title: Responsiveness and validity of the SF-36, Ankle Osteoarthritis Scale, AOFAS Ankle Hindfoot Score, and Foot Function Index in end stage ankle arthritis.
abstract: BACKGROUND
  We examined four commonly used scores, the SF-36, the Ankle Osteoarthritis Scale (AOS), the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle Hindfoot Score, and the Foot Function Index (FFI) to determine their responsiveness and validity.
  
  
  METHODS
  Patients with end stage ankle arthritis were recruited into a prospective multicenter cohort study and baseline and one year outcome scores were compared. The Standardized Response Mean and Effect Size for the AOS, AOFAS, and FFI were calculated and the three region- or disease-specific scores were compared with the SF-36 to determine their criterion validity.
  
  
  RESULTS
  All four scores showed acceptable responsiveness, and when using the validated SF-36 as the standard the three region or disease specific scores all showed similar criterion validity.
  
  
  CONCLUSIONS
  All four scores are responsive and can be considered for use in this population. The objective component of the AOFAS Ankle Hindfoot Score may make it harder to perform than the other three scores which have subjective components only, and as yet its objective component has not been shown to demonstrate reliability. We recommend use of a purely subjective score such as the Ankle Osteoarthritis Scale or Foot Function Index as the region- or disease-specific score of choice in this population. As the SF-36 shows acceptable responsiveness, using it alone could also be considered.
authors.affiliation: Department of Orthopaedics, Glasgow Royal Infirmary., Glasgow, UK. janemadeley@yahoo.co.uk
authors.forename: N Jane
authors.initials: NJ
authors.lastname: Madeley
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Wing
authors.forename: Claire
authors.initials: C
authors.lastname: Topliss
authors.forename: Murray J
authors.initials: MJ
authors.lastname: Penner
authors.forename: Mark A
authors.initials: MA
authors.lastname: Glazebrook
authors.forename: Alastair Se
authors.initials: AS
authors.lastname: Younger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D004185:Disability Evaluation; D005260:Female; D033023:Foot Joints / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000503:physiopathology* / Q000628:therapy; D017063:Outcome Assessment, Health Care / Q000379:methods*; D010147:Pain Measurement; D011446:Prospective Studies; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology; D018709:Statistics, Nonparametric; D016896:Treatment Outcome