Pete Wedderburn
WHEN SALLY the Lurcher came in to see me, it was obvious that she was limping: her head nodded down every time she put weight on her right front leg. But her left back leg also seemed to be moving in an uneven way. So which leg was causing the problem?
I carried out a physical examination of Sally, and soon discovered that the source of her pain was her left front leg. She was lifting her body up when she walked on her left foreleg to avoid putting pressure on it, and this made her head dip down when she put weight on her right foreleg, which is why she was “nodding”. And her back left leg was moving oddly as part of the compensation process as her body tried to move her along evenly.
It can be difficult pinpointing which leg a dog is lame on, and even when this has been done, the diagnostic process has just begun. In Sally's case, I then had to work out which part of her left front leg was causing her to limp.
When a human is lame, or walking with a limp, the problem is usually caused by a problem with one of their two legs. With pets, the possibilities are doubled: instead of just two legs, animals have four. The forelegs are the equivalent of the human arms, but their function is completely different: they support the body rather than being used to operate tools and to carry out other tasks. The forelegs carry 60% of the weight of an animal's body, so they are under significant daily pressure. It's no wonder that many lamenesses of pets affect the forelegs rather than the hindlegs.
There are five main areas in the foreleg that can be the source of lameness: the shoulder, the elbow, the wrist (called the “carpus” in animals), the equivalent of the hand bones (called the “metacarpus) and the animal version of “fingers” (known as the “digits”). To find out which part of Sally's left foreleg was causing problems, I had to poke, twist and tweak each separate part of her left foreleg.
When I did this, I discovered where she was sore: it was the equivalent of her little finger, known in dogs as “digit number five”, colloquially described as her outermost toe. When I squeezed and poked this, Sally whined and pulled away from me.
I could tell by feeling the toe that it wasn't fractured, but there were still several possible causes. She had only been lame for one day, so it seemed likely that she might have just sprained it. Dogs like Sally tend to rush around the place at breakneck speed, throwing themselves around corners and putting major twisting and stretching stresses on their toes. Perhaps it's surprising that they don't sprain joints more often.
I gave Sally a simple initial treatment: a five day course of pain relieving anti-inflammatory medication, combined with strict rest. She made a prompt recovery, and two weeks later, she was rushing around, with her normal graceful, smooth gait, as if she'd never been injured.
There are many other possible causes of forelimb lameness. The simple “sprain” that Sally had suffered is the most common, with the digits, elbow or shoulder most commonly affected. Rest and time, combined with pain relief, are usually enough to solve these cases.
Dislocations - when one side of the joint becomes disconnected from the other side - are also seen occasionally: the shoulder and elbow are most common affected. Obviously, the lameness is sudden and dramatic: a rapid visit to the vet is needed, and with luck, the joint can be popped back into place under general anaesthesia. Fractures also cause dramatic lameness, and although a classical case of a broken leg has an obvious “hanging free” appearance, there are many types of fracture that are more subtle. X-rays is always needed, and the treatment approach depends on the details of the broken bone.
Bone tumours are another cause of forelimb lameness. In most cases, the lameness starts off as a mild limp, but it gets steadily worse with time, over days or weeks. An x-ray is
“Perhaps the most common cause of long term forelimb lameness in pets is arthritis”
needed to make the diagnosis, and in rare cases, a bone biopsy may need to taken to confirm what's happening. Surgery to remove the tumour usually means amputating the limb. In many cases, even this is not enough, because bone tumours tend to be malignant, spreading to elsewhere in the body.
Perhaps the most common cause of long term forelimb lameness in pets is arthritis, or as it's known these days, “degenerative joint disease”. This often follows developmental problems in a young growing dog: the joint surface of the elbow or shoulder can develop uneven patches that go on to be a focus for arthritis as the dog grows older. Treatment of such cases involves a patchwork of medication, physiotherapy and lifestyle management: a dog with advanced arthritis may need a ramp to get into a car, rather than being able to jump up as normal.
The final part of the forelimb to mention from a lameness perspective is the feet: dogs walk everywhere in their bare feet, so they are prone to standing on sharp or irritating objects. A careful inspection of every toe is an important part of any lameness investigation.
If your dog develops a lameness that doesn't get better after a few days' rest, a visit to your vet is needed: Sally was walking smoothly and comfortably within a couple of hours of her treatment starting.