INVESTIGATIONS on articular replacement were undertaken as a result of discussions with the late Clay Ray Murray. He had for a long time been unhappy about the clinical outcome in subcapital fractures of the femur. Through long-term follow-up at Presbyterian Hospital it became clear that pinning, either open or lateral, was not the answer. The same was true with grafts across the fracture site or multiple drillings. Muscle transplantation, to give increased vascular supply, to the femoral head was likewise ineffective in altering the long-term clinical course.1 In high subcapital fractures with adequate reposition, pinning, and, sometimes, osteotomy, the results were poor. Occasionally, despite all measures and healing at the fracture site, aseptic necrosis and degenerative changes began to show between one and one-half to two and one-half years. Experiments were started in 1940.
In the animal experiments2 four objectives were sought: (a) a biologically inert material with