title: Enthesitis and related changes in the knees in seronegative spondyloarthropathies and skin psoriasis: magnetic resonance imaging case-control study.
abstract: OBJECTIVE
  To describe enhanced magnetic resonance imaging (MRI) features and characteristic entheseal changes in the knees in patients with seronegative spondyloarthropathy (SpA).
  
  
  METHODS
  The 56 patients included 30 with psoriatic arthritis, 5 with ankylosing spondylitis, 5 with reactive arthritis, 5 with ulcerative colitis (UC), 5 with Crohn's disease, and another 6 with skin psoriasis. Controls were 20 healthy subjects without knee complaints. MRI was performed in all participants, emphasizing entheseal sites.
  
  
  RESULTS
  Both knees were studied in 45 (80.3%) patients and one knee in 11 (19.6%). MRI showed evidence of bone marrow edema in 13 (23.2%) patients, cartilaginous erosions in 18 (32.1%), and bone erosions in 9 (16.1%). Enthesitis was found in medial collateral ligaments in 18 (32.1%), lateral collateral ligaments in 8 (14.3%), posterior cruciate ligaments in 3 (5.35%), patellar tendon in 18 (32.1%), biceps femoris insertion in 3 (5.35%), medial patellofemoral ligaments (MPFL) in 5 (8.9%), and lateral patellofemoral ligament in 1 patient (1.8%). In the UC and Crohn's patients (n = 10), 2 had bone erosions and 5 had enthesitis. In the skin psoriasis group (n = 6), one had bone marrow edema; enthesitis was detected in 5 at the patellar tendon insertion and in one in the MPFL. Entheseal-related changes were absent in the controls.
  
  
  CONCLUSIONS
  This is the first study showing entheseal-related changes in the knees in patients with inflammatory bowel disease or skin psoriasis without clinical arthritis. Enthesitis of the knee on MRI may be an early finding in SpA.
authors.affiliation: Department of Rheumatology and Rehabilitation, Faculty of Medicine, Cairo University, Cairo 12613, Egypt. yasseremad68@yahoo.com
authors.forename: Yasser
authors.initials: Y
authors.lastname: Emad
authors.forename: Yasser
authors.initials: Y
authors.lastname: Ragab
authors.forename: Iman
authors.initials: I
authors.lastname: Bassyouni
authors.forename: Omar
authors.initials: O
authors.lastname: Moawayh
authors.forename: Magdy
authors.initials: M
authors.lastname: Fawzy
authors.forename: Ahmed
authors.initials: A
authors.lastname: Saad
authors.forename: Alaa
authors.initials: A
authors.lastname: Abou-Zeid
authors.forename: Johannes J
authors.initials: JJ
authors.lastname: Rasker
mesh_terms: D000328:Adult; D015535:Arthritis, Psoriatic / Q000097:blood / Q000150:complications / Q000473:pathology; D016918:Arthritis, Reactive / Q000097:blood / Q000150:complications / Q000473:pathology; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000097:blood / Q000150:complications / Q000473:pathology; D003424:Crohn Disease / Q000097:blood / Q000150:complications / Q000473:pathology; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D011565:Psoriasis / Q000097:blood / Q000150:complications / Q000473:pathology*; D012216:Rheumatic Diseases / Q000097:blood / Q000150:complications / Q000473:pathology*; D025242:Spondylarthropathies / Q000097:blood / Q000150:complications / Q000473:pathology*; D013167:Spondylitis, Ankylosing / Q000097:blood / Q000150:complications / Q000473:pathology