Structure of capsules around silicone implants in hand surgery.

Histological examination was made of twenty-three capsules around silicone implants used in hand surgery. The structure of the capsules was found to be similar to that seen in animal experiments, though they tended to be thicker. A further difference was the frequent occurrence of histiocytes accumulating near the inner margin of the capsule; these would quite frequently form a pseudoepithelium. Possible reasons for these differences are discussed. Silicone particles were found in the walls of two capsules around joint implants and their origin from the surface of the prosthesis demonstrated.