Detecting intrinsic muscle weakness of the hallux as an addition to early-stage screening of the feet in patients with diabetes

Aims: Present-day screening of the diabetic foot involves the Semmes Weinstein Monofilament Test for evaluating loss of sensibility, while testing for intrinsic muscle weakness is not implied. Just as with the early detection of sensibility loss, early detection of intrinsic muscle weakness might have important implications for the prevention of both ulceration and deformity in patients with diabetes. The purpose of this study is to investigate the prevalence of patients with diabetes presenting intrinsic muscle weakness of the hallux, but with a normal sensibility of the sole of the foot.

Methods: A cross-sectional study design was applied. Intrinsic muscle function of the hallux was measured with the Paper Grip Test, while sensibility of the sole of the foot was measured with the Semmes Weinstein Monofilament Test 5.07/10-g.

Results: In a period of three months a total of 266 patients with diabetes (mean age 60, 134 females (50%), 177 type 2 diabetes mellitus (67%)) met the inclusion criteria and were examined for both intrinsic muscle weakness of the hallux and sensibility of the soles of the feet. The results showed that intrinsic muscle weakness was present more frequent in patients with impaired sensibility (P=0.001), also 20% of the population had intrinsic muscle weakness in the presence of normal sensibility. Multivariate regression analysis showed that only age is associated with patients with diabetes presenting normal sensibility but impaired intrinsic muscle function (P=0.017).

Conclusions: The Paper Grip Test could have added value to current physical examination of the feet in patients with diabetes.