Diabetic foot ulcer incidence in relation to plantar pressure magnitude and measurement location

Abstract

Aims: We prospectively examined the relationship between site-specific peak plantar pressure (PPP) and ulcer risk. Researchers have previously reported associations between diabetic foot ulcer and elevated plantar foot pressure, but the effect of location-specific pressures has not been studied.

Methods: Diabetic subjects (n=591) were enrolled from a single VA hospital. Five measurements of in-shoe plantar pressure were collected using F-Scan. Pressures were measured at 8 areas: heel, lateral midfoot, medial midfoot, first metatarsal, second through fourth metatarsal, fifth metatarsal, hallux, and other toes. The relationship between incident plantar foot ulcer and PPP or pressure-time integral (PTI) was assessed using Cox regression.

Results: During follow-up (2.4years), 47 subjects developed plantar ulcers (10 heel, 12 metatarsal, 19 hallux, 6 other). Overall mean PPP was higher for ulcer subjects (219 vs. 194kPa), but the relationship differed by site (the metatarsals with ulcers had higher pressure, while the opposite was true for the hallux and heel). A statistical analysis was not performed on the means, but hazard ratios from a Cox survival analysis were nonsignificant for PPP across all sites and when adjusted for location. However, when the metatarsals were considered separately, higher baseline PPP was significantly associated with greater ulcer risk; at other sites, this relationship was nonsignificant. Hazard ratios for all PTI data were nonsignificant.

Conclusions: Location must be considered when assessing the relationship between PPP and plantar ulceration.

Keywords: Diabetic foot ulcer; Epidemiology; Hallux; Heel; Metatarsal; Plantar pressure.

Conflict of interest statement

The authors have no conflict of interest.

© 2013.

Figures

Fig. 1

Box plot of mean pressure by plantar measurement location (n = 8880) displaying the minimum, 25th percentile, median, 75th percentile, and maximum values at each location. Grey triangles indicate sites where ulcers developed and the peak pressure for that site in the subject who developed the foot ulcer. (Site abbreviations: Calc, heel; Hal, hallux; Lat.MF, lateral midfoot; Med.MF, medial midfoot; MH1, first metatarsal head; MH2_4, second through fourth metatarsal heads; MH5, fifth metatarsal head; Toe, other toes).