Sometimes forward-thinking means looking back 50 million years.
In an effort that, if successful, could re-write medical textbooks and revolutionize knee surgery, Dr. Freddie Fu has turned to the fossil record and zoo animals to learn more about the anatomy of the human knee.
"I'm somebody with maybe a little bit different ideas than other doctors," said Fu, chairman of the University of Pittsburgh Medical Center's department of orthopedic surgery.
Today he plans to perform knee surgery on Johnny, a 99-pound, 12-year-old Mandrill monkey with a damaged left knee at the Pittsburgh Zoo & PPG Aquarium. While repairing Johnny's knee -- the first knee surgery on a Pittsburgh zoo animal -- Fu will peek at how it's put together.
It's part of a partnership he has forged with the zoo and Carnegie Museum of Natural History. By examining fossils, the remains of zoo animals that died of natural causes, and living animals, Fu and his students say they found evidence to support a knee surgery Fu learned from Japanese surgeons and pioneered in the United States -- called the "double-bundle" procedure.
"In the lab this looks very promising," said Dr. Frederick Azar, a surgeon at Campbell Clinic, an orthopedic center in Memphis. "We just don't know how it's going to translate into patients, if it's going to be worthwhile.
"It's technically more demanding, and I think that's why it hasn't caught on with other orthopedic surgeons in this country."
The anterior cruciate ligament, tissue that connects the shin to the thigh bone, is made of fibers that act like a stiff rubber band, allowing the knee to move while holding bones together. In most people the fibers are grouped into two bundles -- a large one that allows the knee to bend and smaller one that lets it twist.
When the ACL tears -- something that happens to 200,000 people in the United States each year -- almost all surgeons replace only the larger bundle with a single graft of healthy tissue from the patient's hamstring in a formulaic surgery that, with practice, can be done in less than 30 minutes.
Fu used to be one of those surgeons. During his career, he has fixed more than 5,000 ACL tears, sometimes performing a dozen surgeries a day. Then he took a closer look at the knee, and decided the single-bundle operation -- although adequate -- did not accurately mimic the knee's anatomy.
"You're born with two bundles, you live with two bundles and you die with two bundles," Fu said. "But when you get surgery, then you have only one bundle."
In addition to gathering data on long-term outcomes of patients who get double-bundle ACL repairs, Fu is mining the fossil record at the natural history museum to trace the evolution of the double-bundle. Dr. Sheila Ingham, a post-doctoral research fellow from Brazil, is studying with him.
Even the 50 million-year-old knee of the extinct Shoshonius -- a big-eyed monkey weighing only a few ounces -- had a double-bundle. Tiny "bony landmarks" on fossilized knee bones stored at the Oakland museum show where the ligaments were attached.
"He's got the full force of the fossil record on his side," said Chris Beard, curator of vertebrate paleontology at the museum. "Biology is telling us that it is very important to have this double-bundle structure."
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