Acetabular labral tears: Evaluation with MR arthrography

PURPOSE: To determine the usefulness of magnetic resonance (MR) arthrography in the diagnosis of acetabular labral tears. MATERIALS AND METHODS: MR arthrography of the hip was performed in 10 patients who underwent subsequent surgical evaluation. Eight arthrograms were obtained with intraarticular administration of gadolinium solution and two with intraarticular administration of normal saline. T1-weighted spin-echo (intraarticular gadolinium) or T2'-weighted gradient-echo (intraarticular normal saline) images were obtained in the axial, sagittal, and coronal planes with use of a surface coil. Criteria for labral tears included labral blunting, absence, displacement, intrasubstance contrast material, and contrast material at the acetabular-labral junction. Labra with enlargement, intrasubstance intermediate signal intensity, or irregular margins were interpreted as degenerative. RESULTS: Labral tears were diagnosed in eight hips. Tears included six labra with contrast material that tracked at the acetabular-labral junction, one of which had associated intrasubstance extension. One tear was confined to the labral substance. The other tear exhibited absent labral tissue and an irregular remnant. One degenerative labrum and one normal labrum were identified. All MR arthrographic findings were confirmed at surgery. Extension of one anterosuperior tear into the posterosuperior labrum was not prospectively appreciated. CONCLUSION: In this preliminary study, MR arthrography appears to be a promising imaging modality for accurate diagnosis of acetabular labral tears.