Questions for Dr. S, The Toast’s valiant veterinary correspondent, can be left in the comments. To save time and space, please keep in mind that Dr. S will, 100% of the time, remind you that her information is meant to be educational and to serve as a supplement to regular medical care from a veterinarian who has had the pleasure of having your cat’s shiny white teeth sunk into his or her real hand.

So, my little rescue dog that we’ve had for about 3 months has been diagnosed with a luxating patella, and he walks with a funny little gimp in his back right leg. Like, 2 or 3 steps, then hop. Rinse, repeat. He only does this when we’re out on a walk, though, not while walking around at home. But the weird thing is, we had him for about 3 weeks before he started displaying these symptoms. Is a seemingly sudden onset of luxating patella weird? Or is there a chance it could be something else? 

Related: Our vet says that surgery isn’t a great option because it probably doesn’t hurt him, it’s not hampering his movement really, and it’s not even all that guaranteed to fix it. Second opinion?

First off, so everyone knows what we are talking about, I’m going to go into what’s happening in a dog with luxating patellas (cats can get this too.) Dogs (and cats, horses, cows, sheep, pigs, etc.) have pretty similar skeletons to our own. The proportions and orientations are different, but most of the bones are there. Even giraffes have the same number of cervical vertebrae (neck bones) as we do, they are just bigger and longer. So, dogs have knees on their hind limbs and the joint is set up pretty much like the human joint. The patella is located in a tendon that runs from the quadriceps to the tibial tuberosity (a bump on the front of the shin bone right below the knee joint). The patella is supposed to ride smoothly in a groove at the lower end of the femur (thigh bone) when the knee is flexed and extended. This is called the trochlear groove. In many small and medium breed dogs the structure of the back legs is what my orthopedics instructor would call “sub-optimal.” In some of these cases the trochlear groove is not deep enough to hold the patella in place. In others the location of the tibial tuberosity causes a general misalignment of the joint. Both of these situations cause the patella to slip out of the groove toward the inside of the leg. We grade these cases based on how difficult it is to slide the patella out of place, or, in the more severe cases, how hard it is to put it back in place. Even without a physical exam, your description of skipping or hopping in the back leg makes me feel very confident in your vet’s diagnosis, what I can’t say for sure is how severely his case would be graded.

The problem is, any time a joint is not functioning correctly there is a large amount of abnormal wear and tear on the joint. This is the same reason hip dysplasia and torn cruciate ligaments cause long term problems in dogs (and people.) In order for joints to function well, the articular cartilage needs to be smooth; when the kneecap slides in its groove, this works great. Each time your dog’s kneecap slips to the inside of his knee joint (causing the skipping step) there are abnormal stresses placed on the cartilage in the trochlear groove. These abnormal forces cause damage to the cartilage, and may cause it to become thinner and less resilient. Over time, this adds up to bones rubbing against each other and inflammation in the joint. In other words, arthritis.

My recommendation is to pursue surgery. Realigning the patella in the knee joint is the best way to slow the progression of arthritis by reducing the abnormal forces on the cartilage. With a good surgeon, I feel the likelihood of success is very high. There are a few different procedures that may be indicated based on the structure of each knee joint so it is possible that the procedure your dog needs is outside of the scope your veterinarian’s practice. Glucosamine, Chondroitin, and especially Omega-3 Fatty Acid supplementation is a good idea in any dog with extra stresses on the joints (working dogs, agility training, injury, or any “suboptimal” joint structure.) Both myself and my dog have had surgical procedures to fix luxating patellas (technically in humans it is subluxing patellas but the kneecap still slips out of its groove.) My dog had his surgery immediately upon diagnosis and this knee has the least amount of arthritis of all his joints now that he is in his geriatric years. I waited about 8 years after the onset of symptoms to have my knee problems addressed and I have significant joint disease in that knee (time to schedule knee surgery #3 in 10 years as soon as the snow melts.)

Can you give us some straight talk about tooth-brushing? I’m a pretty pragmatic cat-momma – growing up all my cats were outdoor cats who were all eventually and inevitably killed by fishers, except for one who had kitty leukemia and died of some combination of that and old age – so I tend to err on the side of thinking my (2, now indoor) cats are resilient, if lovable, little predators and I don’t worry too much about them unless something seems seriously wrong. But when we took our younger (boy) cat to the vet last, the vet told us that his teeth had a lot of plaque and we either needed to brush them with our fingers every day or plan on bringing the cat in to have his teeth cleaned pretty soon, which would involve them putting him under and would be expensive. And that yucky teeth can lead to kidney failure eventually.

Anyway, we tried toothbrushing, but we are busy people and it was really gross and stinky and the cat freaked out and it was a whole big thing, so eventually we got some of that stuff you can put in the drinking water to dissolve plaque and some treats that are supposed to help with teeth-cleaning and figured we’d see what happens when we bring him back next year. Is this, like, literally the worst attitude we could have? Was our vet just trying to scare us, or is this a serious and imminent danger? Does the water stuff actually help? (It’s been a few months, and he doesn’t have terrible bad breath or trouble eating or anything that would indicate horrible decay.) 

In the past couple of decades a lot has changed in veterinary medicine. Previously, we were much more focused on treating diseases as they came up and preventing infectious disease outbreaks with vaccination. The current focus in much of general practice veterinary medicine is now preventing disease and managing chronic disease states. Our pets are living a longer life than they did in the past, both cats and dogs. Part of this is due to the changing relationship between humans and animals and part of it is changing what we think of as routine preventive care. I believe that dental care should be part of routine wellness care for all dogs and cats. Some are going to need more interventions than others but they all deserve some level of preventive oral health care.

Let’s go over exactly what it is we are talking about in terms of a disease process. Plaque is a film of bacteria that forms over the teeth, this happens in everyone and is why we should all be brushing and flossing our teeth regularly. At the plaque stage, we can still easily break up the film of bacteria and brush it away. Once plaque is on the teeth for 24 hours it starts to mineralize, this is the process of turning into tartar or dental calculus. Tartar cannot be removed from the teeth by brushing. The surface of tartar is rough which encourages even more bacterial deposition, this is why when you go to the dentist they first scrape all the tartar off your teeth and then polish them so there are no rough spots to encourage faster plaque accumulation.  Plaque doesn’t just build up above the gumline.

When bacteria attaches and mineralizes below the gumline, the consequences are much more than bad breath and an unpleasant appearance. This accumulation of bacteria leads to gingivitis and periodontal disease. This means that the bacteria begin to break down the attachment of the teeth to the gums and eventually damage the bones that support the teeth. It is impossible to know what stage of disease is present simply by looking at your cat’s teeth while he is awake. The only way to know what is going on with the structures holding the teeth in place is by using a dental probe (just like your dentist) to assess the amount of space present around the teeth and sometimes taking radiographs (x-rays.) By the time the disease is bad enough to make your cat’s breath terrible or make him alter his eating it is too late to save the affected teeth. Cats and dogs are very good at hiding discomfort and illness but we know from people that the process of inflammation of the gums and loss of support for the teeth is very painful. Despite this, the biggest problem with periodontal disease isn’t what is going on in the mouth. When the gums become inflamed it is very easy for bacteria to cross into the bloodstream. Periodontal disease in dogs has a documented association with microscopic damage to the kidneys, liver, and heart.

So the short answer to your question: ideally you should be doing something to reduce the amount of plaque and subsequent tartar on your cat’s teeth at least once per day. The gold standard is brushing, but, that being said, I will freely admit that I do not brush my dogs’ teeth. I do try to use a product designed to reduce plaque and tartar (for them it is prescription chews and OTC dental treats) at least a few times per week and they both get at least yearly cleanings under anesthesia. I will recommend looking for the VOHC (Veterinary Oral Health Council) seal on any products being used to reduce the build up of plaque and tartar. In terms of exactly what products to use and how frequently I would suggest using them the answer is really it depends. I don’t make the same recommendations for the average Yorkie as I do for the average Pit, and cats are even more individual. This is something you need to talk to your vet about to get the appropriate recommendations. I am a big proponent of yearly cleanings for all adult pets. This is the only way to really know what is going on in your pet’s mouth (even my dogs won’t let me check for periodontal pockets without anesthesia.) If you have a pet with periodontal disease and another underlying health concern, you may have been told they can’t have their teeth cleaned. If it is possible for you I would suggest a second opinion (preferably from a referral or dental specialty practice.)