Maya has always been a healthy dog, enjoying an active life with plenty of vigorous exercise. She suffered a minor lameness once, four years ago, but it turned out just to be a sprained toe, and it settled down promptly with some rest and pain relief.
Maya is an athletic creature, leaping with enthusiasm into the back of the car, onto the sofa or over any small obstacles in her path. This summer, Sharon had noticed that Maya was slowing down a little. She put it down to her increasing age. Perhaps it was normal for a middle aged dog to pause before taking a jump?
Then one day, when out on a walk, with no prior warning, Maya suddenly started to carry her left back leg. She didn’t yelp, there was no collision with anything, and she didn’t fall over or twist it. She just started carrying the leg in the air, refusing to put any weight on it.
At first Sharon thought that it might be something minor, like the sprained toe. She rested Maya for a day, to see if she’d start to walk properly again. When there was no improvement Sharon called my clinic for an appointment.
There’s a standard routine that vets go through when examining a lame dog. Unlike doctors, we can’t ask our patients where they are feeling sore. We need to poke, prod and twist their limbs to pinpoint the focus of any discomfort. Most animals are surprisingly tolerant of our attention as we do this. Maya stood on the consultation table, gently wagging her tail. Sharon talked to her, reassuring her, while I examined her back left leg in detail.
She didn’t flinch while I squeezed, flexed and extended her toes, or her ankle, and she didn’t mind when I stretched out her hip backwards and to either side. But when I tried to straighten her knee, she yelped and looked uncomfortable. Her knee felt hot and swollen too. This was definitely the focus of her problem. But what, precisely, had gone wrong with her knee?
If she was a human, she would have been sent straight away for an x-ray, but it’s different for animals. They can’t be expected to stay still for x-rays, holding their body in the right position for a clear view. Sedation or anaesthesia is needed, meaning that fasting is usually necessary before xrays are taken. So at that first visit, I gave Maya some pain relief and booked her in for x-rays the following morning.
Maya is an easy-going dog, and simple sedation was enough to allow us to take the x-rays. She lay on her side, snoozing, while I took different views to look for abnormalities in her knee. While she was lying there relaxed, I examined her knee in more detail: it had been too sore to do this the previous day. The xrays showed that there was no bone damage, and my detailed physical examination her knee confirmed the diagnosis: she had suffered rupture of her cruciate ligaments, a common problem in middle aged large breeds of dog.
The cruciate ligaments are bands of fibrous tissue that link the two opposite sides of the knee joint, extending from the far end of the femur (thigh bone) to the near end of the tibia (shin bone). The ligaments keep the opposing surfaces of the knee joint in close, steady contact with one another. When they rupture, it’s the equivalent of a broken door hinge: the two sides of the knee joint are no long held in a stable position. The knee wobbles when the dog tries to place weight on it, and it’s painful.
Cruciate rupture happens in humans following sudden twists to the knee (it’s common in footballers) but in dogs, it generally happens spontaneously, as in Maya’s case. The ligaments degenerate with age, like rubber bands perishing, and rupture happens without any specific fall or other incident.
In large animals like Maya, there’s just one possible treatment option: surgery to repair the damaged knee. Without this, Maya would never be able to walk on her left back leg again. The operation was scheduled at my clinic for the following week.
Cruciate surgery is a specialised skill: one of my colleagues at Brayvet, Andrew Byrne, has a special interest in this topic. He carries out several “cruciate operations” every week, doing these for our own patients as well as treating cases that are sent to us from other vets.
There are a number of possible techniques, with the best option depending on the specific details of the animal. In Maya’s case, a new technique known as Tibial Tuberosity Advancement was used. This involves cutting the top of the shin bone (the tibia), moving it forwards and stabilising it in a new position using a specially designed titanium implant. This procedure rearranges the geometry of the knee, allowing the dog to bear weight normally again. It’s a major operation, but it’s usually very successful.
Maya’s operation went well. She went home the same evening, and by the next morning, she had already begun to put weight on her left back leg.
It’s now just three weeks since the surgery, and she’s walking normally. The biggest challenge for Sharon is to keep her quiet: Maya is meant to take it easy for a month after the surgery, but she doesn’t understand. She just wants to get back to her normal running, jumping and leaping lifestyle!