If you have a lame dog, don't ignore it - help is available
There was no need for me to ask his owner why Jimmy the Spaniel had been brought to the vet. It was obvious that he had a severe lameness: he was holding his back right leg in the air, refusing to put any weight on it.
Vets use a simple scale to classify the severity of a lameness. One-out-of-five describes a dog whose lameness can barely be noticed, whereas five-out-of-five means, like Jimmy, that the animal is not weight bearing at all on the affected leg.
When examining lame dogs, the challenge is always the same for vets: what, precisely, is causing the animal to be lame. An owner may have noticed that the dog's gait looks abnormal, but what's the underlying cause? It isn't always as easy as you might think to find this out. There are four main reasons for a dog to be lame.
As in humans, pain is the most common and important cause of lameness. If an animal dog injures a limb, any further pressure causes more pain, and so the instinctive response of the animal is to rest the limb, by holding it up, or by not putting full weight on it. The type of injury can vary widely from a bruise to a broken leg.
The damage can be anywhere in the limb, from the toe to the shoulder or hip, and the result is the same - a lame animal because of pain. One-off injuries are not the only cause of pain in the limbs: many long term conditions like arthritis or even cancer can cause considerable pain.
It can be difficult for vets to assess pain in dogs: animals cannot tell us "it's sore here". We need to use the primitive approach of poking and prodding, and gently flexing and extending joints, watching our patient all the time so that we can see when they flinch because of pain.
Sometimes we need to do this several times, to ensure that we have definitely found the sore bit. It's not always as easy as you might expect: animals can be good at covering up pain, and they can also pull away just because they're fed up with being poked rather than because the sore area has been accurately pinpointed.
The second cause of lameness in dogs is less well known to owners: instability. A limb needs to be stable and solid, like the leg of a chair, to carry a dog's weight. If the leg loses this stability, the dog cannot put full weight on the limb. A broken leg is the most obvious example: even if it was not painful, a dog could not put weight on the leg because of the instability.
Ligament damage is another common cause of instability in the limb: if the ligaments of the knee are torn, the entire leg becomes unstable. If the dog tries to put weight on the leg, the knee collapses, so the dog learns not to put any weight on the leg.
The third cause of lameness is stiffness. When a dog develops arthritis, the affected joint becomes swollen and gnarled - like an older person's arthritic finger joint. The swelling of the joint is due partly to new bone which grows around the arthritic joint as part of the disease process. This new bone acts like rust seizing up a metal hinge - it stops the smooth normal movement of the joint. An elbow joint may only be able to move through half of its normal range of movement.
The result of this new bone is that the joint is stiffer and less mobile than it should be - and this means that the animal is unable to use the limb in the normal way. Hips, shoulders and knees are also commonly affected in this way.
The final cause of lameness can be neurological: if the nerve supply to a leg is damaged, the animal cannot control the muscles properly, and lameness results.
So lameness can be caused by pain, instability, stiffness and nerve damage. What can be done to help lame animals?
The answer depends on the precise cause of the lameness: a broken leg or a torn ligament needs surgical repair to remove the instability, a leg that's painful due to arthritis needs daily pain relieving medication, a joint that's stiff may need medication as well as physiotherapy, and if nerve damage is causing the lameness, there are various ways of helping.
What about Jimmy the Spaniel? My examination showed me that his problem was due to ruptured cruciate ligaments in his knee: a combination of pain and instability. The answer for Jimmy was complex. First, he needed short term pain relief to ensure that he was comfortable.
Second, he needed a complicated orthopaedic operation on his knee, using metal implants to redesign the shape and angulation of his knee so that his leg was stable enough to bear weight again.
And third, he was given weekly injections to improve his general joint health, to lessen the chance of arthritis causing his knee joint to stiffen up in the coming months and years. When I saw Jimmy three months after his first visit to the vet, he was walking normally again.
If you have a lame dog, don't ignore it. Whether the cause is pain, instability, stiffness or nerve damage, help is available. Ask your vet for advice on the best way to relieve the problem.