title: Radiographic hand osteoarthritis: patterns and associations with hand pain and function in a community-dwelling sample.
abstract: OBJECTIVE
  Patterns of radiographic osteoarthritis (ROA) of the hand are often examined by row, with the four joints of the thumb studied inconsistently. The objectives of this study were to determine relationships of ROA at different hand joints, use the findings to define radiographic sub-groups and investigate their associations with pain and function.
  
  
  METHODS
  Sixteen joints in each hand were scored for the presence of ROA in a community-dwelling cohort of adults, 50-years-and-over, with self-reported hand pain or problems. Principal components analysis (PCA) with varimax rotation was used to study patterns of ROA in the hand joints and identify distinct sub-groups. Differences in pain and function between these sub-groups were assessed using Australian/Canadian Osteoarthritis Index (AUSCAN), Grip Ability Test (GAT) and grip and pinch strength.
  
  
  RESULTS
  PCA was undertaken on data from 592 participants and identified four components: distal interphalangeal joints (DIPs), proximal interphalangeal joints (PIPs), metacarpophalangeal joints (MCPs), thumb joints. However, the left thumb interphalangeal (IP) joint cross-loaded with the PIP and thumb groups. On this basis, participants were categorised into four radiographic sub-groups: no osteoarthritis (OA), finger only OA, thumb only OA and combined thumb and finger OA. Statistically significant differences were found between the sub-groups for AUSCAN function, and in women alone for grip and pinch strength. Participants with combined thumb and finger OA had the worst scores.
  
  
  CONCLUSIONS
  Individual thumb joints can be clustered together as a joint group in ROA. Four radiographic sub-groups of hand OA can be distinguished. Pain and functional difficulties were highest in participants with both thumb and finger OA.
authors.affiliation: Arthritis Research Campaign National Primary Care Centre, Primary Care Sciences, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom. m.marshall@cphc.keele.ac.uk
authors.forename: M
authors.initials: M
authors.lastname: Marshall
authors.forename: D
authors.initials: D
authors.lastname: van der Windt
authors.forename: E
authors.initials: E
authors.lastname: Nicholls
authors.forename: H
authors.initials: H
authors.lastname: Myers
authors.forename: E
authors.initials: E
authors.lastname: Hay
authors.forename: K
authors.initials: K
authors.lastname: Dziedzic
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005384:Finger Joint / Q000000981:diagnostic imaging / Q000502:physiology*; D006225:Hand / Q000000981:diagnostic imaging / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D010147:Pain Measurement; D011859:Radiography; D012720:Severity of Illness Index; D013933:Thumb / Q000000981:diagnostic imaging / Q000502:physiology*