Replacement of epiphyseal bone with methylmethacrylate: its effect on articular cartilage.

Methylmethacrylate cement was used as a substitute for the epiphyseal bone of the canine proximal femora, after femoral neck osteotomy. The effects of different volumes of acrylic cement on the integrity of trabecular bone and articular cartilage and the effects of different types of fixation of the osteotomy site were assessed clinically, radiologically and histologically. Degenerative changes occurring in the articular cartilage were greatest when a large area of epiphyseal bone was replaced with methylmethacrylate. These degenerative changes varied proportionately with the rigidity of fixation at the osteotomy site. Rigid fixation resulted in a better clinical and radiographic assessment and a decrease in histopathologic changes in the articular cartilage.