Objective. The objective of this study was to evaluate the effects of continuous leg traction on contrast-enhanced MR imaging of the
hip joint and to determine whether MR imaging under these conditions is useful for demonstrating acetabular labral tears.
Design and patients. Nineteen hips underwent MR imaging with a T1-weighted spin-echo sequence, followed by MR imaging under continuous leg traction
after intravenous injection of gadolinium-DTPA. Joint fluid enhancement and labral contour detection were evaluated. Eleven
hips had labral tears shown by conventional arthrography, arthroscopy and macroscopic surgical findings. Assessment of labral
tears by MR imaging was correlated with the diagnosis based on these standard techniques.
Results and conclusions. Joint fluid enhancement was obtained in all hips at 30 min after injection. Superior and inferior labral surfaces were completely
delineated in 1 hip on the unenhanced MR images, and in 7 and 13 hips, respectively, on the enhanced images under traction.
The enhanced images under traction depicted 9 of the 11 labral tears. Comparison between the unenhanced image and the enhanced
image under traction avoided mistaking undercutting of the labrum for a tear in 4 hips. Contrast-enhanced MR imaging under
traction was valuable for detecting labral tears non-invasively and without radiation. Follow-up examinations using this method
in patients with acetabular dysplasia can help to clarify the natural course of labral disorders and enable better treatment
planning.
Key words Acetabular labrum - Magnetic resonance imaging - hip - Gadolinium - Traction