Investigation of Shore meter in assessing foot sole hardness in patients with diabetes mellitus - a pilot study

Understanding the biomechanical properties of the diabetic foot may detect the foot at risk of ulceration. Increased foot sole hardness and the peripheral neuropathy are suggested to be important risk factors for foot ulceration, in subject with diabetes. Therefore this study was to investigate the feasibility of measuring and variation of foot sole hardness in patients with diabetes. Assessment was performed on 30 subjects aged from forty to seventy years, classified into three groups: 10 subjects with diabetic neuropathy (Group A), 10 subjects without diabetic neuropathy (Group B) and 10 non-diabetes subjects without neuropathy (Group C). Subjects underwent an assessment of loss of protective sensation (LOPS) by means of a 10 gm Semmes Weinstein monofilament and measurement of foot sole hardness by means of a durometer (ASTM-D 2240) or shore meter in eight foot sole areas. Imperceptions of the 5.07 / 10 gm Semmes-Weinstein monofilament at four or more of the eight foot sole areas was considered the threshold for neuropathy. Data was analyzed using ANOVA to detect significant difference between the groups and also Dunnett’s pair wise multiple comparison t-tests was used to compare Groups A and B against the control mean (Group C). Our result shows statistical significant (P < 0.05) differences between Groups A and C in all foot areas, except area 6. Also significant differences were found in areas 5, 7 and 8 while comparing Groups B and C in both feet. We conclude that difference and variation in foot sole hardness were found to be significantly different in subjects with and without diabetic neuropathy using shore meter. Hence shore meter was more sensitive and provided a feasible means of measuring foot sole hardness in subjects with diabetic neuropathy. Foot sole hardness in diabetic feet can be considered as potential determinant of the foot sole ulcerations.