Most people have, at some point, met a pet with only three legs. The reasons for amputating animals’ limbs are as wide and varied as the reasons in humans.

Some pets develop tumours such as osteosarcomas, which sit in the bone and spread round the body. These can be painful and even when the tumour might have already spread, amputation may be the safest way to ensure future comfort. Other pets break their limbs and while most fractures can now be repaired, sometimes this is incredibly fiddly with a high risk of failure.

Sometimes, even when the risk is low, the financial cost of repair is too high. Less common reasons include skin wounds or infections which refuse to heal, or limbs with severe deformities which impede, rather than add to, the quality of life. 

Whatever the reason, this is a ‘salvage’ procedure, designed to keep the patient as happy and well as possible when the leg cannot longer be saved. The good news is, that such dogs and cats usually do very well. Pets can still have a great time with only three legs and can be thoroughly stable. Three legs carrying 4 legs’ load can ultimately lead to arthritis, however. For this reason it’s particularly important that such pets don’t get too fat. 

How do we amputate a forelimb?

You may know that a dog’s front legs are not actually attached to its trunk by the skeleton; the shoulder blades, scapulae (the top bones of the legs) are simply held in place by connective tissue and muscle. Thus the amputation of the whole forelimb doesn’t involve cutting any bone; the surgeon simply cuts through the shoulder muscles until the front leg comes free.

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But it’s not quite as simple as that. The muscles should be cut in such a way that they can be sewn back together again, keeping the line of the dog as smooth as it can be and the skin closed over the top. 

And a hindlimb​?

The hindlimbs, or pelvic limbs are firmly attached to the body by a ball-and-socket joint at the hip. Most frequently, instead of dislocating the hip, the vet cuts through the upper leg-bone (the femur). This is done with a saw, because more sudden methods might make it splinter. The bone is surrounded by thick muscles which are closed very carefully around the newly sawn ‘end’. This prevents the ‘end’ from rubbing on the inside of the animal’s skin; rather, a small bag of fluid (seroma) forms around the end of the bone within the muscle, protecting the sawn-off bone from causing damage when the pet runs. 

What then?

The skin has to be closed around the site of amputation. Inevitably, where bone has been taken away, a ‘gap’ is left and fluid may build up in its place. A ‘drain’ is sometimes used; a length of plasticky material that leads any fluid build-up away to the outside of the pet. There may be sutures (stitches) on the outside, or they may be all on the inside.

Most vets check the wound after a day or two and again a week or two down the time. Because the skin has had to be shaved for the operation, the pet can look very strange to start off with. However, once the fur has grown back, missing limbs can be surprisingly easy to overlook. 

The pet may require a collar or dressing at first, to stop them from licking or disturbing the wound. They also need pain relief because cutting through muscle and skin is generally quite sore. However, dogs and cats seem to adapt to having three legs very quickly and the outcomes of this procedure tend to be good. 

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You may also be interested in our post on whether amputation is fair. But please share your experiences and questions in the comments section below.