title: Is there an association between pseudoexfoliation syndrome and knee osteoarthritis?
abstract: OBJECTIVE
  The purpose of this study was to investigate whether there is an association between pseudoexfoliation (PEX) syndrome and knee osteoarthritis (OA), and compare to compare patients with PEX and OA to a control group without PEX.
  
  
  METHODS
  This observational case-control study examined 254 subjects: 127 cases with PEX in at least one eye and 127 controls without PEX. A full ophthalmic examination including slit lamp biomicroscopy, gonioscopy, applanation tonometry, pupil dilation, and fundus examination was performed for the diagnosis of PEX. Knee pain was evaluated using a visual analogue scale (VAS). Knee OA was diagnosed according to American College of Rheumatology (ACR) criteria and graded according to the Kellgren and Lawrence (KL) grading scale on radiographic examination.
  
  
  RESULTS
  Of the 254 subjects, 171 (67.3%) had severe OA and 83 (32.7%) mild OA. Of the 171 patients with severe knee OA, 93 (54.4%) had ocular PEX and the remaining 78 (45.6%) had normal ophthalmologic examination results. Both the PEX and the control groups contained 127 patients; the number of patients with moderate-severe OA was significantly (p = 0.032) higher in the PEX group as compared to controls: 93 patients (73.2%) in the PEX group and 78 (61.5%) in the control group. VAS score (p = 0.037) and KL grade (p = 0.024) were significantly higher in the PEX group than in controls. As evidenced by the odds ratios (ORs) pertaining to the severity of OA, age (OR = 1.112; 95% confidence interval, CI: 1.054-1.173) and PEX (OR = 2.044; 95% CI: 1.164-3.584) had a significant influence, but gender did not.
  
  
  CONCLUSIONS
  This study suggests a probable relationship between OA and ocular PEX. Further studies are needed to analyze the molecular basis of this association. Patients with severe knee OA should be informed about the possibility of having PEX and may be referred for ophthalmologic examination.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Bozok University School of Medicine, 66001, Yozgat, Turkey. drmehmetucar@msn.com.
authors.forename: M
authors.initials: M
authors.lastname: Ucar
authors.affiliation: Department of Physical Medicine and Rehabilitation, Yozgat State Hospital, Yozgat, Turkey.
authors.forename: U
authors.initials: U
authors.lastname: Sarp
authors.affiliation: Department of Ophthalmology, Yozgat State Hospital, Yozgat, Turkey.
authors.forename: K
authors.initials: K
authors.lastname: Kirboga
authors.affiliation: Department of Ophthalmology, Bozok University School of Medicine, Yozgat, Turkey.
authors.forename: M
authors.initials: M
authors.lastname: Adam
authors.affiliation: Department of Orthopaedics and Traumatology, Yozgat State Hospital, Yozgat, Turkey.
authors.forename: H O
authors.initials: HO
authors.lastname: Arik
authors.affiliation: Department of Radiology, Yozgat State Hospital, Yozgat, Turkey.
authors.forename: F
authors.initials: F
authors.lastname: Gundogdu
mesh_terms: D017677:Age Distribution; D000368:Aged; D018771:Arthralgia / Q000175:diagnosis* / Q000453:epidemiology*; D015984:Causality; D015897:Comorbidity; D017889:Exfoliation Syndrome / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000453:epidemiology*; D010147:Pain Measurement / Q000706:statistics & numerical data; D015995:Prevalence; D018570:Risk Assessment; D017678:Sex Distribution; D014421:Turkey / Q000453:epidemiology
keywords: Biopsy; Connective tissue; Glaucoma; Kellgren and Lawrence; Visual analogue scale