title: An investigation into the aetiology of flexible flat feet: the role of subtalar joint morphology.
abstract: OBJECTIVE
  There is increasing evidence that flexible flatfoot (FF) can lead to symptoms and impairment in health-related quality of life. As such we undertook an observational study investigating the aetiology of this condition, to help inform management. The hypothesis was that as well as increased body mass index (BMI) and increased flexibility of the lower limb, an absent anterior subtalar articulation would be associated with a flatter foot posture.
  
  
  METHODS
  A total of 84 children aged between eight and 15 years old were prospectively recruited. The BMI for each child was calculated, flexibility was assessed using the lower limb assessment scale (LLAS) and foot posture was quantified using the arch height index (AHI). Each child underwent a sagittal T1-weighted MRI scan of at least one foot.
  
  
  RESULTS
  An absent anterior subtalar articulation (p < 0.001) and increased LLAS (p = 0.001) predicted a low AHI. BMI was not a significant predictive factor (p = 0.566).
  
  
  CONCLUSIONS
  This is the first study to demonstrate the importance of the morphology of the subtalar joint on the underlying foot posture in vivo.
  
  
  CONCLUSIONS
  Flexibility of the lower limb and absence of the anterior facet of the subtalar joint are associated with flexible FF and may influence management of this common condition.
authors.affiliation: University of Oxford, Windmill Road, Oxford, OX3, UK.
authors.forename: A
authors.initials: A
authors.lastname: Kothari
authors.affiliation: Oxford University Hospitals NHS Trust, Churchill Hospital, Old Road, Oxford, OX3 7LE, UK.
authors.forename: S
authors.initials: S
authors.lastname: Bhuva
authors.affiliation: Oxford University Hospitals NHS Trust, Windmill Road, Oxford OX3 7HE, UK.
authors.forename: J
authors.initials: J
authors.lastname: Stebbins
authors.affiliation: University of Oxford, Parks Road, Oxford OX1 3PJ, UK.
authors.forename: A B
authors.initials: AB
authors.lastname: Zavatsky
authors.affiliation: University of Oxford, Windmill Road, Oxford, OX3, UK.
authors.forename: T
authors.initials: T
authors.lastname: Theologis
mesh_terms: D000293:Adolescent; D001174:Arthrodesis / Q000379:methods; D002648:Child; D005260:Female; D005413:Flatfoot / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011187:Posture / Q000502:physiology*; D011446:Prospective Studies; D011788:Quality of Life; D016059:Range of Motion, Articular; D013380:Subtalar Joint / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery
keywords: Pes planovalgus; Subtalar joint; Flat feet; Joint hypermobility