Plantar Pressure Assessment

Foot ulceration results in substantial morbidity amongst diabetic patients. We have studied prospectively the relationship between high foot pressures and foot ulceration using an optical pedobarograph. A series of 86 diabetic patients, mean age 53.3 (range 17-77) years, mean duration of diabetes 17.1 (range 1-36) years, were followed-up for a mean period of 30 (range 15-34) months. Clinical neuropathy was present in 58 (67%) patients at baseline examination. Mean peak foot pressure was higher at the follow-up compared to baseline (13.5 kg.cm-2 +/- 7.1 SD vs 11.2 +/- 5.4, p less than 0.001) with abnormally high foot pressures (greater than 12.3) being present in 55 patients at follow-up and 43 at the baseline visit (p = NS). Plantar foot ulcers developed in 21 feet of 15 patients (17%), all of whom had abnormally high pressures at baseline; neuropathy was present in 14 patients at baseline. Non-plantar ulcers occurred in 8 (9%) patients. Thus, plantar ulceration occurred in 35% of diabetic patients with high foot pressures but in none of those with normal pressures. We have shown for the first time in a prospective study that high plantar foot pressures in diabetic patients are strongly predictive of subsequent plantar ulceration, especially in the presence of neuropathy.

Treatment of neuropathic plantar ulcers often is directed at reducing excessive, repeated peak plantar pressures (PPP). The purposes of this study were to determine whether instructing a subject to walk using a hip strategy would reduce forefoot PPP and change the kinematics of walking during a single session of testing. Thirteen subjects, 7 with peripheral neuropathy and a history of a recent plantar ulcer, and 6 controls participated. PPPs were measured with an in-shoe pressure monitoring system. Kinematics were measured with a computer-assisted motion analysis system. After data were collected as subjects walked using their normal walking pattern, subjects were instructed to walk using the hip strategy by decreasing their push-off, pulling their leg forward from their hips, decreasing step length, and maintaining their normal walking velocity. Compared with using the normal (ankle) strategy, using the hip strategy showed a significant 27% decrease in forefoot PPP and a 24% increase in heel PPP. Kinematic changes were decreased plantar flexion angular velocity, hip extension range-of motion (ROM), and step length, increased dorsiflexion ROM, and hip flexion ROM, but no change in walking velocity. These findings indicate that a change in walking pattern can result in lower forefoot PPP during a single session. Assuming patients can maintain the alterations in their walking pattern, these adaptations may help to heal plantar ulcers in some patients with peripheral neuropathy.