Ok, I'll admit it - I'm a huge Harry Potter fan. Anyone who knows anything about Harry Potter knows about the horrible, forbidden "cruciatus curse," which causes the intended victim to writhe in excruciating, agonizing pain.
I know of a real-life injury that can cause a similar terrible pain - a torn anterior cruciate ligament. It's a condition that can occur in anyone with knees. For most, this injury is a traumatic one, and is the result of a tremendous external force on the knee.
Football players typically sustain cruciate ligament injuries when hit in the knee by another player. Cats usually acquire cruciate ligament injuries when hit by a car, as they generally avoid being tackled by football players. Interestingly, cruciate ligament injuries can occur spontaneously in dogs. The reason for this apparently has to do with the way the canine stifle (knee) is put together.
There are two cruciate ligaments in the knee: the anterior (or cranial) and the posterior (or caudal). These ligaments cross within the knee joint, hence the name, "cruciate."
The positioning of these ligaments provides stability to the knee joint, preventing the femur and the tibia/fibula from sliding on each other.
A classic test for an anterior cruciate ligament injury in dogs is "cranial drawer sign," which checks for instability and abnormal sliding motion within the knee joint.
The most common scenario for dogs injuring their cruciate ligament is one that I have witnessed myself.
One summer, while my parents entrusted their dog, Norman, to my care, I sort-of ... broke him. It was an accident! I thought I'd be nice and throw the Kong for him outside in the yard. As is my usual experience, no good deed goes unpunished.
Norman, a big, silly labrador of the chocolate variety, was enraptured by the mere thought of playing fetch, even when faced with my pathetic, weak-armed throws. Norman, always optimistic, did not judge the thrower of the Kong.
Norman was in love with the Kong and would follow it over a cliff, if necessary. No, this story does not take place near a cliff. It takes place on a glorious, sunny day on a wide-open, flat lawn.
As I hurled the Kong as far as I could (which, sadly, wasn't very far at all) I watched as Norman took off in an all-out sprint.
There's nothing like watching a retriever doing his thing. And then, I watched in horror as his left knee did a funny sort of bend, and he let out a yelp. He ran back with the Kong in his mouth, using only his other three legs.
Grief has five stages: denial, anger, bargaining, depression and acceptance. I believe my exact words at that moment were, "NO! This is not happening! Norman, you jerk - why'd you have to do this on MY watch? C'mon, you can put it down, look, it doesn't hurt that bad, how about for a treat? I think I'm gonna cry. Well, I guess I'd better call Mom and Dad." (The naughty words from this passage have been edited out.)
I was pretty sure my parents were going to kill me. FYI: Hallmark doesn't make a card for, "Sorry I broke your dog." I had to make up for it by doing Norman's surgery myself.
There are some risk factors for dogs unexpectedly rupturing (tearing) their anterior cruciate ligaments, such as having a family history of this injury, obesity, and being out-of-shape, but that doesn't mean it can't occur in dogs with no apparent risk factors. It can happen in any age, breed, sex or size of dog.
I am freshly reminded of this since I spent several hours last Wednesday night at a continuing education meeting on this very topic.
Anterior cruciate ligament rupture happens to be THE most common injury to the canine knee joint, so many surgical techniques have been developed through the years. Interestingly, even after many scientific studies, not one technique stands out as "the best," though opinions can become heated amongst surgeons on the topic. The good news is that most techniques work pretty well. And yes, surgical correction is the best treatment for this condition.
Sherman, my sister's chocolate lab, tore his anterior cruciate ligament when he was just 2-years old. I was no where near him when it happened, thank goodness. As it turns out, the injury occurred during a play session with Westley, my parents' then 3-year-old golden retriever.
I'm not sure, but I don't think either dog was wearing protective pads or helmets. Not that it would have mattered, anyway.
A dog like Sherman that manages to tear his anterior cruciate ligament simply running in the yard, is apt to do it again on the opposite side - and the chances of that happening are as high as 70 percent while he's favoring his already sore leg.
And guess what - Sherman did just that about a year after his left knee was repaired. It's the cruciate curse - bummer.
The "drawer sign" test can be difficult to do in an awake patient in pain, so, many times we sedate the dog and perform radiographs (x-ray pictures) to check more carefully.
Although torn ligaments are difficult to detect on a radiograph, x-rays can help rule out other possibilities, like tiny fractures, arthritis and cancer. When dealing with a dog suddenly refusing to bear weight on a hind leg, it pays to be thorough. The anterior cruciate ligament in dogs is a fan-shaped structure, and even when only partially torn, can cause great discomfort to the dog without a detectable "drawer sign." Sherman was one of these cases.
Even when fully anesthetized, Sherman's stifle was stable and did not exhibit "drawer sign." However, following the laws of probability, as well as what my Dad refers to as my professional acumen, I decided to surgically explore his knee anyway.
Sherman's cruciate ligament was torn, but not all the way through - it was hanging on by about two threads. Fortunately for Sherman, the injury was very recent and very little arthritis had developed in the injured joint.
Although surgically invading a joint is guaranteed to induce inflammation and begin arthritic changes, with the proper stabilizing technique, medicines and post-surgical physical therapy exercises, most dogs have minimal discomfort.
That being said, contact sports are strictly forbidden once the dog has undergone surgery. I suggested to my sister that Sherman take up golf.
Seriously, swimming is an ideal sport for a dog like Sherman.
Unfortunately, unless Sherman joined the Y, I seriously doubt he's been swimming much while living in Buffalo, N.Y.
So, instead, it's long walks on the leash, which Sherman does enjoy.
Suffice it to say that although Sherman's Frisbee dog career never got started, it never will.
Mostly, that's because Sherman has never learned to catch anything in his mouth, and although he will chase a frisbee, he tends to then eat it, which is universally frowned upon in the frisbee-ing community.
And if you're ever lucky enough to watch a true frisbee dog in action, please don't even jokingly refer to the cruciate curse. Not funny.
Daverio is a veterinarian at Williamsport West Veterinary Hospital.