In a paper to be presented at an upcoming meeting of the American Orthopaedic Society for Sports Medicine, MSU scientists said their research shows the method, known as lyophilization or freeze-drying, does not improve the safety of bones and tissues for transplantation, something that could affect thousands of transplant recipients.
"We were able to demonstrate that this type of tissue processing does not inactivate systemically infected tendon and bone tissues," said Steven P. Arnoczky, the Wade O. Brinker Endowed Professor of Surgery in MSU's College of Veterinary Medicine and one of the lead researchers in the project. "Contrary to currently held clinical beliefs, lyophilization should not be relied upon as an extra measure of security for processing connective tissue allografts."
Bones, ligaments and other tissues that will be used for orthopedic transplants frequently are treated with gamma irradiation or a chemical "cocktail" in an effort to remove any bacteria or viruses which may have evaded the rigorous donor-screening process.
However, these methods can create additional problems, as they sometimes change the tissue's biological and biomechanical properties.
A clinical study published in 1985 suggested that lyophilization may inactivate HIV. Therefore, many surgeons who were seeking an extra measure of protection for their patients would specifically request tissues that had gone through the lyophilization process.
"This has completely changed a long-held belief," Arnoczky said, "and it's a very important contribution, as it got rid of the false sense of security people had with that process."