Comparison of a polymethylmethacrylate and glass-ionomer bone cement using a hemiarthroplasty in the rabbit femur

Polymethylmethacrylate (PMMA) bone cements present various problems with respect to biocompatibility and stability. In order to study the histological changes at the bone-cement interface following total hip replacement, a small animal model was created by implanting hip prostheses using two different bone cements (PMMA and glass-ionomer cement, GIC). Two problems with the use of GIC for fixation of the prosthesis became evident. One year following implantation, histomorphometric analysis of femurs containing the GIC demonstrated significantly higher amounts of osteoid at the bone-cement interface. This disturbance of mineralization is comparable with osteomalacia and probably due to leaching of aluminum ions. In addition the mechanical properties of GIC proved to be inadequate for the loads placed upon it in this hip replacement model.