The natural history of foot pressure abnormalities in neuropathic diabetic subjects

The pressures under the feet of 39 subjects with diabetic neuropathy were initially assessed during walking using an optical pedobarograph. The upper limit of normality for pressure readings in non-diabetic subjects had previously been established as 10 kg/sq.cm. These subjects were then followed for a mean period of 3 years after which foot pressure studies were repeated. 39 feet had abnormal results when initially studied, compared with 33 at the follow-up study (p = NS). However, changes in the distribution of pressure under the metatarsal heads were seen in 13 feet, while 20 feet showed changes in abnormal pressures under the same site. Recurrent metatarsal ulcers occurred in 6 feet during the study, with 5 occurring at documented sites of high pressure. It is concluded that important changes in the distribution and level of pressures under diabetic neuropathic feet occur during a relatively short time. As it has previously been demonstrated that increased foot pressures are associated with foot ulceration, it is important for the orthotist to re-assess the feet regularly to establish whether significant changes in pressure distribution that might warrant new insoles or footwear have occurred.