Hip MRI: Prevalence of Articular Cartilage Defects and Labral Tears in Asymptomatic Volunteers. A Comparison with a Matched Population of Patients with Femoroacetabular Impingement

Purpose: To prospectively compare defects of the articular cartilage and labrum in asymptomatic volunteers and in patients with femoroacetabular impingement (FAI) matched for age and gender.

Materials And Methods: This cross-sectional study was institutional review board approved. A total of 63 asymptomatic volunteers and 63 patients with symptomatic FAI between 20 and 50 years underwent 1.5 Tesla MRI (coronal T1-weighted, coronal intermediate-weighted fat saturated, transverse oblique true fast imaging with steady-state precession [FISP], sagittal dual echo steady state [DESS] sequence). Two radiologists independently assessed defects of the cartilage and labrum at six positions. Statistics included Mann-Whitney U-test and Spearman's rho.

Results: A defect of the articular cartilage and/or labrum was present on average in 57% of asymptomatic volunteers, compared with 80% of symptomatic patients (P ≤ 0.028). A total of 14% of volunteers had acetabular cartilage defects, and 6% had femoral cartilage defects, compared with 47% and 30% in symptomatic patients (P ≤ 0.001 and P ≤ 0.003), respectively. Labrum defects were seen in 44% of volunteers versus 61% of patients (P ≤ 0.12). Both cartilage and labral defects were more commonly encountered in male volunteers than in female volunteers, with the largest difference seen for the acetabular cartilage (P ≤ 0.02). In all groups, the majority of cartilage and labrum defects were encountered in the anterosuperior, superior, and posterosuperior position.

Conclusion: A substantial number of asymptomatic volunteers had labral tears, defects of the acetabular cartilage, and to a lesser degree, defects of the femoral cartilage; our data demonstrate that not all cartilage and labral defects of the hip joint are symptomatic and that a similar predilection for location of defects is found in volunteers and FAI patients.

Level Of Evidence: 2 Technical Efficacy: Stage 3 J. MAGN. RESON. IMAGING 2017;46:440-451.