title: The relationship between foot and ankle symptoms and risk of developing knee osteoarthritis: data from the osteoarthritis initiative.
abstract: To investigate whether foot and/or ankle symptoms increase the risk of developing (1) knee symptoms and (2) symptomatic radiographic knee osteoarthritis (OA).
  
  
  
  1020 Osteoarthritis Initiative (OAI) participants who were at-risk of knee OA, but were without knee symptoms or radiographic knee OA, were investigated. Participants indicated the presence and laterality of foot/ankle symptoms at baseline. The main outcome was development of knee symptoms (pain, aching or stiffness in and around the knee on most days of the month for at least 1 month in the past year). A secondary outcome was development of symptomatic radiographic knee OA (symptoms plus Kellgren and Lawrence [KL] grade ≥2), over the subsequent 4 years. Associations between foot/ankle symptoms and study outcomes were assessed by logistic regression models.
  
  
  
  Foot/ankle symptoms in either or both feet significantly increased the odds of developing knee symptoms (adjusted odds ratio (OR) 1.55, 95% confidence interval (CI) 1.10 to 2.19), and developing symptomatic radiographic knee OA (adjusted OR 3.28, 95% CI 1.69 to 6.37). Based on laterality, contralateral foot/ankle symptoms were associated with developing both knee symptoms (adjusted OR 1.68, 95% CI 1.05 to 2.68) and symptomatic radiographic knee OA (adjusted OR 3.08, 95% CI 1.06 to 8.98), whilst bilateral foot/ankle symptoms were associated with developing symptomatic radiographic knee OA (adjusted OR 4.02, 95% CI 1.76 to 9.17).
  
  
  
  In individuals at-risk of knee OA, the presence of contralateral foot/ankle symptoms in particular increases risk of developing both knee symptoms and symptomatic radiographic knee OA.
authors.affiliation: Centre for Health, Exercise and Sports Medicine, The University of Melbourne, Melbourne, Australia. Electronic address: kade.paterson@unimelb.edu.au.
authors.forename: K L
authors.initials: KL
authors.lastname: Paterson
authors.affiliation: Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia. Electronic address: jessica.kasza@monash.edu.
authors.forename: J
authors.initials: J
authors.lastname: Kasza
authors.affiliation: Institute of Bone and Joint Research, Kolling Institute, University of Sydney, Sydney, Australia; Rheumatology Department, Royal North Shore Hospital Australia, Sydney, Australia. Electronic address: david.hunter@sydney.edu.au.
authors.forename: D J
authors.initials: DJ
authors.lastname: Hunter
authors.affiliation: Centre for Health, Exercise and Sports Medicine, The University of Melbourne, Melbourne, Australia. Electronic address: ranash@unimelb.edu.au.
authors.forename: R S
authors.initials: RS
authors.lastname: Hinman
authors.affiliation: School of Allied Health, La Trobe University, Melbourne, Australia. Electronic address: H.Menz@latrobe.edu.au.
authors.forename: H B
authors.initials: HB
authors.lastname: Menz
authors.affiliation: Arthritis Research UK Primary Care Centre, Keele University, Keele, United Kingdom. Electronic address: g.m.peat@keele.ac.uk.
authors.forename: G
authors.initials: G
authors.lastname: Peat
authors.affiliation: Centre for Health, Exercise and Sports Medicine, The University of Melbourne, Melbourne, Australia. Electronic address: k.bennell@unimelb.edu.au.
authors.forename: K L
authors.initials: KL
authors.lastname: Bennell
mesh_terms: D000367:Age Factors; D000368:Aged; D000842:Ankle / Q000503:physiopathology*; D015331:Cohort Studies; D016001:Confidence Intervals; D016208:Databases, Factual; D018450:Disease Progression; D005260:Female; D005528:Foot / Q000503:physiopathology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010003:Osteoarthritis / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000209:etiology; D011379:Prognosis; D011859:Radiography / Q000379:methods; D018570:Risk Assessment; D012737:Sex Factors
keywords: Arthritis; Epidemiology; Knee osteoarthritis; Osteoarthritis