If you’ve ever seen a footy player go down on the field clutching their knee in agony, you’ll know that knee injuries can be painful and debilitating. The same is true for dogs and cats – especially when it comes to a dislocated kneecap, also known as patellar luxation. But unlike in humans, in dogs and cats, dislocated kneecaps are more likely to be caused by genetic factors than an injury.
If your pet has been diagnosed with patellar luxation, they might need surgery to put their kneecap back in the correct position. Here’s everything you need to know about patellar luxation surgery for dogs and cats, so you can help your furry mate get back on all four paws as fast as possible.
What is patellar luxation?
Patellar luxation is much more common in dogs, but it can also affect cats – particularly younger, active cats or those with underlying skeletal issues.
First, a quick anatomy lesson. Dogs and cats both have two kneecaps (patellas), one on each of their back legs, which sit in a groove at the end of the femur. Fun fact – the joints on the front legs are called elbows. If the kneecap slides sideways or pops out of that groove, it’s called a luxating patellar – ‘luxating’ simply means ‘out of place’.
There are two main types of luxating patellars:
- Medial patellar luxation (MPL) is the most common and happens when the kneecap moves towards the inside of the knee. In around 50% of MPL cases in dogs, both kneecaps are affected. This condition is also the most common form of patellar luxation seen in both dogs and cats.
- Lateral patellar luxation (LPL), where the kneecap moves towards the outside of the knee, is less common in both species but can occur – especially in larger dog breeds or cats with underlying musculoskeletal issues.
What causes patellar luxation?
Sometimes patellar luxation is caused by an injury – a slip, tumble or awkward landing. But most of the time, it’s something your pet is born with or develops as they grow and mature.
In dogs, it’s often linked to genetics. Breeds like chihuahuas, Maltese, pugs, terriers, toy poodles and dachshunds are top of the list, but in recent years vets have also seen more cases in big breeds like Great Danes, Irish wolfhounds and Saint Bernards.
Cats aren’t off the hook either. Patellar luxation is less common in felines, but it does turn up – especially in breeds like the Abyssinian and Devon Rex. In cats, it can be inherited or show up after an injury or joint problem.
What are the signs of patellar luxation?
In mild cases of patellar luxation there might be no signs at all – it might be something your vet happens to pick up on a routine visit. But if patellar luxation is more severe, you might notice your dog doing a ‘skip’ – lifting one of their back legs off the ground briefly while walking or running, then shaking the leg and returning to normal movement – a bit like when your own foot has gone to sleep. Other signs of MPL include:
- A cracking or popping noise when your dog bends their knee
- A yelp while skipping
- Hunched lower back
- Bow-leggedness.
Patellar luxation signs can come or go, but that doesn’t mean the problem has sorted itself out. Without treatment, patellar luxation will unfortunately become more severe over time, and can progress to worsening lameness, arthritis and torn cruciate ligaments.
How is patellar luxation diagnosed?
Usually vets diagnose patellar luxation through a physical examination but they might use X-rays, CT scans or MRIs for confirmation. Your dog will be given a MPL ‘grade’:
- Grade one – this is where the kneecap is more mobile compared to normal, but does not fully dislocate from the groove unless the knee is fully extended.
- Grade two – the kneecap slips out of place occasionally but will return to the groove in which in sits.
- Grade three – like grade two, but where dislocation is happening most of the time. The kneecap can be replaced into the groove, but will immediately dislocate again.
- Grade four – the most severe MPL grade, when the patellar is permanently out of its correct position and can’t be moved back into the groove even with manipulation.
How is patellar luxation treated?
Treatment depends on how serious the problem is. If your dog or cat has a mild case (known as grade one or in some grade two cases), surgery usually isn’t needed. Instead, your vet might recommend:
- anti-inflammatory and pain medications
- joint supplements
- temporary exercise restrictions
- rehabilitation exercises including hydrotherapy and physiotherapy
- a weight-loss regimen (to help lower the chances of your pet developing arthritis).
What happens in patellar stabilisation surgery?
If your pet has a more advanced case (grade two cases that have recurrent or severe bouts of lameness, or grades three and four), surgery is often the best option to restore comfort and mobility. While under anaesthetic, the kneecap is moved back into the right position, the groove in the thigh bone (femur) is deepened, and soft tissue around the joint is tightened for extra support.
Kneecap surgery has a high success rate, especially in pets that haven’t yet developed arthritis. In fact, one small study showed a 93% success rate for grade four surgeries in dogs.
Even if surgery isn’t needed, being diagnosed with MPL means your pet is more likely to develop arthritis later on. You can help reduce the risk by keeping them at a healthy weight, using joint supplements if recommended, and sticking to an exercise plan that suits their needs.
How can I help my pet recover from patellar luxation surgery?
Recovery from patellar luxation surgery usually takes at least eight weeks, and your pet will need to take it slow during that time. That means no running, jumping or zooming around – even if they seem up for it. It might be frustrating (for both of you), but limiting movement is the best way to support proper healing.
Your vet may recommend crate rest and will likely provide a rehabilitation plan tailored to your pet. This could include gentle physio, controlled walks or hydrotherapy. Once X-rays are repeated to confirm that the bone has healed, you’ll be able to gradually return your pet to full activity.
The recovery process takes time, but it’s worth it. With the right care, most dogs and cats bounce back well – returning to a more active, pain-free life. If you’re unsure about anything, ask your vet – they’re there to help you both through it.
Worried about your pet’s knees?
Worried about your pet’s knees?
If your dog or cat is skipping steps, limping or showing signs of discomfort, it’s a good idea to schedule a check-up with your local vet. Whether it’s joint supplements, rehab or surgery, there are ways to help your furry mate move comfortably again.
