Pressure relief and load redistribution by custom-made insoles in diabetic patients with neuropathy and foot deformity.
OBJECTIVE
To study the effects of custom-made insoles on plantar pressures and load redistribution in neuropathic diabetic patients with foot deformity.


METHODS
Cross-sectional.


BACKGROUND
Although custom-made insoles are commonly prescribed to diabetic patients, little quantitative data on their mechanical action exists.


METHODS
Regional in-shoe peak pressures and force-time integrals were measured during walking in the feet of 20 neuropathic diabetic subjects with foot deformity who wore flat or custom-made insoles. Twenty-one feet with elevated risk for ulceration at the first metatarsal head were analysed. Load redistribution resulting from custom-made insoles was assessed using a new load-transfer algorithm.


RESULTS
Custom-made insoles significantly reduced peak pressures and force-time integrals in the heel and first metatarsal head regions; pressures and integrals were significantly increased in the medial midfoot region compared with flat insoles. Custom-made insoles successfully reduced pressures in and integrals at the first metatarsal head in 7/21 feet, were moderately successful in another seven, but failed in the remaining seven. Load transfer was greatest from the lateral heel to the medial midfoot regions.


CONCLUSIONS
Custom-made insoles were more effective than flat insoles in off-loading the first metatarsal head region, but with considerable variability between individuals. Most off-loading occurred in the heel (not a region typically at risk). The load transfer algorithm effectively analyses custom-made-insole action.


CONCLUSIONS
Because similar insole modifications apparently exert different effects in different patients, a comprehensive evaluation of custom designs using in-shoe pressure measurement should ideally be conducted before dispensing insoles to diabetic patients with neuropathy and foot deformity.
Bus
Sicco A
SA
Department of Internal Medicine, Academic Medical Center, University of Amsterdam, 1100 DE Amsterdam, The Netherlands.
Ulbrecht
Jan S
JS
Cavanagh
Peter R
PR
D000465:Algorithms; D017719:Diabetic Foot / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology* / Q000534:rehabilitation*; D003929:Diabetic Neuropathies / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology / Q000534:rehabilitation; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D019544:Equipment Failure Analysis / Q000379:methods*; D005260:Female; D005530:Foot Deformities / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology* / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011312:Pressure; D012775:Shoes; D013314:Stress, Mechanical; D016896:Treatment Outcome; D016474:Weight-Bearing