Laterality of lower limb amputation in diabetic patients

Editor—Foot ulceration affects as many as 15% of patients with diabetes; Mancini and Ruotolo estimated that 6-20% of all patients in hospital with diabetes have foot ulcers.¹ A recent retrospective study of amputations in people with diabetes noted a striking laterality, with nearly all occurring on the right side.² The main predisposing factors to ulceration (peripheral vascular disease, neuropathy, and infection) cannot adequately explain this observation.

We therefore postulated that the excess of right sided amputations in patients with diabetes might be related to right or left sided dominance (that is, right or left footedness) since this might be expected to determine which foot is used most for starting or stopping movement. A dominant foot might be subjected to greater shearing or mechanical stresses or might be more susceptible to injury by accident.

Twenty five patients with unilateral foot ulceration attending a specialist foot clinic at a district general hospital over four weeks were questioned as to whether they were right or left handed/footed, and we recorded the site of their current foot ulceration. Twenty four of the patients were right footed, of whom 18 had ulceration on the right foot. Compared with the expected number of 12 (assuming equal left/right predominance of ulcers), this was significant (χ²=6, P<0.02). The single left footed patient had an ulcer on his left foot.

Our data therefore support Coxon and Gallen’s finding that foot ulceration in people with diabetes is more common on the right. Given the relatively small numbers of patients who are truly left footed, a much larger study is required to confirm these observations. We conclude that all diabetic feet at risk should be reviewed regularly, with particular attention being paid to the dominant foot.