Preliminary study of image findings of femoroacetabular impingement

Objective: To assess the image findings of femoroacetabular impingement (FAI). Methods: Image findings of 9 patients with surgically proved femoroacetabular impingement were retrospectively reviewed for characteristic image findings of FAI. All 9 patients underwent X-ray examinations and MRI of affected hip, and 1 patient underwent MR arthrography (MRA) additionally. Results: X-ray examinations of all 9 patients showed bump at femoral head-neck junction or overcoverage of the acetabular. MRI showed various degrees of injury of anterosuperior labrum in all 9 patients. The injuries were stage Ⅰ A in 2 cases, stage Ⅰ B in 3, stage Ⅱ A in 2, and stage Ⅱ B in 2. MRA of the case showed tears of anterosuperior labrum, with contrast media entering into the teared labrum. There were sclerosis and cystic degeneration of subchondral bone of femoral head in 2 cases, and these findings were confirmed as cartilage delamination by surgery. Conclusions: MRI can display the injures of labrum and articular cartilage, which is helpful to the early diagnosis of' FAI. (authors)