Luxating patella in dogs

Overview

  • Does your dog occasionally hold a back leg up and hop along for a few seconds? If so, they may be suffering from patella luxation.
  • ‘Patella’ is the scientific name for the kneecap, and ‘patella luxation’ simply means ‘dislocating kneecap’.
  • Although patella luxation can affect any breed of dog, it is most common in toy and small breeds.
  • Some dogs with mild patella luxation don’t need any treatment, but some dogs, with more serious problems often need physiotherapy and/or surgery.
  • Patella luxation can affect one or both knees, and can lead to arthritis.

What is a luxating patella?

When a healthy knee bends, the kneecap slides up and down a groove in the thighbone. A healthy kneecap should never slip out of the groove, and if it does, we call it a luxating patella (dislocating kneecap). When the kneecap dislocates, it stops the knee from bending, causes a limp and rubs past the bone as it slips, which over time, can cause pain and arthritis.

Patella luxation can affect one or both knees, and varies from grade 1 to grade 4:

Grade 1:  The kneecap is loose, but stays in the correct place when your dog moves around. It will dislocate if forced by your vet, but immediately returns when released. Grade 1 patella luxation doesn’t often cause much of a problem.

Grade 2:  The kneecap occasionally dislocates when your dog moves around, but usually returns by itself. Grade 2 symptoms range from mild to moderate depending how regularly the kneecap dislocates.

Grade 3:  The kneecap is permanently dislocated, can be pushed back into place by your vet, but slips straight out again when they let go.

Grade 4:  The kneecap is permanently dislocated and is impossible to push back into place.

An illustration of a luxating patella (click to enlarge)

Symptoms

Although symptoms of patella luxation can appear at any time, they often to develop before one year of age. Symptoms include:

Intermittent hopping/ skipping

This usually lasts for a few seconds (until the kneecap has slipped back again)

Stiffness

  • Stiffness can affect one or both back legs
  • Ranges from mild to severe.

When to contact your vet

Contact your vet for an appointment if you suspect your dog may have patella luxation. The sooner it’s treated, the better your dog’s outlook, and the less chance of arthritis in the future.

It’s really helpful for your vet to see your dog limping, so if possible, take a video of your dog to show your vet.

Diagnosis

Your vet will very carefully feel your dog’s knee and perform a few different tests to check the stability of the kneecap. They will also check your dog’s cruciate ligaments because cruciate disease is common in dogs with patella luxation. Some dogs need a general anaesthetic and x-rays for a full diagnosis, especially if their knee if very painful.  

Treatment

The treatment your dog needs will depend on the grade of their patella luxation and their symptoms. If your dog only limps every now and again (perhaps every few weeks), it might be possible to manage their patella luxation with physiotherapy and exercise control. However, if your dog limps regularly or is in pain, surgery might be the best option.

Physiotherapy and exercise control. Most mild cases of patella luxation (grade 1&2), can be managed without surgery. Physiotherapy and controlled exercise can be used to build-up the leg muscles and stop the kneecap slipping.

Surgery. Surgery is necessary for some dogs with patella luxation, especially if it is severe (grade 3&4). There are a few different surgical options, and your vet will help you decide which is the best for your dog. It’s important to be aware that all surgeries have pros and cons, and some of the more complex patella procedures can only be performed by a specialist vet, at a referral centre.

Pain relief. Most dogs with patella luxation (with the exception of some grade 1’s), experience pain at some point during their life. Your vet will be able to prescribe pain relief such as NSAID's to give as necessary.

Post-surgery advice

After your dog has had surgery, they will be sleepy and probably a bit sore for about 24-48hrs. They will need strong pain relief, close monitoring and very importantly a quiet, calm place to rest (ideally in a crate, so they can’t walk around).

Once your dog has recovered from their anaesthetic, they will need strict rest for at least six to eight weeks (while their bones heal), before very gradually returning to exercise. Your vet will give you a recovery plan detailing how much rest, exercise, pain relief and physiotherapy your dog needs during their recovery. It’s important to follow this plan exactly, and to contact your vet if you hit any problems, or are unsure about any of the steps.

Outlook

Dogs with grade 1 patella luxation usually don’t often show symptoms or require treatment. However, they should be monitored to make sure their symptoms don’t get any worse.

Dogs with grade 2 patella luxation, that are managed carefully with the correct treatment, often do extremely well and are able to live a happy, pain-free life.

Most dogs with grade 3-4 patella luxation do well if they have corrective surgery. Unfortunately, without surgery, dogs with a high-grade patella luxation tend to surfer with problems and pain throughout life.

It’s important to be aware that even with treatment, most dogs with patella luxation develop arthritis  in their knees later in life. Your vet will tell you what symptoms to look out for.

Aftercare

Weight. Keeping your dog at the correct body weight reduces pressure on their joints, which can help with patella luxation and arthritis in the future. Check your dog's weight and body condition regularly, and make sure you feed them the right amount to keep them at a healthy weight.

Sensible exercise. Once your dog has recovered, they will be able to exercise more or less normally. To minimise the risk of further injury, it’s best to avoid strenuous activities such as chasing, jumping and running up and down stairs/on uneven ground.

Supportive therapy. Your vet might recommend hydrotherapy or physiotherapy to help with your dog’s ongoing recovery.

Breeds and prevention

Patella luxation is more common in certain breeds, especially toy and small breeds. This is often because these breeds have bow-shaped legs or a shallow knee groove that doesn’t hold the kneecap in place. The best way to prevent patella luxation is to avoid breeding from any dog that has had a kneecap problem  in the past. If you are thinking of getting a dog make sure you research the breed thoroughly, and get the healthiest dog possible.

Breeds prone to patella luxation include:

Cost

As a general rule, the higher the grade luxation, the more complex and expensive the treatment. Costs tend to be highest if major, specialist knee surgery is required.  It’s very important to speak openly to your vet about your finances, the cost of treatment, as well as what you think is right for your dog. There is often more than one treatment option, so if one doesn’t work for you and your dog then your vet may be able to offer another.

Consider insuring your dog as soon as you get them, before any signs of illness start. This will ensure you have all the support you need to care for them throughout their life.

Published: July 2020

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Written by vets and vet nurses. This advice is for UK pets only.

Illustrations by Samantha Elmhurst