Foot ulcer recurrence, plantar pressure and footwear adherence in people with diabetes and Charcot midfoot deformity: A cohort analysis.

AIMS: To investigate people with Charcot midfoot deformity with regard to plantar pressure, footwear adherence and plantar foot ulcer recurrence. METHODS: Twenty people with diabetes, Charcot midfoot deformity, plantar foot ulcer history and custom-made footwear were assessed with regard to barefoot and in-shoe plantar pressures during walking, footwear adherence (% of daily steps over 7-day period) and plantar foot ulcer recurrence over 18 months. In a cohort design, they were compared to 118 people without Charcot foot (non-Charcot foot group) with custom-made footwear and similar ulcer risk factors. RESULTS: Median (interquartile range) barefoot midfoot peak pressures were significantly higher in the Charcot foot group than in the non-Charcot foot group [756 (260-1267) vs 146 (100-208) kPa; P<0.001]. In-shoe midfoot peak pressures were not significantly higher in the Charcot foot group [median (interquartile range) 152 (104-201) vs 119 (94-160) kPa] and significantly lower for all other foot regions. Participants in the Charcot foot group were significantly more adherent, especially at home, than participants in the non-Charcot foot group [median (interquartile range) 94.4 (85.4-95.0)% vs. 64.3 (25.4-85.7)%; P=0.001]. Ulcers recurred in 40% of the Charcot foot group and in 47% of the non-Charcot foot group (P=0.63); midfoot ulcers recurred significantly more in the Charcot foot group (4/8) than in the non-Charcot foot group (1/55; P=0.001). CONCLUSIONS: Effective offloading and very high footwear adherence were found in people with diabetes and Charcot midfoot deformity. While this may help protect against plantar foot ulcer recurrence, a large proportion of such people still experience ulcer recurrence. Further improvements in adherence and custom-made footwear design may be required to improve clinical outcome.

Offloading effect of therapeutic footwear in patients with diabetic neuropathy at high risk for plantar foot ulceration.

AIMS: Custom-made therapeutic footwear is often prescribed to patients with diabetic neuropathy, foot deformity and a healed plantar foot ulcer. Offloading these feet is important to prevent ulcer recurrence. The aim was to evaluate the offloading effect of custom-made footwear in these patients. METHODS: In 171 patients with diabetic neuropathy (336 feet) with foot deformity and a recently healed plantar foot ulcer, plantar pressures walking barefoot and inside new custom-made footwear were measured. At the previous ulcer location and at locations of highest barefoot pressure attributable to the deformity, in-shoe pressures were compared with non-deformed feet. The footwear was considered effective in offloading when in-shoe peak pressure at these locations was < 200 kPa. RESULTS: Mean in-shoe peak pressures ranged between 211 and 308 kPa in feet with forefoot deformity (vs. 191-222 kPa in non-deformed feet) and between 140 and 187 kPa in feet with midfoot deformity (vs. 112 kPa in non-deformed feet). Offloading was effective in 61% of all feet with deformity, 81% of feet with midfoot deformity, 44% of feet with forefoot deformity and 62% of previous ulcer locations. Inter-subject variability in measured in-shoe plantar pressure was large. CONCLUSIONS: Offloading in custom-made footwear is often not sufficiently achieved in high-risk diabetic feet with deformity. Highest offloading success rates were seen at known high-risk locations such as previous ulcer locations and Charcot feet, the lowest success rates in forefoot deformities. Together with the large inter-subject variability in pressure outcomes, this emphasizes the need for evidence-based prescription and evaluation procedures to assure adequate offloading.