Patellar Luxation: Understanding this problem, Causes, Solutions

Patellar Luxation:  What You Should Know About that Trick Knee

by Janice Jones     |Last Updated 05-24-2023

Patellarluxation, luxating patella, dislocated kneecap, trick knee, and floating kneecaps are terms that refer to a condition where the kneecap can move in and out ofposition. 

Patellar luxation occurs mostly in toy and small breeds of dogs weighing22 pounds or less, but can occur in dogs of all sizes. 

In the majority of cases, luxation is a congenital conditionand shows up as soon as puppies begin to walk. In other dogs, it may appear some time later.

It is most likely inherited though the exact mode of transmission is notknown.

Breeds Affected with Patellar Luxation

Most breedsthat are affected are tiny, small or medium sized dogs.  According to the Orthopedic Foundations ofAmerica, the breed most acutely affected is the Pomeranian with a whopping 37.2 percent affected followed by theYorkshire Terrier at a rate of 24.4 percent affected.

Patellar Luxation is very common in Yorkshire Terriers

Other small breed dogs that may be affected include:

Tibetan Spaniel

Cocker Spaniel

English Toy Spaniel



Bedlington Terrier

PortuguesePodengo Pequeno


Toy Fox Terrier


Shiba Inu

Less common, but still an issue, patellar luxation is diagnosed in thesesmall breed dogs:

French Bulldogs


Lhasa Apso

Norwich Terrier


Norfolk Terrier

Tibetan Terrier

American Hairless

Cairn Terrier

Coton de Tulear

Brussels Griffon

Biewer Terrier


Bichon Frise


Rat Terrier

Shetland Sheepdog


Silky Terrier


West Highland White Terrier


Chinese Crested





A little dogcould be having fun running around and playing. Suddenly he stops and holds up his leg as if he can no longer walk. 

The next instance, his leg is back to the ground,and he’s back to running and playing. There is usually pain associated with the knee popping out and then againwhen it pops back in.  In young dogs, it’s hard to notice this pain because it isfleeting.

You mightjust see ashort limp, even a skip as the dog runs or trots, or a sudden loss ofsupport.  Some dogs sit oddly where theirknee is placed outward rather than tucked in. Any of these symptoms will be intermittent with the dog returning tonormal within a very short period of time.

Over time,the knee cartilage wears thin because ofthe frequent movement in and out of the grove. At this point, there will be a bone to bone contact,and this is when the dog begins to feel severe pain.

Some dogsmay rupture their cranial cruciate ligament. Dogs Naturally Magazine reportsthat at least 15% to 20% of dogs with patellar luxation will at some pointsuffer from a cruciate ligament rupture. 

Levels of Severity

Veterinariansgrade the degree of severity by assigningit to one of four levels:

Grade1:  The Kneecap pops out and then popsright back in.  (The veterinarian canmanually do this manipulating during a routine office visit) Oftennewborn puppies will show signs of abnormal hind leg carriage as early as whenthey start walking. 

Grade2:  The kneecap pops out but doesn’t popback spontaneously and may need help to manually manipulate it back into place.

Grade3: The kneecap rests outside the grove most of the time, but it can be manually setback where it will only stay for a small time period.

Grade4:  The kneecap remains outside the groveand won’t stay in place even whenmanually put back in place. Often newborn puppies who eventually getdiagnosed with Grade 3 or 4 will show signs of abnormal hind leg carriage asearly as when they start walking. 


Veterinarianswill likely be able to palpate the knee joint and manually manipulate it in andout of place. 

Sometimes sedation isnecessary to do this.  X-rays or a CATscan will be helpful and likely ordered if surgery is to occur.

They are also done to rule out or identify other orthopedic problems that may also be affecting the dog.

Treatment Options

Surgery would be the lasttreatment of choice, especially if thedog diagnosed with a grade 3 or 4 luxated patella.  

During surgery, the veterinarian will carveout a deeper groove at the end of the femur so that the kneecap can remain inplace.  If there is a ruptured ligament,it can be repaired at the same time. 

But beforesurgery is scheduled there are other things that you can do to improve the dog’soverall quality of life. 

Most dogs witha mild problem will live their entire life without needing surgery.  A few life changes can keep the dog quitecomfortable.

According toDr. Karen Becker, there are several steps that you can do.  She recommends that dogs with this problemmaintain a healthy body weight.  Lessstress will limit any stress on those joints. 

She also suggests that the dog should keep moving, which is in directcontrast to older thinking that recommended dogs remain as still as possible.

Lastly, she encourages you to provide an oral joint supplement such as chondroitin/glucosamine.  

Dr. JulieMayer, a holistic vet, and owner ofIntegrative Pet Care and operator of Therapistin Chicago, recommends certain exercisesthat can help with the condition.    

Amongthe treatments that she encourages includes swimming and underwater treadmills,going up and down carpeted steps several times a day and leg weights. 

Painrelievers and anti-inflammatory drugs may also be prescribed and may make thedog more comfortable.

Changing thediet or adding additional nutrients can also be effective.  The goal of supplements is to control inflammationand inflammation and prevent osteoarthritis. 

At the same time, the diet should supply antioxidants, provide buildingblocks for the synthesis of collagen and promote healthy connective tissue. 


Since thisis an inherited condition, dogs that areaffected should not be bred.

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