A canine cementless total hip prosthesis model.

To evaluate a porous fiber titanium composite as a fixation method, total hip arthroplasty was performed in 13 large male mongrel dogs. In seven both acetabular and femoral composites were fixed with a porous titanium fiber composite, and in the other six the acetabulum was fixed with acrylic cement. The animals were killed one, three, and six months following implantation. At autopsy all components were fixed by bony ingrowth. There was progressive remodeling of the ingrown bone and of the bone trabeculae surrounding the prosthesis in the three- and six-month animals, with gradual thickening and development of haversian structures. Cortical osteoporosis, which did not appear to be progressive, was detected in both the one- and six-month specimens.