To report the arthroscopic findings in symptomatic dysplastic hips and to clarify the efficacy of a labral test.

Between July 2001 and Nov 2004, arthroscopy was performed on 37 dysplastic hips. There were 7 males and 30 females and the average age was 38.8 years. The average center-edge angle was 6.54o. Radiographically, 28 hips were prearthritic and 9 hips showed arthritic changes. The arthroscopic findings of the labrum and cartilage and the efficacy of labral test were compared.

Labral lesions were found in 25 cases, and cartilage lesions were found in 16 cases of 28 prearthritic hips. All patients with radiographic evidence of osteoarthritis had both labral and cartilage lesions. Labral lesions were found in 30 out of 33 cases with a positive labral test.

This study identified the pathologic processes of acetabular labrum and cartilage in most cases, even though there was no radiographic evidence of osteoarthritis. Preoperative labral test is a useful physical examination in those suspected of having labral lesions.