A suitable plastic, a rigid polyurethane foam (Ostamer *), which can be poured in liquid form and has properties of strength, osteogenesis, nontoxicity, cohesiveness, and ease of handling at surgery, has been used by us in 35 cases to date. It is the purpose of this paper to review these cases. Ostamer is the most extensively studied plastic used to date in the human body. Experiments have been progressing for four years to ascertain the toxicology, absorption, metabolic route of excretion, osteogenetic properties, and strength potential of Ostamer. Without reservation it can now be stated that Ostamer has the strength per square inch and the adhesiveness necessary for bone fixation, and it also provides a chemical lacunar system (Fig. 1). New bone, a notorious creeper when given a suitable medium, not only climbs along the surface, but grows through the plastic, as would be expected with an autogenous graft. This, therefore,