The amount of repair and the time required to accomplish repair of
four-centimeter segmental fibular transplants in twenty-one male adult dogs
were determined at from two to forty-eight weeks after transplantation by
torsional stress testing, microradiography, and tetracycline labeling. The
transplanted cortical bone was greatly weakened at from six weeks to six
months but was nearly normal at one year. The strength of the transplant
appeared to be related to the amount of porosity of the matrix rather than
to the quality or completeness of biological repair. Spatially, the repair
was ordered rather than random. The initial resorption caused increased
porosity which was slowly offset by apposition of new bone, a process which
was dependent on general skeletal metabolic activity. Although physical
strength was near normal at forty-eight weeks, only 60 per cent of the
transplants had been remodeled.