OBJECTIVETo investigate foot biomechanics characteristic of patients with type 2 diabetes mellitus.

METHODSThis study was conducted among 303 patients with type 2 diabetes. The whole foot was divided into 10 regions, namely the first toe (T1); the second to fifth toes (T2-5); the first, second, third, fourth, and fifth metatarsals (M1, M2, M3, M4, and M5, respectively); midfoot (MF), and the heel medial (HM). Foot arch index, foot angle and maximum peak pressure (MPP) of the 10 regions were measured using a Footscan gait system.

RESULTSThe maximum peak pressure of 10 regions decreased in the order of M3>M2>HM>M4>HL>M1>M5>T1>ML>T2-5 for the left foot, and in the order of M3>M2>HM>M4>HL>M1>M5>T1>ML>T2-5 for the right foot. The MPP in M1 region was higher in the right than in the left foot (P<0.05). The MPP in M3, M4, M5, and MF was higher in the left than in the right foot (P<0.05). The percentage of high-risk foot (defined by a total plantar pressure ≥70 N/cm) was 34% on the left and 17.7% on the right. An increased BMI was associated with a significant increase in high-risk foot, but not for the right foot in underweight patients. Foot flat phase was extended and forefoot push-off phase shortened in stance phase in the patients. Compared with the right foot, the left foot showed a significantly increased foot arch index and increased low and high arch rates with a decreased normal arch rate. Total plantar pressure was higher in of the left high arch foot than in normal arch foot. The foot angle was significantly larger on the right than on the left. The bilateral total plantar pressures were significantly greater in male patients (P<0.05) and increased with age but were not associated with the duration of DM, foot angle, or glycosylated hemoglobin level.

CONCLUSIONDiabetic patients have obvious alterations in foot biomechanics with abnormalities of the plantar pressure, and the percentage of high-risk foot increases in overweight and obese patients, suggesting the need of body weight control in these patients when administering offloading treatment for prevention of diabetic foot ulcer.