A COMPARATIVE-ANALYSIS OF SUBCHONDRAL REPLACEMENT WITH POLYMETHYLMETHACRYLATE OR AUTOGENOUS BONE-GRAFTS IN DOGS

A comparative analysis was made of subchondral replacement with polyme thylmethacrylate and autogeneic bone grafts in defects in the medial f emoral condyles of dogs. The defect produced a 50% reduction in subcho ndral stiffness. An in vitro preparation helped establish that subchon dral stiffness returned to normal after reconstruction with polymethyl methacrylate. The in vivo model demonstrated a reduction in subchondra l stiffness in both groups at three weeks, but the bone grafted side r eturned to normal and the methylmethacrylate side recovered to 79% of the control at 12 weeks. There were no deleterious effects on the arti cular cartilage in either group when analyzed histologically and bioch emically. A marked increase in new bone formation and subchondral poro sity was found in the polymethylmethacrylate groups. This study suppor ts the clinical use of subchondral polymethylmethacrylate after the ex teriorization and curettage of benign bone tumors such as giant cell t umors.