Procedure: plantar foot pressures were measured with the patient walking barefoot on the F-Scan mat system
Parameters:
(1) rearfoot plantar pressure in kg per square cm (R, rearfoot defined as the posterior third of the foot)
(2) forefoot plantar pressure in kg per square cm (F)
(3) ratio of forefoot to rearfoot plantar pressure ratio (F/P)
(4) maximum plantar peak pressure for the entire foot
In patients with diabetic neuropathic foot both forefoot and rearfoot pressures are increased.
In severe diabetic neuropathy the forefoot pressure is greater than the rearfoot pressure and so the ratio of F/R is increased. These patients were at increased risk for foot ulceration ascribed to increased pressure effect on the soft tissue.
The change in foot pressure in severe diabetic neuropathy appears to related to the development of talipes equinovarus deformity, possibly due to changes in the Achilles tendon (see 20.21).
Risk factors for diabetic foot ulceration in multivariate logistic regression analysis:
(1) peak plantar foot pressure >= 6 kg per square cm
(2) F/R ratio > 2
(3) vibration perception threshold (VPT) >= 25
(4) cutaneous pressure perception threshold (CPPT) >= 5.07
Items 3 and 4 correlate with the severity of the diabetic neuropathy.
