Table 1 Inclusion and exclusion criteria of patients with FAI

1. Age 18-60 years

2. Clinical diagnosis of symptomatic FAI and/or labral pathology (FADDIR test positive and/or FABER test positive)

3. At least one of the following patterns at the MRI or CT:

3.1. Alpha angle > 55° on radial view

3.2. L-CEA > 40° on coronal view

3.3. A-CEA > 40° on sagittal view

3.4. Cranial acetabular version < 0° on axial view

3.5. Imaging of definite labral tear

4. Planned arthroscopic surgery

1. Age < 18 years or > 60 years

2. Pregnant women, mentally disabled subjects, prisoners, inability to provide informed consensus

3. History of tumor or infection; established diagnosis of rheumatic pathology or clinical and radiographic signs of generalized OA; diabetes, obesity, neurologic disease

4. Arthroscopic surgery performed for reasons other than FAI and/or labral pathology; previous operations (including arthroscopic surgery) at the affected hip

5. Hip contracture (flexion < 90°);

major hip deformities—classic hip dysplasia (L-CEA < 25°); deep acetabular socket (L-CEA > 45°); coxa valga (CDA > 135°); coxa vara (CDA < 120°); global acetabular retroversion (equatorial AV < 10°)