People
A New Lease on Legs
Vet surgeon heads team hoping to ease knee arthritis pain
BY ANDREW VOWLES
Mere days after running a 10-mile race in late December, Prof. Mark Hurtig pops up from his chair with no sign of lingering aches in his trim fifty-something frame. Standing and swaying his legs from side to side, he says: “I have probably the worst knee alignment in the world.”
Take his word for it. The clinical studies professor knows knees — his own and those of numerous people nursing the kinds of common joint problems that he studies here at Guelph as the leader of a national arthritis research group.
Not that Hurtig himself suffers from those ailments. Even that self-confessed misalignment has not held the 53-year-old back from such activities as running marathons, competing in Iron Man triathlons and skiing through the French and Swiss Alps. But his own experience and active pursuits — including some embarked upon only as mid-life challenges — give him a personal perspective on a vexing and often debilitating disease that he hopes to alleviate through his research at U of G.
As a faculty member in the Ontario Veterinary College, Hurtig runs the Comparative Orthopedic Research Lab. That's actually a suite of offices and labs housed not in the main OVC building but in the Equine Sciences Building located at the corner of McGilvray Street and Smith Lane. Horses are the primary focus of his neighbours, as evidenced by the animals standing in the adjoining paddock near his office on one winter morning. But the lab isn't quite so anomalous here as it seems, says Hurtig, pointing out that his work with OVC colleagues extends to studying leg injuries in racehorses and using animal models to study human disease progression.
Improving the diagnosis and treatment of knee arthritis in people is his purpose as director of the lab, which is affiliated with the Canadian Arthritis Network (CAN), part of the national Networks of Centres of Excellence program. And it's the goal of a substantial research project involving several institutions across Canada under the Guelph researcher's leadership. Hurtig heads the “Proknee” (www.proknee.ca) collaboration as the principal investigator in a five-year research project funded by the Canadian Institutes of Health Research. Together, its clinicians and scientists aim to develop tools to help doctors predict how osteoarthritis will develop in patients after a knee injury and reconstruction — a step toward the ultimate goals of treating and perhaps staving off the disease.
How does a veterinary surgeon wind up in the middle of a research collaboration intended to heal human knees? Voicing a sentiment sure to resonate with many of his OVC colleagues, Hurtig says vets often provide the glue connecting disciplines from epidemiologists and psychologists to surgeons and radiologists to engineers.
“Veterinarians get a really broad training that allows them to learn the language of other disciplines effectively,” he says. “You turn out to be a translator between these different groups.”
Besides burrowing into the hard-core cellular and molecular biology underpinning the disease, “we're interested in how behaviour and psychosocial aspects of life affect the ability of people to cope with bone injuries.”
If you've suffered a knee ligament injury, you're virtually guaranteed to run into problems with osteoarthritis later in life. The most common form of arthritis, it occurs when cartilage breaks down and allows bones to rub together. It's particularly common among professional athletes, notably soccer players, following reconstruction of the knee's anterior cruciate ligament (ACL). Not only can the injury be career-limiting, says Hurtig, but also “a high proportion of those people end up with osteoarthritis 10 or 20 years later.”
Doctors can tell you about the links between a damaged knee and later osteoarthritis. What the physicians and researchers are less sure about is just how rapidly the disease will develop and what effect your lifestyle choices will have on that progression. That depends on all kinds of factors, from your body mass index to your activity level to your propensity for taking risks. (Doctors call their patients knee “abusers” or knee “copers.” The former try to keep on going; the latter alter their activities to accommodate their injury.)
“We're interested in the many things that could be driving progression,” says Hurtig.
His team doesn't expect to be able to cure osteoarthritis. No drugs are currently available to stave off the disease. And doctors lack sound techniques for fixing all the damaged tissue, never mind being able to persuade those knee abusers to mend their self-destructive ways.
There's hope from emerging therapies and new reconstruction techniques, but those treatments are expensive. Finding the best cost-benefit balance will come from identifying higher-risk patients early before osteoarthritis has progressed.
That may benefit not just patients but also an increasingly overburdened health-care system. In Canada, the economic impact of osteoarthritis is estimated at more than $3.4 billion a year. Along with back pain, cardiovascular disease and allergies, it's among the most common chronic diseases. According to the 2000 Canadian Community Health Survey, arthritis and other rheumatoid conditions affect about four million adults in Canada — a number expected to exceed six million by 2025. Osteoarthritis affects more than 10 per cent of North Americans, with the knee being the most common weight-bearing joint affected.
The clinical arm of the Proknee study involves researchers based mostly at hospitals in Toronto. Here in his suite of labs, Hurtig will help run cadaveric and animal-modelling studies to learn whether mathematic modelling may predict osteoarthritis progression after ACL injury. Using finite element analysis, a team led by Saeed Shirazi-Adl in the mechanical engineering department at Montreal's Ecole Polytechnique can break down a knee's movement into a detailed series of freeze frames and study stress effects “in silico.”
That work draws on Hurtig's long-standing ties with researchers across campus in the physical and biological sciences. Using a robotic joint simulator in the laboratory of Prof. Jim Dickey, Human Health and Nutritional Sciences, they will measure forces affecting normal and damaged knees. That kind of comparative work will also benefit from the imaging know-how of engineering professor Karen Gordon. A graduate of Guelph's biological engineering program, she used magnetic resonance imaging to study osteoarthritis in knees as a post-doc in Calgary before joining U of G just over two years ago.
This is the only study of its kind in Canada (in the United States, the National Institutes of Health is leading a similar study of risk factors). Hurtig hopes to see results feeding into health-care policy within the five-year time frame of the study, due to end in 2010.
The goal is to lengthen people's so-called active phase after a knee injury, says Hurtig. The longer people maintain an active lifestyle, the fewer health problems they'll probably encounter, he says. As a case in point, the Guelph professor keeps up his own active schedule outside his labs. He competed in two half-Ironmans last summer; in 2005, he reached the Canadian Ironman in Penticton, B.C. “Fun and interesting” is how Hurtig describes the event, which puts competitors through a 2.4-mile swim, 112-mile bike ride and 26.2-mile run.
Disavowing any claim to being a gifted athlete, he says he began serious training only about six years ago. Today he trains “carefully,” usually spending one or two hours at a time, six days a week. He and his wife, Rhonda, now help run children's and women's triathlons in Milton.
Having recovered from an ACL injury sustained three years ago while playing ball hockey, Rhonda competed in last year's Ironman Canada triathlon.
Says Mark Hurtig: “I'm a pretty average age-group athlete and will never be an exceptional performer. I decided a long time ago that it was better for people to participate at any level rather than take a passive role and watch others. It seems like so many of us are willing to live vicariously by watching professional athletes rather than developing the fitness and skills ourselves. I appreciate amateur and professional athletes much more after trying a sport. Ever tried surfing? It gives you new respect for surfers. Outdoor activities, particularly in challenging or remote environments, keep me in touch with nature and renew my respect for the natural world.”
Among his recent outings, he scaled the technically challenging east ridge of Mount Temple, the highest peak in Alberta's Bow Range at 3,540 metres. Hurtig has also completed the Haute Route ski tour, a week-long expedition that takes advanced skiers from Chamonix in France to Zermatt in Switzerland.
“That was quite spectacular and interesting from a cultural point of view,” he says. “While we might consider that type of travel in winter to be risky here in North America, in Europe it's a respected and time-honoured pastime that people engage in into their 60s and 70s — another example of how cultural attitudes influence activity, fitness and wellness.”
Trading snow for water, he plans to visit Six Mile Lake in the Muskokas this summer to help another engineering colleague, Prof. John Runciman, test performance attributes of a slalom water ski made by an American company.
“John and I have co-supervised students and worked together on projects involving bone and reconstructive surgery for joint injuries. I can't lay any claims to being an expert water skier in my youth, but I'm the skill level and body weight John was looking for.”