Inclusion Criteria: (1) Age 18-50 years old; (2) Diagnosed femoroacetabular impingement syndrome; (3) Conservative treatment ineffective; (4) complete preoperative and postoperative MRI images; -  Exclusion Criteria: (1) bilateral; (2) revision; (3) osteoarthritis; (4) acetabular dysplasia; (5) history of hip and knee joint disease or surgery; (6) femoral head necrosis; (7) sacroiliac joint disease.  -