MR Arthrography of Acetabular Cartilage Delamination in Femoroacetabular Cam Impingement1

Purpose: To retrospectively assess the frequency and performance of magnetic resonance (MR) arthrography to help diagnose acetabular cartilage delamination in femoroacetabular impingement (FAI). Materials and Methods: Institutional review board approval and informed consent were waived for this retrospective study. Forty-four consecutive patients with FAI of the cam type were included (mean age, 30.7 years; range, 16–49 years), including 30 men (mean age, 30.5 years; range, 16–49 years) and 14 women (mean age, 31.4 years; range, 18–48 years). The inclusion criteria were no previous surgery, surgery within 3 months after MR imaging, and availability of a detailed surgical report with acetabular cartilage findings. MR arthrographic findings were assessed independently by two blinded readers. Findings at surgery served as reference standard. Sensitivity, specificity, accuracy, and κ statistics for interobserver agreement were calculated. Results: At surgery, acetabular cartilage delamination was seen in 23 (...