Femoroacetabular Impingement Alpha Angle and Crossover Sign

Calculate the alpha angle from MRI/CT/radiograph for cam-type femoroacetabular impingement (FAI) diagnosis. Alpha angle >55 degrees (Clohisy) or >60 degrees (Netzli) indicates pathological cam morphology. Crossover sign detects pincer morphology.

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Clinical Guidance

BMI is a screening measure of body size, not a direct measure of body fat. The standard WHO categories are underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obese (≥30).

BMI can overestimate body fat in athletes with high muscle mass and underestimate it in older adults with low muscle mass. Interpret it alongside waist circumference and clinical context rather than as a standalone diagnosis.

⚕ Clinical Disclaimer: These calculators are for educational and reference purposes only. Always verify results with qualified clinical judgment and current clinical guidelines. Do not use as a sole basis for medical decisions.
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How It Works

Calculate the alpha angle from MRI/CT/radiograph for cam-type femoroacetabular impingement (FAI) diagnosis. Alpha angle >55 degrees (Clohisy) or >60 degrees (Netzli) indicates pathological cam morphology. Crossover sign detects pincer morphology

Each component has a specific meaning:

  • MRI/CT/radiograph — The mri/ct/radiograph recorded for the scenario being assessed.

Note: Interpret the fai alpha angle result against the thresholds and context described above.

How to Use

Enter the MRI/CT/radiograph for the scenario you are assessing. Calculate the alpha angle from MRI/CT/radiograph for cam-type femoroacetabular impingement (FAI) diagnosis. Alpha angle >55 degrees (Clohisy) or >60 degrees (Netzli) indicates pathological cam morphology. Crossover sign detects pincer morphology. Use the fai alpha angle result to inform your calculation.

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Frequently Asked Questions