Injectable silicone and the foot: a 41-year clinical and histologic history.

BACKGROUND: Since 1964, the author has investigated injectable liquid silicone as a soft tissue substitute for the loss of plantar fat. This form of fatty tissue depletion over the sole is closely linked to a common painful weight-bearing foot disorder, metatarsalgia, and to painless diabetic foot ulcers.

OBJECTIVES: To present the history of injectable silicone, corporate interest, individuals who helped pursue approval, its misuses, and events that have delayed its availability.

MATERIALS AND METHODS: Dow Corning Corporation's 360 Medical Fluid of 350 centistoke was injected beneath corns and calluses in 1585 patients. Diabetic neuropathic foot ulcers were injected after healing in an effort to prevent their recurrence. Surgical and postmortem specimens were gathered for histologic analysis.

RESULTS: There was no evidence of significant adverse response in long-term clinical follow-up. Silicone specimens studied by two departments of pathology found no inflammation, infection, allergy, or granulomas.

CONCLUSIONS: Medical Fluid silicone appears to be safe, effective, and stable biomaterial for treating weight-bearing loss of plantar fat. Trademarked PodiSil (Richard-James Inc., Peabody, MA, USA), a 350-centistoke injectable silicone has been approved for marketing in Europe for the prevention of diabetic foot ulcers.