title: Plantar pressures are higher in cases with diabetic foot ulcers compared to controls despite a longer stance phase duration.
abstract: BACKGROUND
  Current international guidelines advocate achieving at least a 30 % reduction in maximum plantar pressure to reduce the risk of foot ulcers in people with diabetes. However, whether plantar pressures differ in cases with foot ulcers to controls without ulcers is not clear. The aim of this study was to assess if plantar pressures were higher in patients with active plantar diabetic foot ulcers (cases) compared to patients with diabetes without a foot ulcer history (diabetes controls) and people without diabetes or a foot ulcer history (healthy controls).
  
  
  METHODS
  Twenty-one cases with diabetic foot ulcers, 69 diabetes controls and 56 healthy controls were recruited for this case-control study. Plantar pressures at ten sites on both feet and stance phase duration were measured using a pre-established protocol. Primary outcomes were mean peak plantar pressure, pressure-time integral and stance phase duration. Non-parametric analyses were used with Holm's correction to correct for multiple testing. Binary logistic regression models were used to adjust outcomes for age, sex and body mass index. Median differences with 95 % confidence intervals and Cohen's d values (standardised mean difference) were reported for all significant outcomes.
  
  
  RESULTS
  The majority of ulcers were located on the plantar surface of the hallux and toes. When adjusted for age, sex and body mass index, the mean peak plantar pressure and pressure-time integral of toes and the mid-foot were significantly higher in cases compared to diabetes and healthy controls (p < 0.05). The stance phase duration was also significantly higher in cases compared to both control groups (p < 0.05). The main limitations of the study were the small number of cases studied and the inability to adjust analyses for multiple factors.
  
  
  CONCLUSIONS
  This study shows that plantar pressures are higher in cases with active diabetic foot ulcers despite having a longer stance phase duration which would be expected to lower plantar pressure. Whether plantar pressure changes can predict ulcer healing should be the focus of future research. These results highlight the importance of offloading feet during active ulceration in addition to before ulceration.
authors.affiliation: Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, Qld, 4814, Australia. malindu.fernando@my.jcu.edu.au.|Podiatry Service, Townsville Community Health Service , Townsville, QLD, Australia. malindu.fernando@my.jcu.edu.au.|Movement Analysis Laboratory, Sport and Exercise Science, James Cook University, Townsville, Australia. malindu.fernando@my.jcu.edu.au.
authors.forename: Malindu E
authors.initials: ME
authors.lastname: Fernando
authors.affiliation: Sport and Exercise, School of Health and Wellbeing, University of Southern Queensland, Ipswich, QLD, Australia.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Crowther
authors.affiliation: Allied Health Research Collaborative, Metro North Hospital & Health Service, Queensland Health, Brisbane, Australia.|School of Clinical Sciences, Queensland University of Technology, Brisbane, Australia.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Lazzarini
authors.affiliation: Department of Diabetes and Endocrinology, The Townsville Hospital, Townsville, QLD, Australia.
authors.forename: Kunwarjit S
authors.initials: KS
authors.lastname: Sangla
authors.affiliation: School of Clinical Sciences, Queensland University of Technology, Brisbane, Australia.|Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia.
authors.forename: Scott
authors.initials: S
authors.lastname: Wearing
authors.affiliation: Centre for Chronic Disease Prevention, James Cook University, Cairns, QLD, Australia.|Tropical Health Solutions Pty Ltd., Townsville, QLD, Australia.
authors.forename: Petra
authors.initials: P
authors.lastname: Buttner
authors.affiliation: Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, Qld, 4814, Australia.|Department of Vascular and Endovascular Surgery, The Townsville Hospital, Townsville, QLD, Australia.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Golledge
mesh_terms: D000367:Age Factors; D000368:Aged; D001696:Biomechanical Phenomena; D015992:Body Mass Index; D017719:Diabetic Foot / Q000503:physiopathology*; D005260:Female; D005528:Foot / Q000503:physiopathology*; D016523:Foot Ulcer / Q000503:physiopathology / Q000517:prevention & control*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011312:Pressure; D012737:Sex Factors
keywords: Biomechanics; Diabetic foot disease; Foot ulceration; Offloading; Peripheral diabetic neuropathy; Plantar pressure; Plantar ulcers