title: Generalized joint hypermobility is more common in chronic fatigue syndrome than in healthy control subjects.
abstract: OBJECTIVE
  This study aimed at (1) comparing the prevalence of generalized hypermobility in patients with chronic fatigue syndrome (CFS) and healthy volunteers, (2) examining the clinical importance of generalized hypermobility in patients with CFS, and (3) examining whether knee proprioception is associated with hypermobility in patients with CFS.
  
  
  METHODS
  Sixty-eight patients with CFS filled out two self-reported measures (for the assessment of symptom severity and disability), were questioned about muscle and joint pain, and were screened for generalized hypermobility. Afterward, the patients performed a knee repositioning test (assessment of knee proprioception), and it was examined whether or not they fulfilled the criteria for benign joint hypermobility syndrome (BJHS). Sixty-nine age- and sex-matched healthy volunteers were screened for generalized joint hypermobility and performed the same knee repositioning test.
  
  
  RESULTS
  Compared with the healthy volunteers (4.3%, 3/68), significantly more patients with CFS (20.6%, 14/69) fulfilled the criteria for generalized joint hypermobility (Fisher exact test, P < .004). No associations were found between generalized joint hypermobility and the self-reported measures (including pain severity) or knee proprioception (Spearman correlation analysis). Knee proprioception was similar in both groups (Mann-Whitney U = 1961, z = -1.745, P = .81). Forty patients with CFS (58.8%) fulfilled the criteria for BJHS.
  
  
  CONCLUSIONS
  These data indicate that a subgroup of patients with CFS present with generalized joint hypermobility and most patients with of CFS fulfill the diagnostic criteria for BJHS. There appears to be no association between musculoskeletal pain and joint hypermobility in patients with CFS.
authors.affiliation: Department of Human Physiology-Faculty of Physical Education and Physiotherapy Vrije Universiteit Brussel (VUB), Belgium. jo.Nijs@vub.ac.be
authors.forename: Jo
authors.initials: J
authors.lastname: Nijs
authors.forename: Annemie
authors.initials: A
authors.lastname: Aerts
authors.forename: Kenny
authors.initials: K
authors.lastname: De Meirleir
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D015673:Fatigue Syndrome, Chronic / Q000150:complications* / Q000503:physiopathology; D006801:Humans; D007593:Joint Instability / Q000453:epidemiology* / Q000209:etiology*; D007719:Knee Joint / Q000503:physiopathology; D008875:Middle Aged; D015995:Prevalence; D011434:Proprioception