Michael Andrew Mahlon DO, Presenter: Nothing to Disclose

Stephanie Adriane Bernard MD, Abstract Co-Author: Nothing to Disclose

Eric A. Walker MD, Abstract Co-Author: Research Consultant, Medical Metrics, Inc

Pamela L. Brian MD, Abstract Co-Author: Nothing to Disclose

Jonelle Marie Petscavage MD, MPH, Abstract Co-Author: Consultant, Medical Metrics, Inc

Donald Joel Flemming MD, Abstract Co-Author: Royalties, Reed Elsevier

Timothy J. Mosher MD, Abstract Co-Author: Consultant, Kensey Nash Corporation Consultant, Medical Metrics, Inc Consultant, eImage Stockholder, Johnson & Johnson

Normal variant sulci are well described in the posterior inferior and anterior inferior hip labrum. Hip MR arthrography (MRA) 3T imaging demonstrates linear signal in the posterior superior (PS) hip chondrolabral junction, not previously recognized as a normal variant. This study evaluates whether this PS labral signal abnormality represents a normal variant or labral tear.

A retrospective review of 200 consecutive hip MRAs performed between 01/2008 and 08/2011. Consensus interpretation of labral and cartilage abnormalities was performed by 3 musculoskeletal radiologists. Labral abnormalities were divided into anterior superior (AS), posterior superior (PS), anterior inferior (AI) and posterior inferior (PI) quadrants. Arthroscopic reports were correlated with the imaging findings when available (20%). Patient demographics, symptomatology at time of imaging, response to intraarticular anesthetic and clinical diagnoses at follow up were recorded.

10 MRA were excluded. Of the 190 MRAs reviewed, 131 patients were female (59%) / 59 male (31%); patient ages ranged from 14-65 years (mean 36.4 yrs). MRAs demonstrated AS labral tears in 134 (70.5%); PS labral abnormalities in 69 (36.3%), AI recesses in 20 (10.5%) and PI recesses in 46 (24.2%). Arthroscopic correlation was available for 29 of the AS findings with concordance of tear diagnosis in 28 (97%). Arthroscopic correlation of PS labral abnormalities was available in 17 of the 69 (22%) with 8 (47%) diagnosed as tears and 9 (53%) as normal at surgery. MRA findings interpreted as AI and PI recesses were confirmed as arthroscopically normal in 1 and 8 patients, respectively.

Posterior superior labral abnormalities were seen in more than 1/3rd of the hip labra imaged with MRA, much more frequent than previously reported for western patients. Signal abnormalities in the posterior superior chondrolabral junction are much less accurate at predicting labral tear at surgery than similar findings in the anterior superior labrum tear, the positive predictive value of only 47%.

Posterior superior hip labral signal abnormalities appear to represent an anatomic variant in many patients instead of a labral tear and should be interpreted with caution.

Mahlon, M, Bernard, S, Walker, E, Brian, P, Petscavage, J, Flemming, D, Mosher, T, Contrast Extension into the Posterior Superior Chondrolabral Junction of the Hip on MR Arthrography: Tear or Normal Variant .  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12028883.html