Purpose The purpose of this study was to investigate whether acetabular morphology may influence both pathogenesis and prognosis of the acetabular rim lesions and to propose a new system to classify labral tears. Methods We assessed radiographic and arthroscopic findings in 81 patients (40 male and 41 female patients, 86 hips) aged from 16 to 74 years (median, 31 years) who underwent hip arthroscopy. Results Acetabular rim lesions were associated with four different hip morphologies. Eleven (32 ) of 34 patients with severe rim lesions underwent hip arthroplasty for progressive symptoms, whereas no patient with early rim lesion reported significant progression of symptoms. The strategy of treatment was changed in 33 of the patients undergoing arthroscopy before undertaking peri-acetabular osteotomy. Conclusions Hip arthroscopy avoids more invasive procedures in patients with early acetabular rim lesions.