Cryopreservation of periosteum for transplantation

The concept of biological joint resurfacing has been widely studied, with encouraging results to date in both animal and human experiments. Most investigators have studied autograft tissue, however, in the clinical setting, situations might arise where autografting would not be suitable. We were therefore interested in developing a method of storing allograft periosteal tissue for biological joint resurfacing. A total of 192 periosteal grafts were harvested from 48 New Zealand White rabbits using sharp dissection (to include the cambium layer of progenitor cells). The free grafts were placed in a culture medium containing the cryopreservative dimethyl sulfoxide, then cooled at a controlled rate in a programmable freezer at rates of -0.5, -1.0, -2.0, or -10.0 degrees C/min. Viability of the grafts was assessed upon thawing after frozen storage for 8 days or 4 months using autoradiography and radioactive isotope uptake into newly synthesized proteins. Fresh, noncryopreserved and killed grafts were used as controls. A rate of cooling of -1.0 degrees C/min yielded viability results that were not significantly different from those of fresh controls. Furthermore, there was no change in viability as measured by radioactive isotope uptake over 4 months of storage. These results indicate that cryopreservation is a simple and efficient means of storing periosteal tissue for up to 4 months.