Magnetic Resonance Arthrography and the Prevalence of Acetabular Labral Tears in Patients 50 Years of Age and Older: Is It Really Indicated?

OBJECTIVES: Arthroscopy for acetabular labral tears has minimal impact on pain and function in patients older than 50 years of age in the setting of concomitant osteoarthritis. Despite this, many physicians continue to seek diagnoses of labral tears in older arthritic patients with magnetic resonance arthrography. The inefficacy of surgical management and the suggested high prevalence of this condition in both symptomatic and asymptomatic patients call into question the utility of diagnosis through an invasive and expensive imaging modality. The purpose of this study is to assess the frequency of acetabular labral tears in patients aged 50 years and older with hip pain and to correlate the likelihood of a labral tear with the severity of osteoarthritis as visualized on conventional radiograph. METHODS: From 2004-2013, 208 patients aged 50 years and older who underwent hip MR arthrogram and hip radiographs within a 12-month period were identified. Age, gender, grade and location of labral tear, hip alpha angle, hip Tönnis grade, and hip joint space width were documented for each patient. Labral tears and alpha angle were identified and measured on MR arthrogram. Tönnis grade and joint space width were measured on hip radiographs by a musculoskeletal radiologist. RESULTS: On MR arthrography, labral pathology was identified in 93% of patients (73.1% labral tearing, 20.2% labral fraying or degeneration). In patients with moderate to severe osteoarthritis (Tönnis grade 2-3), 100% had labral pathology (73.1% labral tearing, 26.9% labral fraying or degeneration). Similarly, in patients with joint space width ≤ 2mm, 100% had labral pathology (81.2% labral tearing, 18.8% labral fraying or degeneration). There were no statistically significant correlations between labral tear grade and Tönnis grade or joint space width. CONCLUSION: Given the high frequency of tears, as well as the questionable efficacy of arthroscopic surgical intervention in these patients, only good surgical candidates with chronic hip pain and minimal evidence of osteoarthritis (joint space width > 2mm, Tönnis grade 0-1) on initial radiographic evaluation should be considered for magnetic resonance arthrography.