Cruciate Ligament Injuries in Dogs

Reposted from April 2008.
Cruciate ligament problems are more common with big dogs than small, and with dogs that run and jump (think Frisbee) rather than those who merely walk around in yard and kitchen.

Keeping a dog lean, and not obese, can help prevent injury.

Small dogs (under 20 pounds) will often regain almost normal function without surgery (although they may develop some arthritis).

Finally, with use of anti-inflamatories and time, a lot of dogs will recover on their own. And even if they don't, a limping dog may not necessarily be in pain. The idea that every problem needs a solution is probably a concept we need to disenthrall ourselves of. This, of course, is not something you are likely to hear from a veterinarian.

An $80 Pet's $12,000 Bill

A Human Jock's Ailment Plagues Pooches

This Joint Problem Makes Dogs, Owners, Weak In the Knees

By Kevein Helliker, Wall Street Journal April 11, 2006; Page A1

A dog named Paddi was chasing a cat through a suburban Seattle neighborhood when suddenly she pulled up lame. So tender was Paddi's hind leg that her owner, physician Kevin Bulley, had to carry her home.

The diagnosis turned out to be a ruptured cruciate ligament, an injury that Dr. Bulley, a family practitioner, had associated only with humans. Cruciate ligaments hold in place the parts of the knee, and wrong turns on the athletic field often injure these cords.

The cost of fixing Paddi's knee was about $3,000. She had barely recovered from that surgery when the cruciate ligament in her other knee ruptured, prompting a second $3,000 procedure -- all for a mutt that Dr. Bulley and his family had adopted and grown to love. "She's the most expensive free dog I've ever heard of," says the physician.

Being an athlete is a well-known risk factor for cruciate-ligament injury. A larger -- but lesser-known -- risk factor is being a dog. The number of dog knees undergoing cruciate-ligament repair each year in America is estimated to now exceed 1.2 million. That's about five times the number of human procedures -- even though humans outnumber dogs in the U.S. by nearly five to one. And it's not as though dogs have more knees: The joint on their front legs are elbows that aren't vulnerable to the problem.

Dog owners often have no idea that this danger exists. Pennsylvania engineer Martin Yester, for example, investigated the medical history of his yellow Labrador, Sarah, before purchasing her as a puppy. Knee risks didn't come up -- until her cruciate ligament ruptured in December. Even though certain larger breeds have been shown to be more susceptible, "nobody talks about knee problems," says Mr. Yester.

The extraordinary rate of failure in dog knees is mystifying even to veterinarians. Is the prevalence of such canine injuries rising -- or are people less willing to let their pets hobble on three legs? "It's a bit of a mystery as to the cause," says Steven Budsberg, a veterinary surgeon who is director of clinical research at the University of Georgia College of Veterinary Medicine.

Today, cruciate-ligament repairs are the most common surgical procedures for injured or diseased dogs. And inside veterinary medicine, controversy is raging over the best treatments.

A relatively new technique, called tibial plateau leveling osteotomy, or TPLO, involves breaking and resetting the tibia, the long bone below the knee, in such a way as to obviate the need for a cruciate ligament. The surgery costs from about $2,500 to $5,000 per knee. That's about twice the cost of the conventional procedure, which like the human equivalent involves constructing a replacement ligament.

Many respected academic veterinary experts believe that TPLO offers a faster and fuller return of function. But published proof of that theory is lacking, prompting some to avoid the procedure.

For instance, surgeons don't perform it at the University of Pennsylvania School of Veterinary Medicine, says Gail Smith, chairman of the department of clinical research. He calls TPLO "a fashionable procedure."

Still, TPLO now is used for an estimated 50% of cruciate-ligament procedures in the U.S., and by all accounts that percentage is growing.

Such treatments have helped fuel a doubling of the number of veterinary surgeons in the U.S. in the last decade to 1,219 from 660.

It is also the largest factor in a near doubling of the average annual cost of veterinary surgery visits -- to $574 in 2004 from $289 in 2000, says the American Pet Products Manufacturers Association.

Like Dr. Bulley, hundreds of thousands of Americans are digging deep into their pockets each year for a surgery most never realized a dog might need. A November article in the Journal of the American Veterinary Medical Association estimated that Americans spent $1.32 billion to fix dog knees in 2003.

Without surgery, only 20% of dogs will regain normal function, says Dr. Michael Conzemius, an Iowa State University veterinary surgeon and a co-author of the November JAVMA article.

Even if Americans increasingly consider dogs to be part of the family, health insurers don't. According to the pet products industry and insurers, fewer than 3% of dog owners have purchased a medical policy for their pet.

A spokesman for the largest pet insurer, Veterinary Pet Insurance of Brea, Calif., says that cruciate-ligament problems in dogs accounted for nearly $4 million in claims in 2004, and that no other condition had a higher cost per claim.

One claimant was David Wright, a San Jose software engineer who several years ago bought two Labrador Retriever mixes for $80 each. The male, Sage, tore the cruciate ligaments in both of his knees in 2002. "The $80 dog became the $6,000 dog," says Mr. Wright.

Then the female, Kenya, wrecked both of her knees. Of the $12,000 that Mr. Wright spent on those surgeries, he says Veterinary Pet Insurance reimbursed him about $5,000. "Thank God I had that insurance," says Mr. Wright, adding that reimbursement for other, non-knee-related medical expenses already had exceeded the premiums he'd paid.

Unlike human knees, dog knees don't lock -- their back legs are always bent. That means the ligaments of the joint are tense whenever the animal is standing.

This helps explain why canine cruciate tears often occur over time in middle-aged dogs, while human ruptures can happen at any age, and almost always result from an acute twisting or turning of the joint. As in humans, the dog knee contains two cruciate ligaments, and the front-most ligament is likeliest to tear. In humans this is called the anterior ligament, in dogs the cranial ligament.

Few warnings exist for puppy purchasers or dog owners. The Web sites of breeding clubs typically make no mention of cruciate-ligament injuries while offering warnings and advice about screening for hip problems in dogs. The Web site of PetSmart Inc., the nation's largest retailer of pet supplies and services, offers advice about problematic hips in dogs, but not knees.

Diane Dahm, an orthopedic surgeon at the Mayo Clinic renowned for her knowledge of cruciate-ligament troubles in humans, says she isn't familiar with similar canine issues. "I'm aware of hip dysplasia in dogs," she says.

In fact, hips troubles aren't as common as canine knee problems. But hip problems have received attention in part because of a proven genetic component. Puppy buyers can demand certification of a family history free of hip dysplasia, a debilitating condition in which the ball and socket don't fit well together.

Some research suggests that cruciate-ligament tears also bear a genetic component. There always had been anecdotal evidence: For instance, Mr. Wright's two affected dogs are half siblings. An article in the January issue of the Journal of the American Veterinary Medical Association identified a gene that appears to predispose Newfoundlands to cruciate tears. Eventually, this discovery could lead to a test that would identify carriers of that gene, ideally enabling breeders to screen out problematic dogs.

Even now, some doctors say purchasers of puppies belonging to the larger, more at-risk breeds -- Labrador Retrievers, German Shepherds and such -- should ask about family history of cruciate-ligament disease. "Unfortunately, there's little you can do at this point except ask about it," says Dr. Conzemius.

For many pet owners, the thought of spending thousands of dollars on a dog knee remains laughable. "I'd never spend more than $300 on a dog, no matter how much I loved it," says Roger Holwick, whose eastern Kansas farm is home to eight dogs.

The fastest, an Australian Shepherd, has a bum leg that Mr. Holwick never considered getting fixed. "She rules the roost, and she doesn't even know she has a disability," he says.

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