title: Involvement of different risk factors in clinically severe large joint osteoarthritis according to the presence of hand interphalangeal nodes.
abstract: OBJECTIVE
  To quantify the differences in risk factors influencing total hip replacement (THR) and total knee replacement (TKR) based on the presence versus absence of multiple interphalangeal nodes in 2 or more rays of the fingers of each hand in patients with large joint osteoarthritis (OA).
  
  
  METHODS
  A group of 3,800 patients with large joint OA who underwent total joint replacement (1,201 of whom had the nodal phenotype) and 1,906 control subjects from 2 case-control studies and a population-based cohort in the UK were studied. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated for the risk of total joint replacement in association with age, sex, body mass index (BMI), height, and prevalence of the T allele in the GDF5 rs143383 polymorphism. ORs for total joint replacement were compared between cases of nodal OA and cases of non-nodal OA and between patients who underwent TKR and those who underwent THR.
  
  
  RESULTS
  Age, sex, and BMI had significantly higher ORs for an association with total joint replacement in nodal OA cases than in non-nodal OA cases. The GDF5 polymorphism was significantly associated with THR in cases of nodal OA, but not in cases of non-nodal OA, and increased height was a risk factor for THR in non-nodal OA cases only. Female sex was a protective risk factor for TKR in non-nodal OA cases (OR 0.60, 95% CI 0.52-0.70) but was predisposing for TKR in the nodal form of OA (OR 1.83, 95% CI 1.49-2.26). The nodal phenotype was associated with a significantly higher risk of undergoing both THR and TKR (OR 1.46, 95% CI 1.09-1.94) and also a significantly higher risk of bilateral TKR (OR 1.70, 95% CI 1.37-2.11), but, paradoxically, was associated with a lower risk of bilateral THR (OR 0.72, 95% CI 0.56-0.91).
  
  
  CONCLUSIONS
  Nodal and non-nodal forms of large joint OA have significantly different risk factors and outcomes, indicating a different etiology for the 2 forms of OA. With regard to the likelihood of undergoing THR, this appears to be, at least in part, genetically determined.
authors.affiliation: Department of Twin Research and Genetic Epidemiology, King's College London and St. Thomas' Hospital, London, UK. ana.valdes@kcl.ac.uk
authors.forename: Ana M
authors.initials: AM
authors.lastname: Valdes
authors.forename: Daniel
authors.initials: D
authors.lastname: McWilliams
authors.forename: Nigel K
authors.initials: NK
authors.lastname: Arden
authors.forename: Sally A
authors.initials: SA
authors.lastname: Doherty
authors.forename: Margaret
authors.initials: M
authors.lastname: Wheeler
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Muir
authors.forename: Weiya
authors.initials: W
authors.lastname: Zhang
authors.forename: Cyrus
authors.initials: C
authors.lastname: Cooper
authors.forename: Rose A
authors.initials: RA
authors.lastname: Maciewicz
authors.forename: Michael
authors.initials: M
authors.lastname: Doherty
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D019645:Arthroplasty, Replacement, Knee; D015992:Body Mass Index; D016022:Case-Control Studies; D005260:Female; D005384:Finger Joint / Q000473:pathology*; D055428:Growth Differentiation Factor 5 / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000235:genetics / Q000473:pathology; D016017:Odds Ratio; D009999:Ossification, Heterotopic / Q000150:complications / Q000235:genetics / Q000473:pathology*; D015207:Osteoarthritis, Hip / Q000209:etiology / Q000235:genetics / Q000473:pathology*; D020370:Osteoarthritis, Knee / Q000209:etiology / Q000235:genetics / Q000473:pathology*; D011110:Polymorphism, Genetic; D012307:Risk Factors; D012737:Sex Factors
chemical_list: C525893:GDF5 protein, human; D055428:Growth Differentiation Factor 5