Identification of Acetabular Labral Pathological Changes in Asymptomatic Volunteers Using Optimized, Noncontrast 1.5-T Magnetic Resonance Imaging

Abstract

Background: Acetabular labral tears as a source of potential hip pain have received a great deal of attention in recent literature. The gold standard for identifying acetabular labral tears is hip arthroscopy, but recent advances in optimized, noncontrast magnetic resonance imaging (MRI) have proven effectiveness in identifying intra-articular hip pathological changes without the invasive nature of hip arthroscopy or gadolinium-enhanced arthrography. There are little data in the literature on imaging results in an asymptomatic population. Purpose: The objective of this study was to use an optimized, noncontrast 1.5-T MRI protocol to identify hip abnormalities, including paralabral cysts, in asymptomatic volunteers. Study Design: Case series (prevalence); Level of evidence, 4. Methods: In this study, 42 hips in asymptomatic patients with an average age of 34 years (range, 27-43 years) were prospectively imaged with optimized, noncontrast 1.5-T MRI scans. Two fellowship-trained musculoskeletal radiologists interpreted the scans at 2 different points in time and commented on the presence of labral abnormalities including paralabral cysts. The results were analyzed for both interobserver and intraobserver reliability. Results: Acetabular paralabral cysts were identified in 11 of 42 (26.2%) and 9 of 42 (21.4%) hips by the 2 respective radiologists, with an interobserver reliability of 90.5% (κ = .74) and intraobserver reliability of 95.2% (κ = .87). In addition, acetabular labral tears were identified in 36 of 42 (85.7%) and 34 of 42 (80.9%) hips, with an interobserver reliability of 90.5% (κ = .70) and intraobserver reliability of 95.2% (κ = .83). Conclusion: Utilizing an optimized, noncontrast 1.5-T MRI protocol, we report the previously undescribed prevalence of acetabular labral pathological abnormalities and paralabral cysts in a young, asymptomatic population. This emphasizes the importance of correlating patient symptoms with history and physical examination when evaluating patients with hip pain and radiographic abnormalities as defined by MRI criteria. These data demonstrate that labral tears can occur without symptoms.