title: Relation of hand enthesophytes with knee enthesopathy: is osteoarthritis related to a systemic enthesopathy?
abstract: OBJECTIVE
  Enthesopathy has been reported as a feature of osteoarthritis (OA) in the distal interphalangeal (DIP) joints. We previously reported that central bone marrow lesions (BML) on magnetic resonance imaging (MRI) scans are associated with OA. In this study, we evaluated whether hand and knee enthesopathy were related.
  
  
  METHODS
  We studied knee and hand radiographs of subjects from the Framingham Osteoarthritis Study. Subjects seen in 2002-2005 had bilateral posteroanterior hand radiographs, weight-bearing knee radiographs, and knee MRI scans. Hand radiographs were read for enthesophytes at the juxtaarticular nonsynovial areas of metacarpophalangeal (MCP), proximal interphalangeal (PIP), and DIP joints, and midshafts of the phalanges. We selected 100 cases of knees with central BML and 100 matched controls. Conditional logistic regression was used to assess associations.
  
  
  RESULTS
  Subjects with enthesophytes of at least 1 score ≥ 2 at DIP, PIP, and/or MCP were not more likely to have central knee BML (OR 0.49, 95% CI 0.17-1.40) than those without enthesophytes. Similarly, having at least 1 score ≥ 2 on the shafts was not significantly associated with having a central knee BML (OR 0.59, 95% CI 0.23-1.51). Adjustment for the presence of diabetes mellitus did not affect these results, but there was an increased prevalence of diabetes in those with hand enthesophytes (OR 3.09, 95% 1.29-7.40, enthesophyte score ≥ 2).
  
  
  CONCLUSIONS
  We found no increase in the prevalence of hand enthesophytes among persons with central knee BML on their knee MRI scans. This provides evidence against a systemic enthesopathic disorder in association with knee OA.
authors.affiliation: Departments of Clinical Epidemiology, Rheumatology and Radiology, Boston University Medical Center, Brigham and Women’s Hospital, Boston, Massachusetts 02118, USA.
authors.forename: Nadia
authors.initials: N
authors.lastname: Gibson
authors.forename: Ali
authors.initials: A
authors.lastname: Guermazi
authors.forename: Margaret
authors.initials: M
authors.lastname: Clancy
authors.forename: Jingbo
authors.initials: J
authors.lastname: Niu
authors.forename: Peter
authors.initials: P
authors.lastname: Grayson
authors.forename: Piran
authors.initials: P
authors.lastname: Aliabadi
authors.forename: Frank
authors.initials: F
authors.lastname: Roemer
authors.forename: David T
authors.initials: DT
authors.lastname: Felson
mesh_terms: D000368:Aged; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D006225:Hand / Q000000981:diagnostic imaging*; D006801:Humans; D007717:Knee / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000000981:diagnostic imaging* / Q000453:epidemiology; D015995:Prevalence; D011859:Radiography; D012216:Rheumatic Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology