title: Synovial plicae of the hip: evaluation using MR arthrography in patients with hip pain.
abstract: OBJECTIVE
  The appearance and distribution of the intra-articular plicae of the hip have been addressed in few reports in the anatomic and radiological literature. This study aims to determine the prevalence of visible synovial hip plicae using MR arthrography and to measure the association of visible synovial hip plicae with MR arthrographic diagnosis of labral tears, femoroacetabular impingement, and osteoarthritis.
  
  
  METHODS
  Following institutional review board approval, 63 direct MR arthrographic examinations of the hip in 61 patients with a clinical history of hip pain were retrospectively reviewed by two experienced musculoskeletal radiologists in consensus. The following variables were measured using a binary system (0 = absent; 1 = present): labral plica, neck plica, ligamental plica, labral tear, femoroacetabular impingement, and osteoarthritis. The surgical reports and arthroscopic images of 10 patients were reviewed. Statistical analysis was performed using the Fisher's exact test.
  
  
  RESULTS
  In all 63 cases at least one plica was visualized on MR-arthrographic images. Labral, neck, and ligamental plicae were found with a prevalence of 76, 97, and 78%, respectively. There was no statistically significant association between the presence of labral tears, femoroacetabular impingement, and osteoarthritis among patients with visible labral, neck, and ligamental plicae. The prevalence of labral tears, femoroacetabular impingement, and osteoarthritis in our patient population was 79, 28, and 28%, respectively. The presence of intra-articular plicae was the only MR-arthrographic finding in 5 of our 63 symptomatic cases.
  
  
  CONCLUSIONS
  Visible labral, neck, and/or ligamental plicae are highly prevalent on MR-arthrographic images of the hip performed in the setting of hip pain. There was no statistically significant association between the presence of labral tears, femoroacetabular impingement, and osteoarthritis and visible labral, neck, and ligamental plicae.
authors.affiliation: Department of Radiology, NYU Hospital for Joint Diseases, 301 East 17th Street, Sixth Floor, New York, NY 10003, USA. Jenny.Bencardino@nyumc.org
authors.forename: Jenny T
authors.initials: JT
authors.lastname: Bencardino
authors.forename: Ara
authors.initials: A
authors.lastname: Kassarjian
authors.forename: Renata La Rocca
authors.initials: RL
authors.lastname: Vieira
authors.forename: Richard
authors.initials: R
authors.lastname: Schwartz
authors.forename: Jose M
authors.initials: JM
authors.lastname: Mellado
authors.forename: Mininder
authors.initials: M
authors.lastname: Kocher
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology*; D011859:Radiography; D012189:Retrospective Studies; D013583:Synovial Membrane / Q000473:pathology*
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