Growth factors embedded in an agarose matrix enhance the rate of porous polyethylene implant biointegration

Purpose: Repeated injections of epidermal and basic fibroblastic growth factors have been shown to enhance the biointegration rate of implanted porous polyethylene. A study was done to determine whether agarose, introduced at the time of implant placement, might serve as an adequate 'single dose' delivery system for endogenous and exogenous growth factors. Methods: Polyethylene cubes coated with agarose-containing growth factors were implanted into fat and muscle in rabbits. Factors studied included autogenous whole blood, autogenous serum, ascorbic acid, epidermal growth factor, basic fibroblast growth factor, transforming growth factor alpha, and transforming growth factor beta. The rate and character of the fibrovascular ingrowth into implants and surrounding capsule thickness were assessed. Results: Fibroblast infiltration enhanced two- to sixfold with the use of autogenous or allogenic factors introduced in an agarose matrix at the time of cube implantation. Conclusions: Growth factors studied altered the thickness of the capsule surrounding implants as well as both the vascularity and stromal density within implants.