Improved fixation of the femoral component after total hip replacement using a methacrylate intramedullary plug.

When the distal part of the medullary canal of the femur was plugged with a bolus of methylmethacrylate prior to the insertion of cement and femoral component, fixation of the prosthesis was improved in vitro. A special syringe was devised to introduce the plug at the desired level. When the plug was used, the penetration of the cement into the trabecular bone lining the canal was increased, and subsequent push-out tests showed that the force necessary to disrupt the methacrylate from the bone was significantly greater. Casts of the methacrylate from femora with and without plugged canals showed that the surfaces of the casts made with the canal plugged conformed much more completely with the irregularities of the bone and provided more intimate contact at the cement-bone interface.