title: Clinical diagnosis of symptomatic midfoot osteoarthritis: cross-sectional findings from the Clinical Assessment Study of the Foot.
abstract: OBJECTIVE
  To derive a multivariable diagnostic model for symptomatic midfoot osteoarthritis (OA).
  
  
  METHODS
  Information on potential risk factors and clinical manifestations of symptomatic midfoot OA was collected using a health survey and standardised clinical examination of a population-based sample of 274 adults aged ≥50 years with midfoot pain. Following univariable analysis, random intercept multi-level logistic regression modelling that accounted for clustered data was used to identify the presence of midfoot OA independently scored on plain radiographs (dorso-plantar and lateral views), and defined as a score of ≥2 for osteophytes or joint space narrowing in at least one of four joints (first and second cuneometatarsal, navicular-first cuneiform and talonavicular joints). Model performance was summarised using the calibration slope and area under the curve (AUC). Internal validation and sensitivity analyses explored model over-fitting and certain assumptions.
  
  
  RESULTS
  Compared to persons with midfoot pain only, symptomatic midfoot OA was associated with measures of static foot posture and range-of-motion at subtalar and ankle joints. Arch Index was the only retained clinical variable in a model containing age, gender and body mass index. The final model was poorly calibrated (calibration slope, 0.64, 95% CI: 0.39, 0.89) and discrimination was fair-to-poor (AUC, 0.64, 95% CI: 0.58, 0.70). Final model sensitivity and specificity were 29.9% (95% CI: 22.7, 38.0) and 87.5% (95% CI: 82.9, 91.3), respectively. Bootstrapping revealed the model to be over-optimistic and performance was not improved using continuous predictors.
  
  
  CONCLUSIONS
  Brief clinical assessments provided only marginal information for identifying the presence of radiographic midfoot OA among community-dwelling persons with midfoot pain.
authors.affiliation: Arthritis Research UK Primary Care Centre, Research Institute for Primary Care and Health Sciences, Keele University, Keele, Staffordshire, ST5 5BG, United Kingdom. Electronic address: m.thomas@keele.ac.uk.
authors.forename: M J
authors.initials: MJ
authors.lastname: Thomas
authors.affiliation: Arthritis Research UK Primary Care Centre, Research Institute for Primary Care and Health Sciences, Keele University, Keele, Staffordshire, ST5 5BG, United Kingdom. Electronic address: e.roddy@keele.ac.uk.
authors.forename: E
authors.initials: E
authors.lastname: Roddy
authors.affiliation: Arthritis Research UK Primary Care Centre, Research Institute for Primary Care and Health Sciences, Keele University, Keele, Staffordshire, ST5 5BG, United Kingdom. Electronic address: t.rathod@keele.ac.uk.
authors.forename: T
authors.initials: T
authors.lastname: Rathod
authors.affiliation: Arthritis Research UK Primary Care Centre, Research Institute for Primary Care and Health Sciences, Keele University, Keele, Staffordshire, ST5 5BG, United Kingdom. Electronic address: m.marshall@keele.ac.uk.
authors.forename: M
authors.initials: M
authors.lastname: Marshall
authors.affiliation: Musculoskeletal Research Unit, School of Clinical Sciences, University of Bristol, United Kingdom. Electronic address: a.j.moore@bristol.ac.uk.
authors.forename: A
authors.initials: A
authors.lastname: Moore
authors.affiliation: Arthritis Research UK Primary Care Centre, Research Institute for Primary Care and Health Sciences, Keele University, Keele, Staffordshire, ST5 5BG, United Kingdom; Lower Extremity and Gait Studies Program, School of Allied Health, La Trobe University, Bundoora, Victoria, 3086, 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, Research Institute for Primary Care and Health Sciences, Keele University, Keele, Staffordshire, ST5 5BG, United Kingdom. Electronic address: g.m.peat@keele.ac.uk.
authors.forename: G
authors.initials: G
authors.lastname: Peat
mesh_terms: D000368:Aged; D019540:Area Under Curve; D003430:Cross-Sectional Studies; D005260:Female; D033023:Foot Joints / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008683:Metatarsophalangeal Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008875:Middle Aged; D055361:Multilevel Analysis; D010003:Osteoarthritis / Q000175:diagnosis*; D054850:Osteophyte / Q000175:diagnosis*; D010808:Physical Examination; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology; D012680:Sensitivity and Specificity; D013640:Tarsal Joints / Q000000981:diagnostic imaging / Q000503:physiopathology*
keywords: Diagnosis; Midfoot; Osteoarthritis; Pain; Primary care