Experimental evaluation of a resorbable intramedullary plug for cemented total hip replacement.

In order to evaluate degradation kinetics and biocompatibility of a resorbable poly(D,L-lactic acid) (PDLLA) plug for total cemented hip prostheses, an experimental in vitro and in vivo study was carried out. Degradation rate studies were performed in Ringer solution and after in vivo plug implantation in the femoral medullar cavity of rabbits. In vitro biocompatibility was evaluated in murine fibroblast cell cultures. PDLLA plugs showed faster degradation kinetics in vivo than in vitro. Histological evaluations showed that PDLLA completely disappeared in vivo 26 weeks after implantation. Fibrous tissue in the medullar cavity was observed at 13 weeks, but no histological changes were observed after 26 weeks. Also, the in vitro tests showed good biocompatibility of the biomaterial. Our results show the possibility of considering this resorbable plug for clinical situations instead of the traditionally used plugs [polyethylene, poly(methyl methacrylate) or cancellous bone] due to its biocompatibility, degradation properties and simplicity of use.