% and should be excluded.
- Lateral pelvic tilt >2° causes asymmetric changes in Norberg angle; >3° results in significant side-specific changes.
- Cranioventral-to-caudodorsal tilt >10° results in obvious radiographic tilt, but changes Norberg angle by only ~2%.
- Tilted but subjectively acceptable images have minor impact and may still be usable for screening.
- Norberg angle readings differed consistently between left/right hips — possibly due to operator handedness.
