Junior, a twelve year old Japanese Spitz dog who stopped putting weight on his left hind leg.

Junior’s an older dog now, at twelve years of age, but he’s still a quick-moving, nimble creature, trotting around the place rather than walking. His recent problem started in the winter months. All of a sudden, he started to carry his left back leg, hopping around on three legs. When he tried to go upstairs, he wasn’t able to manage the staircase, and Eric had to carry him.

At first, Eric thought that he might be having tweaks from arthritis, a common problem of old dogs. The weather had been cold, and Eric wondered if this could be aggravating his joints. Junior was a bit better the next day, but he never quite returned to normal, continuing to carry his leg from time to time. When he had still not made a full recovery a month later, Eric brought him to see me.

As a vet, the first thing to do with a lame dog is to identify the precise location of the problem. Lameness can be caused by pain, by damage to nerves, and by unstable joints. A careful physical examination is the best way of sorting out which of these is causing the lameness.

I started at Junior’s toes, and worked up his body to his hip, twisting and tweaking each joint. Junior didn’t mind me doing this at all, so I knew that his lameness was not caused by pain. I then checked his reflexes, and they were all normal, confirming that it wasn’t caused by a neurological problem such as a “trapped nerve”. Finally, I tested the stability of his leg, by putting firm pressure across each joint, with one hand below it and one above.

It was only when I did this last test that I discovered the cause of the lameness. Junior’s left knee was unstable, wobbling around far more that it ought to do. To confirm the precise cause, Junior was booked in the following day for xrays and a detailed examination under general anaesthesia.

These extra tests confirmed what I had suspected; Junior had ruptured his cruciate ligaments. This injury is often seen in older dogs, and it’s the same problem that’s so common in human footballers. The cruciate ligaments support the bones of the knee, holding them snugly together. The ligaments degenerate with age in some animals, like a frayed piece of string, so that a relatively small twist of the knee can be enough to cause the ligaments to rupture. Once they’ve  ruptured, the knee becomes wobbly and unstable, so that the leg is no longer able to bear weight.

The ideal way of correcting a ruptured cruciate ligament is surgery.  A skilled surgeon can insert a replacement ligament and stabilise the joint so it functions normally again. If the surgery is not done in large dogs, irreversible arthritic changes start to develop and the dog is permanently lame.

The surgery is not cheap, so it was a relief to Eric to hear that for smaller dogs (less than 15kg), a less expensive choice is an option. Simple rest and time, combined with anti-inflammatory medication, can work effectively in around 80% of smaller dogs. The 20% that do not respond well, unfortunately, do often need surgery, and the sooner this is done the better.

Junior is now resting, only going out for short walks, on the lead. We’re all hoping that within a couple of months, his ligaments will have healed naturally. And if not, it may be that the joint surgery will become necessary. Whatever happens, as soon as he’s allowed to do so, Junior’s looking forward to his walks resuming.

Tips

• Cruciate ligament rupture is a common problem in older dogs
• Small dogs sometimes respond to simple rest, time and medication
• Larger dogs always need complex surgery to cure the lameness