Luxating Patella in Boston Terriers: Complete Guide (Statistics)

Did you know as many as 1 in 20 Boston Terriers may have luxating patellas?

A luxating patella is essentially when the kneecap pops in and out of place. They can range from mild luxations that cause no obvious symptoms to severe luxations that cause constant limping.

Luxating Patella in Boston Terriers: Complete Guide (Statistics)

This complete guide to Boston Terrier patella luxation will discuss everything you may need to know about this common condition.

A Complete Guide to Boston Terrier Luxating Patella

Boston Terriers seem to be more prone than many other dog breeds to developing luxating patellas. It is estimated that around 5 percent of Boston Terriers have a luxating patella.

In this article, you will learn what exactly a luxating patella is, symptoms to watch out for, how this common condition is diagnosed, and various treatment options available.

Luxating Patella in Boston Terriers: Complete Guide (Statistics)

What Is Patellar Luxation?

The patella is essentially your dog’s kneecap. The kneecap is normally stable and stays in position over the top of the knee. When the patella luxates, this means that the kneecap is popping in and out of place when it shouldn’t be.

Patella luxation or luxating patella are the medical terms for the kneecap sliding in and out of place abnormally. This could also be considered knee cap dislocation. Patella luxation can occur on one or both hind legs and can cause limping.

According to the American College of Veterinary Surgeons, luxating patella is an extremely common orthopedic condition seen in dogs. They estimate that around 7% of puppies are diagnosed with luxating patellas.

Patella luxation is more common in female dogs and is most commonly diagnosed in young animals. Some dogs may be diagnosed later in life. Sometimes, luxating patella is diagnosed in an apparently normal dog during a routine physical examination at the vet.

Interested in Boston Terrier health issues? Read this article, 10 Common Boston Terrier Health Concerns.

Video – Explanation Of A Luxating Patella Is With Demonstration

In this video, Dr. Owen Fink explains patellar luxation with a dog knee model.

Video – Dr. Owen Fink explains patellar luxation with a dog knee model.

Patellar Luxation Grading (How Severe Is It?)

Veterinarians grade patellar luxation on a scale of 1 to 4. Grade 1 is the mildest form of luxating patella, and Grade 4 is the most severe form. Dogs with higher grade patella luxation may be more predisposed to developing limping, pain, and arthritis.

Grade 1 Luxating Patella

For a Grade I patellar luxation in dogs, the kneecap only rarely pops in and out of place.

The knee can be manually popped out of place when the knee is stretched out. This means the vet can pop the knee cap out of place when the leg is extended. When the leg is flexed, the kneecap will quickly return to its normal position.

Dogs with Grade I luxating patella will usually have little to no symptoms. Surgical treatment is not recommended for this grade.

Grade 2 Luxating Patella

Grade II patellar luxation in dogs occurs when the kneecap begins to pop in and out of place more frequently when the knee is flexed. The kneecap will usually return to its normal position when your dog stretches out its leg.

This grade can cause intermittent limping or skipping. In addition, this grade can be painful especially if arthritis develops in the knee. Veterinarians may recommend surgical correction for this grade.

Grade 3 Luxating Patella

In Grade III patellar luxation, the kneecap is always out of place. This is a more severe form of luxating patella. A veterinarian will feel that the kneecap is out of place. They will be able to temporarily manually shift the kneecap back into position, but it will pop out of place again quickly.

With Grade III patellar luxation, you will often notice your dog limping or skipping. You may hear or feel popping in the knee. Surgery is recommended for this grade.

Grade 4 Luxating Patella

This is the most severe form of patella luxation in dogs. In Grade IV patellar luxation, the kneecap is always popped out of place and can’t be put back into position.

Grade IV patellar luxations in dogs require surgery because this form is the most severe and can lead to severe and painful arthritis if not surgically repaired. Usually, dogs with this grade of luxation will limp all the time.

Luxating Patella in Boston Terriers: Complete Guide (Statistics)

What Are The Symptoms Of Patella Luxation?

Some dogs with Grade 1 luxating patella may have no symptoms at all. You may not even know that there is an issue until your veterinarian diagnoses it.

If your Boston has a Grade 2 or 3 luxating patella, they may occasionally limp on one of both of their back legs. You may even feel or hear a popping sound within your dog’s knee. Grade 4 patellar luxation in dogs can cause severe and constant limping.

Here is a list of the most common symptoms of patella luxation that you may notice in your Boston Terrier:

  • Intermittent Skipping
  • Stretching Out The Bag Leg Or Shaking The Leg
  • Limping In One Or Both Back Legs
  • Bow-Legged Appearance To The Legs
  • Running On Three Legs

Is Patella Luxation Painful For Boston Terriers?

In the beginning, patella luxation may not be very painful. For Grade 1 patella luxations, you may not notice any sign of pain or limping. If the luxation progresses to a higher stage, it can become painful.

In addition, the luxating patella can predispose your dog to develop painful arthritis. Dogs with luxating patella are also more prone to developing torn ACLs in the affected legs. Torn ACLs are extremely painful.

Luxating Patella in Boston Terriers: Complete Guide (Statistics)

What Causes Patellar Luxation In Boston Terriers? Is It Hereditary?

Multiple factors can cause luxating patella including genetic abnormalities and traumatic injury.

Some luxating patellas are caused by trauma, but most luxating patellas are genetically acquired. There is evidence that patella luxation in dogs is genetic. It does appear to be hereditary, and it is therefore recommended that dogs with luxating patellas not be bred.

There is a groove on the knee that the kneecap sits within called the femoral groove. In Boston Terriers with luxating patella, this groove tends to be too shallow which allows the kneecap to slide out of position. 

In addition, some Bostons with luxating patellas have tendons that are abnormally positioned which may tend to pull the kneecap out of place.

If you want to learn more about health issues related to the Boston breed be sure to check out this article here on the Boston Terrier Society covering ten of the most common health issues. Click here, Common Boston Terrier Health Issues.

Video – Boston Terrier Patella Luxation

In this video, Donnie Gardner with the Boston Terrier Society interviews Dr. Addie Reinhard about Patella Luxation in Boston Terriers.

Video – Dr. Reinhard Explaining Patella Luxation In Bostons

How Common Is Patella Luxation In Boston Terriers?

Boston Terriers seem to be more prone to developing patella luxation than many other dog breeds. One study found that Boston Terriers may be around twice as likely to develop luxating patella than other dog breeds.

The Orthopedic Foundation for Animals reported that Boston Terriers were in the top 40 breeds with the highest prevalence of patella luxation. They reported that around 5.1% of Boston Terriers that they tested had luxating patellas.

Here is a graph with a comparison of the prevalence of patellar luxation in a few common dog breeds from data obtained from the OFA.

Figure 1. Prevalence of Luxating Patella in Common Dog Breeds

What Dog Breeds Most Often Suffer From Patella Luxation?

Small breed dogs like Pomeranians and Yorkies are most likely to be affected with patellar luxation. Some large breed dogs also have a predisposition to developing patellar luxation including the Great Pyrenees and the Akita.

According to veterinary researchers and the American College of Veterinary Surgeons, here is a list of the dog breeds that may have a higher risk of developing luxating patella:

Is There A Test A Vet Can Do To See If My Boston Terrier Has Patella Luxation?

To diagnose luxating patella, a veterinarian will feel your Boston’s knee and manipulate the kneecap. They will place gentle pressure on the patella to see if it is stable or unstable.

If your Boston has a luxating patella, when the veterinarian pushes on the kneecap, it will pop out of place. If your dog does not have a luxating patella, the knee cap will remain in the normal position.

Additional tests may be needed to ensure there aren’t any other orthopedic problems. Your veterinarian may recommend x-rays to check for hip dysplasia and blood tests prior to surgery or administering pain medication.

Do you want to save 25% at your next veterinarian visit? Check out Pet Assure. This health savings plan can save you 25% with no pre-existing conditions exclusions. See if your vet participates and pricing here at Pet Assure.

Luxating Patella in Boston Terriers: Complete Guide (Statistics)

Can A Puppy Outgrow Patella Luxation?

There are some issues that puppies might outgrow, but luxating patellas is usually not one of them. Once your puppy has been diagnosed with luxating patella, it will likely have it for the rest of its life.

Treating Boston Terrier Patella Luxation

If your Boston has been diagnosed with a patella luxation by the vet but it is not causing your dog any symptoms, it may be okay to just monitor the knee. Any time your dog has symptoms or a Grade 2 patella luxation or higher, surgery will likely be the best option.

Medical Management For Patella Luxation

Dogs with a Grade 1 patellar luxation can often just be managed medically. I usually recommend dogs with low-grade luxating patella with no symptoms to go ahead and start a joint supplement and a daily fatty acid supplement. These products may help decrease and manage arthritis.

I also recommend monitoring your Boston with a Grade 1 patella luxation, and if symptoms appear, visit a veterinarian.

In addition, maintaining ideal body weight is key for dogs with luxating patellas. This will decrease the strain on the knee and reduce the risk of complications from the luxating patella including torn ACL or arthritis.

Will Patella Luxation Correct Itself? Or Will It Get Worse Over Time?

In the beginning, especially with a lower grade luxating patella, the kneecap may pop back into place on its own. If the patella has luxated out of place once, the chances are this will continue to occur.

Once the patella has luxated, even if the patella returns to its normal position, there is now a high probability that it will continue to pop back in and out of place especially when your dog is exercising.

Some dogs with Grade 1 patella luxation will never progress to a worse grade. Other times, the patella luxation can get much worse over time and progress to a higher grade. 

Luxating Patella in Boston Terriers: Complete Guide (Statistics)

What Does The Procedure For The Patella Luxation Look Like? What Is The Process?

Surgery is usually recommended for any Boston Terrier that is having symptoms from their luxating patella or Bostons with Grade 2 or higher luxating patellas. The goal of surgery is to restore the kneecap into its normal position and keep it secured there.

Multiple procedures can be performed to repair patella luxation in dogs. Usually, veterinary surgeons will do a combination of techniques to ensure the best surgical outcomes.

The procedure is a fairly lengthy one that lasts around 1 to 2 hours. Your dog will need to be placed under general anesthesia for the procedure to be performed. This means your pet will be intubated and given sedative drugs and pain medications.

The surgeon will typically deepen the femoral groove (trochleoplasty) where the kneecap sits so it will have a decreased likelihood of popping out of place. They may also realign the bones around the knee (tibial tuberosity transposition) and reconstruct the tissue around the patella (lateral imbrication).

After the procedure, many vets will want you to leave your Boston at the veterinary hospital for several days to ensure that the pain is well controlled before sending your dog home.

Luxating Patella in Boston Terriers: Complete Guide (Statistics)

Can You Operate On Both Legs At Once For A Dog With Luxating Patella?

Whether or not your dog has both knees repaired at the same time is up to your veterinary surgeon’s preference. Many surgeons prefer only to treat one leg at a time so your dog can more easily adapt and recover.

Usually, I recommended getting the more symptomatic leg treated first. That means if your dog has been limping more frequently on one side, I would recommend getting that knee fixed first.

Some surgeons may choose to operate on both knees at once so your dog will not have to go through two separate anesthesias and surgeries.

What Is The Success Rate Of The Surgery For Luxating Patella In Dogs?

Surgery is typically very successful for treating luxating patellas, especially in small breed dogs like Boston Terriers. 

The American College of Veterinary Surgeons reported that over 90% of dog owners are happy with their dogs’ progress after surgery.

The success rate is very high if you strictly follow your veterinarian’s advice, including recovery instructions and adequate rest time.

The sooner the surgery is performed, the better. If you wait too long to get the surgery done, irreversible arthritis could develop in the knee leading to long-term pain and stiffness in the leg. It is best to get the surgery done as soon as your veterinarian recommends it.

Are There Any Complications That May Occur After Surgery?

A knee with luxating patella is never going to be a normal knee. 

While surgery helps repair the knee to close to normal function, there will always be some arthritis in the knee no matter what we as veterinarians do. This is why I recommend joint supplements and fatty acids after surgery. I usually recommend giving these supplements for the rest of your dog’s life. 

Also, dogs that have had knee surgery may develop infections, so it is essential to monitor for signs of infection around the incision, including foul odor, swelling, and discharge.

One of the most severe post-op complications can be a failure of the surgery. This can occur if your dog is not rested strictly enough after surgery or if your dog returns to routine exercise too quickly.

What Does The Recovery Process For Patella Luxation Look Like?

After surgery, the recovery process for patella luxation is long and involves strict rest, monitoring the incision, medications, and physical therapy as directed by your veterinarian.

See more about strict rest, monitoring incision, medications, and physical therapy below.

Strict Rest

The recovery period post-op for patella luxation is lengthy. After your Boston has had surgery, they will need strict crate rest for 8 weeks or as directed by your veterinarian. 

Strict crate rest means your pet must always be in their crate, except when walked to go to the bathroom. Make sure your dog is on a leash. Your dog should also be carried up and downstairs and should not be allowed to run or jump.

You will not be able to let your dog run off-leash or go on walks until after the 8 week rest period. Your vet will likely recommend a slow re-introduction to exercise. Normal activity can often be resumed at around 4 months post-op.

Although your pet may act like they are feeling better and may not be limping, it is important to follow your vet’s recommendations on the length of strict rest. If your Boston returns to normal activity prior to healing, this could damage the knee.

Luxating Patella in Boston Terriers: Complete Guide (Statistics)

Monitor Incision

You will need to look at your pet’s incision once or twice daily to monitor for signs of infection for 2 to 3 weeks post-op. You should take your dog to the vet right away to have the incision re-checked if you notice any of the following symptoms:

  • Excessive Swelling Around The Incision
  • Discharge Coming Out Of The Incision
  • Foul Odor Of The Incision Or The Discharge
  • Excessive Redness

Your Boston will need to wear an E-collar for a few weeks at all times so they do not lick the incision open. If your dog licks the incision open, this can delay healing and introduce bacteria into the knee which could result in an infection.


After the luxating patella surgery, your vet will likely place your dog on pain medications and joint supplements to help improve recovery times.

Physical Therapy

Some veterinarians will recommend physical therapy exercises for post-op recovery of patellar luxation that you can do at your home. In addition, some veterinary hospitals have certified canine rehabilitators that can help your dog recover.

Some of the exercises include passive range of motion exercises and stretches, which help keep the joints and ligaments from becoming too stiff after surgery.

Luxating Patella in Boston Terriers: Complete Guide (Statistics)

How Much Does The Surgery For Patellar Luxation Cost?

The cost of patellar luxation surgery depends on your location. This procedure can cost anywhere from $1,000.00 – $3,000.00 on average per knee. 

The price may be higher if a veterinary surgeon specialist is performing the procedure, but dog surgery specialists may be more experienced and have more training to perform this procedure.

Do you want to save 25% at your next veterinarian visit? Check out Pet Assure. This health savings plan can save you 25% with no pre-existing conditions exclusions. See if your vet participates and if this will save you on patella surgery pricing here at Pet Assure.

Are There Supplements A Boston Terrier Can Take To Help With Patella Luxation?

I usually recommend that any dog diagnosed with an orthopedic condition be started on a joint supplement and fatty acid supplement. These products won’t treat a luxating patella, but they can help with secondary arthritis associated with the luxating patella.

Joint Supplements

Joint supplements usually contain a combination of glucosamine, chondroitin, and MSM which may help slow the progression of arthritis.

I usually start Boston Terriers with luxating patellas on one of the following joint supplements:

Fatty Acid Supplements

Fatty acids for dogs are also used commonly in dogs with orthopedic conditions and may help decrease inflammation.

I usually start Bostons who have been diagnosed with luxating patellas on one of the following daily fatty acid supplements:

Should Someone Massage The Patella Back Into Place? How Do You Do It If So?

It is not recommended that a pet owner massage the patella back into place because you could potentially hurt your dog or cause more injury. Only a veterinarian should manipulate the knee and the patella.

If your dog has a Grade 3 or 4 patellar luxation and a vet pops the patella into place, it will quickly pop out again. These cases will need surgery to keep the patella in place.

Luxating Patella in Boston Terriers: Complete Guide (Statistics)

How Can You Exercise A Dog With Patella Luxation?

The amount of exercise a dog with patella luxation can do depends on how severe the patella luxation is. I usually do not recommend much exercise restriction for dogs with Grade 1 patella luxation and no symptoms.

Dogs with higher grade luxating patellas that limp all the time or dogs recovering from surgery will need heavy exercise restriction.

For dogs with Grade 2 luxating patellas and intermittent limping, it is best to use common sense. You should be able to walk your dog like normal, but if they start limping or seem uncomfortable, it is probably time to stop exercise. Intense exercise may not be recommended in these cases.

For more specific exercise recommendations, it would be a good idea to speak with your veterinarian as they will give more individualized recommendations for your dog.

Can A Boston Terrier Live With Patella Luxation?

Patella luxation is not a fatal condition, and it will not cause your Boston to die. However, luxating patellas can cause pain so it is best to follow your veterinarian’s treatment recommendations. 

If your veterinarian has recommended surgery, it is because they think that it will help your dog long-term.

How Can You Prevent Patella Luxation In Dogs?

Unfortunately, there is no way to prevent hereditary patella luxation in dogs. The best way to reduce patellar luxation incidence is not to breed dogs who have been diagnosed with luxating patellas.

As we know, this condition is likely genetic. It is best not to breed dogs who have luxating patellas. Stopping the hereditary passing of luxating patella may decrease the overall incidences in dogs.

Also, because a few cases of luxating patellas are caused by trauma, always keep your dog on a leash when walking them outside to reduce the risk of traumatic injury. 

Luxating Patella in Boston Terriers: Complete Guide (Statistics)

Does Patellar Luxation Cause Any Long-Term Issues For Dogs?

Patellar luxation can predispose your dog to develop other orthopedic conditions such as a torn ACL or canine arthritis. 

Torn ACL

One of the most common conditions that occur in dogs with luxating patellas is torn ACL ligaments. 

The cranial cruciate ligament, also known as the ACL, works to stabilize the knee. If this ligament ruptures, the knee becomes very unstable. This condition is very painful and often requires surgical repair.

Note: The cranial cruciate ligament is one of the most important stabilizers inside the canine knee (stifle) joint, the middle joint in the back leg. In humans, the CrCL is called the anterior cruciate ligament (ACL) (source).


Canine degenerative joint disease, also known as dog arthritis, can develop in dogs with patellar luxation. With patella luxation, there can be an uneven strain on the joints. This leads to inflammation with the joints, particularly the knee joint.

Arthritis can be reduced with prompt surgery after diagnosis. Early surgery can slow down the progression of arthritis in the affected knee.

If Someone Thinks Their Boston Terrier Has Patella Luxation, What Should They Do?

If you suspect that your Boston has a luxating patella, the first step is to speak with your veterinarian. Limping in dogs can be caused by a variety of issues, and only your veterinarian will be able to accurately diagnose a luxating patella.

Your veterinarian can quickly diagnose a luxating patella just by feeling the knee, so if your pup has been limping lately, I recommend consulting your veterinarian.

Want to speak with a veterinarian right now? Visit the Boston Terrier Society page Speak With A Vet Now for options.

Luxating Patella in Boston Terriers: Complete Guide (Statistics)

A Few Final Thoughts

Boston Terriers may be at a higher risk for patellar luxation than other dog breeds, and it is estimated that around 5 percent of Boston Terriers have luxating patellas.

The most common symptoms of luxating patella include limping in one or both back legs or skipping when running or walking.

For Grade 1 luxating patellas, surgery is not recommended as these kneecaps only pop out when manipulated (speak with your vet). For Grades 2, 3, and 4, surgery may be recommended depending on the severity of your dog’s symptoms.

If your Boston has been limping or skipping, be sure to consult with your vet and inquire about patellar luxation.


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Addie Reinhard, DVM

Addie Reinhard, DVM- Dr. Addie Reinhard is an experienced small animal veterinarian. She is a Boston Terrier lover and always enjoys caring for her Boston patients at the veterinary clinic. She is passionate about providing helpful educational resources to pet parents regarding animal diseases and preventative care. She lives in Lexington, KY with her husband, greyhound, and four cats.

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