Objective: To investigate the effectiveness of injecting liquid silicone in the diabetic foot to reduce risk factors for ulceration in a randomized double-blind placebo-controlled trial.
Research design and methods: A total of 28 diabetic neuropathic patients without peripheral vascular disease were randomized to active treatment with 6 injections of 0.2 ml liquid silicone in the plantar surface of the foot or to treatment with an equal volume of saline (placebo). No significant differences were evident regarding age or neuropathy status between the 2 groups. All injections were under the metatarsal heads at sites of calluses or high pressures. Barefoot plantar pressures (pedobarography) and plantar tissue thickness under the metatarsal heads (Planscan ultrasound device) were measured at baseline and at 3, 6, and 12 months after the first injection. Injection sites were photographed at all stages, and callus formation was scored as a change from baseline. Throughout the study, patients were treated by the same podiatrist for all podiatry treatment.
Results: Patients who received silicone treatment had significantly increased plantar tissue thickness at injection sites compared with the placebo group (1.8 vs. 0.1 mm) (P < 0.0001) and correspondingly significantly decreased plantar pressures (-232 vs. -25 kPa) (P < 0.05) at 3 months, with similar results at 6 and 12 months. A trend was noted toward a reduction of callus formation in the silicone-treated group compared with no change in the placebo group.
Conclusions: The results confirm the efficacy of plantar silicone injections in reducing recognized risk factors associated with diabetic foot ulceration.