PITTSBURGH, June 15, 2007 After UPMC orthopaedic surgeon, Freddie Fu, M.D., performed the first-ever arthroscopic knee surgery on a mandrill at the Pittsburgh Zoo & PPG Aquariums veterinary hospital on June 13, Dr. Fu is even more convinced of the importance of the posterior lateral (PL) bundle of the knees anterior cruciate ligament (ACL) in humans.
Dr. Fu, along with the zoos chief veterinarian Dr. Cindy Stadler and orthopaedic veterinarian specialist Dr. John Payne, collaborated on the exploratory surgery in an effort to discover what was causing obvious discomfort and instability in the left knee of the 11-year-old mandrill named Johnny.
In the operating room, the hour-long arthroscopic examination revealed a partially torn anterior cruciate ligament (ACL). More specifically, the doctors found that one of the three fiber bundles of the ACL, the posterior lateral (PL) bundle, was beyond repair. The other two bundles of the mandrills ACL(the anterior medial and the inter-medial bundles) both were intact.
Although it was impossible to restore the PL bundle itself, Dr. Fu used arthroscopic instruments to remove scar and inflamed tissue that had built up over time and was causing Johnny's discomfort. The procedure seems to have helped reduce inflammation and pain in Johnny's knee joint and he continues to do well, according to his keepers.
I give a lot of credit to Johnny's keepers for noticing his discomfort and picking up that he had an injury to his knee. The fact that his keepers observed the immobilizing effects of his injury, which we know now was specifically his PL bundle, further proves to me the importance of the PL bundle to joint rotation and stability in mandrills and maybe in humans too, said Dr. Fu. Even with just a partially torn ACL, the mandrill wasn't completely functional.
In working with Dr. Fu, we are taking a major step to advance the care of animals and humans, said Dr. Barbara Baker, president and CEO of the Pittsburgh Zoo & Aquarium.
Not only did the arthroscopic procedure provide answers for Johnny's benefit, but it also provided valuable information for Dr. Fu and his research team in their ongoing quest to learn as much as possible about the complete anatomy and function of the knee joint in both animals and humans.
The more we know about the functional anatomy of the knee joint in both animals and humans, the better we can approach human ACL reconstruction for the best possible outcomes for human patients, said Dr. Fu, who is professor and chairman of orthopaedic surgery at the University of Pittsburgh School of Medicine. For example, we learned today for the first time that the mandrills ACL has three bundles of fibers as compared to the humans two bundles. That may be because of the
mandrills need for more rotational stability in the knee compared to humans, explained Dr. Fu, who is an international pioneer in developing the concept of double-bundle ACL reconstruction in humans. In traditional ACL reconstruction over the years, surgeons have generally replaced the ligament with only one single bundle. Dr. Fu and a few other surgeons worldwide several years ago had begun to recognize that the human ACL is actually made of two bundles, each serving different important functional roles in the rotational stability of the knee. Therefore, Dr. Fu believes that to better restore the natural anatomy, rotational stability and complete function of injured ACLs in humans, the two bundles of the ACL must be precisely replaced.
As surgeons, we must pay close attention to the anatomy. After having performed thousands of ACL reconstructive surgeries since 1982 and more than 400 double-bundle ACL reconstructions on humans, I am still learning about the anatomy, said Dr. Fu We also learned that the symptoms of ACL injury in a mandrill are similar to those in humans. But for wild animals, they don't do sports. They do everything for life, to survive. That's probably why they have more bundles of the ACL.
In our continuing effort to provide the best care possible for our wonderful animals, the partnership with Dr. Fu is charting a new path in the world of medical and veterinary science, added Dr. Baker. We are so fortunate to have world-class expertise in our own community and are appreciative of all of his effort and enthusiasm to help our mandrill. Dr. Fu's research will advance the care of animals and humans.
Dr. Fu also is working with the Carnegie Museum of History to obtain resources for his ongoing research of how the knee has evolved and how it functions in many different species. ACL tears are among the most common injuries in active people, causing painful knee instability. If not repaired properly, ACL injuries can lead to the onset of osteoarthritis and cartilage damage.
Using specimens of different species in the Carnegie Museums collection, Dr. Fu's team studies the bony landmarks of the animals ACL insertion site on the bone, which provide clues of the ACL size and number of bundles. It was Dr. Fu's research and interest in the ACL of monkeys that ledto the partnership with the Zoo.
Zoo keepers believe Johnny had injured his knee over time due to his natural aggressive activities. They began to notice that Johnny was uncomfortable. At different times, he would smack his left knee, pinch it, and at times it would not be able to support his weight, said Suellen Stanley, Johnny's primary keeper. Since primates in general have a higher tolerance to pain, the keepers knew his behavior was indicative of a serious problem. Dr. Stadler examined Johnny and was researching options for diagnosis and treatment when Dr. Fu called her regarding his research of the ACL bundles.
When Dr. Fu and Dr. Stadler together observed Johnny, Dr. Fu recommended an MRI. Pets DX and Medical Director Dr. Gerald Fry were eager to help with the mandrill. At the conclusion, the MRI was not able to show definitively if the ACL was damaged. The decision was then made to perform an arthroscopic scope of the area to diagnose the problem and correct it, if possible.
Johnny was born at the Pittsburgh Zoo in January 1995. He is one of three males and a female at the Zoo. Since most mandrill males are solitary animals, often, males are aggressive with one another. Johnny is more aggressive with the other males, so he is most often on exhibit by himself. He is sweet, says Ms. Stanley, He likes to act tough, but he loves the attention we give him.