Researchers removed the entire humeral head -- the ball part of ball-and-socket shoulder joints -- from rabbits used as test subjects and then implanted the scaffolds to grow a biological replacement for the missing piece.
The study reported that the rabbits implanted with the drug-infused scaffolds were able to use the joints and support themselves with them faster and more consistently than rabbits not given the scaffolds. After four months, a new cartilage surface for the humeral head had grown in place, with no complications or adverse effects, the researchers reported.
"They've been able to demonstrate that using a specific type of scaffold that's been doped with a specific type of growth factor, cells will basically populate the scaffold and create cartilage," Einhorn said.
Though apparently sound, the process still faces years of testing, mainly because it involves the use of an experimental cell growth factor, Einhorn and Cook said.
"We feel that clinically it works, but there's still a lot of safety testing on the human side to get [U.S. Food and Drug Administration] approval," Cook said. "The FDA wants to see it's safe, it's the same product every time, and there are no problems with disease transmission or infection."
Einhorn said the durability of the biological joints also must be considered.
"The stability needs to be tested," he said. "Is it going to be able to withstand the wear and tear that occurs through use on a daily basis, or is it something that just looks good now but will break down quickly?"
Cook has high hopes that the biological replacement joints will prove superior to the artificial joints now used, providing recipients with a higher degree of function.
"A metal and plastic joint is at its best condition the day you put it in," he said. "The plastic wears out. Even the metal can wear out. A biological joint can actually improve over time as it adapt
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