Osteocartilaginous allografts (distal femurs of rats) were stored at 4° for six, 12, 24, and 48 hours and at −80° for five days and then evaluated for viability of the bone and cartilage. Storage at 4° for 12 or 24 hours had little effect on cartilage viability but decreased bone viability to 40% and 10% of controls, respectively. Storage at −80° for five days resulted in nonviable bone in all cases but showed an either/or response of cartilage, with high viability in two cases and nonviability in the other eight cases. In a second set of experiments, femurs from rats were stored in situ at 4° for 12 or 24 hours or were harvested and stored at −80° for five days, after which they were transplanted into rats of a different strain. The antibody response to each set of femurs was measured at two, six, and 12 weeks after operation. The 4° storage resulted in a moderately decreased immunogenicity, whereas the storage at −80° resulted in significantly reduced immunogenicity.
From the Departments of Orthopaedic Surgery, University of California, Davis, and University of California, San Francisco.