Bone reaction to silicone metatarsophalangeal joint-1 hemiprosthesis.

The incidence of inflammatory response to silicone implants in the first metatarsophalangeal joint was investigated. In 34 of 59 silicone arthroplasties, cysts were noticed in the proximal phalanx after a mean follow-up period of 59 months. In the metatarsal head, cysts were seen in 40 cases. Histologic examination showed that the cysts were filled with an avascular cellular stroma containing histiocytes and multinucleated giant cells, opsonizing wear debris of the prosthesis. Because of this destructive process, caution is advised when using silicone prostheses in young, active people.