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Patellar Dislocation in Dog: Symptoms and Treatment of Disease

Dislocation of the dog's kneecap

Patellar dislocation is a commonly recognized orthopedic problem in dogs.

Every now and then we hear information in the mass media about injuries and injuries of our favorite athletes, famous footballers, tennis players, not to mention people who practice more contact fields and involve a higher risk.

These athletes, as a result of bone fractures, damage to the ligaments in the knee, must stop occurring in their field for a while, often undergo surgery and then undergo rehabilitation, sometimes lasting many months, in order to return to sport and be able to take the first places again.

During treatment, of course, they are excluded from participation in matches or competitions, and we lose sight of them for a moment and we cannot be passionate about the course of rivalry and competitions.

Practicing high-performance, contact sport, fighting with another player is inherently associated with the possibility of injury and each player is aware of such a risk.

And what about our pupils, dogs of various breeds and colors?

After all, they, in most cases, "do not play" spectacular, highly traumatic sports, thus not exposing themselves to the possibility of a serious injury.

Do not therefore suffer from orthopedic problems?

Or maybe some of their diseases have a different background and are not always associated with heavy use of the locomotor system?

Of course, there are many more questions, such as whether all dogs suffer from certain orthopedic diseases evenly and maybe it depends on their lifestyle, condition, body weight?

In the article I will try to dispel some of these doubts in the most accessible way possible, answer some of the questions posed, bringing the reader closer to the problem often, if not common, in dogs, mainly small breeds, such as dislocation of the kneecap.

  • What is the kneecap and how the knee joint works?
  • What is a kneecap dislocation in a dog?
  • What breeds get kneecap dislocation?
  • Why is the kneecap dislocated?
  • Habitual congenital dislocation of the kneecap and breeding of purebred dogs
  • Patellar dislocation degrees
  • Patellar dislocation symptoms in dog
  • Diagnosing
  • Patellar dislocation in dog treatment
    • Dislocation of the kneecap in a dog: surgery
  • Prognosis

What is the kneecap and how the knee joint works?

Kneecap (pour. patella) is a small flat ankle that builds, together with the femur and tibia, the knee joint (the fibula connects to the joint to a very limited extent).

It is located in front of the knee and together with the femur, building the patellofemoral joint in an extremely important way, affecting the smooth functioning of the knee.

It performs a protective function of the knee joint by performing a work similar to shock absorber in mechanical devices, and being a support point for the levers of the quadriceps muscle of the thigh, it facilitates the extension of the knee.

The knee joint, being one of the main joints in the pelvic limb of the dog, performs straightening and bending movements while moving, during which the patella moves in a straight line up and down using the trough created by the femoral block.

The knee joint (lat. articulatio genus) functions as a hinge joint allowing you to perform, as already mentioned, the essential flexion and extension movements.

In dogs, as well as in humans, the knee joint is one of the most stressed joints in the body, hence it must be additionally strengthened with other structures included in its composition.

Therefore, the stabilization and efficient operation of the pond are favorable external ligaments (articular and collateral capsule) and internal in the form of cruciate ligaments (m. in. anterior and posterior), and a better fit of the articular surfaces is guaranteed by two meniscus.

To sum up, the dog's knee joint does not differ much from the human knee joint and is one of the most complex joints in the body subjected to extraordinary strain and therefore deserves "special treatment and protection ".

What is a kneecap dislocation in a dog?

The simplest term to describe the essence of the disease is displacement of the patella to the medial or lateral side beyond the edge of the femoral block.

As a rule, the kneecap is in its physiological position when the animal is moving slowly or lying down.

During the dynamic flexion of the limb and the knee joint, with certain abnormalities in the joint, while performing fast movement, standing up, running, it may fall out and dislocate, causing orthopedic problems.

Patellar dislocation is a fairly common disease and if we were to attempt some generalization, it would dogs of small breeds.

In the case of dislocation, we are dealing with a disturbance in the alignment of the most important elements of the knee joint in a straight line, that is:

  • quadriceps muscle,
  • kneecaps together with the straight ligament,
  • femoral block.

It is obvious that such displacement affects the quality of work of the knee joint and is one of the most common pathologies in this area and, of course, clinical symptoms.

Patellar dislocation can be single-joint or bilateral.

It can also be genetically determined and be congenital, and then we are talking about a habitual dislocation of the kneecap or result from a past injury and be acquired in nature.

Due to the side in which the kneecap is displaced, we deal with a dislocation in the medial direction (approx 80- 90% cases mainly in small breed dogs) or side (up to twenty% cases in large and giant breeds).

It is also worth noting that in approx twenty% cases, the problem of dislocation of the patella occurs in both knees.

On the other hand, dislocation due to a mechanical injury caused by an accident is relatively rare.

There may also be a dislocation of the patella accompanying damage to the anterior cruciate ligament, one of the important structures stabilizing the joint.

What breeds get kneecap dislocation?

Dislocation of the patella predisposed breed

Patellar dislocation is much more common in patients dogs than cats and in females than in males.

The disease mainly affects the representatives of small and miniature breeds, i.e. typical companion animals or the so-called. "Sandwich makers ", the leading among which are:

  • Yorkshire terrier,
  • poodle,
  • chihuahua,
  • papillon,
  • Pekingese,
  • miniature pinscher,
  • dachshund,
  • boston terrier,
  • chow-chow,
  • beagle dogs.

This is where it occurs habitual dislocation, congenital genetically determined, which we most often encounter in clinical practice.

In larger breeds, where there is a lateral dislocation, the problem also makes itself felt.

So let's not be surprised when we hear such a diagnosis in:

  • boxer,
  • Great Dane,
  • labrador,
  • golden retriever,
  • rottweiler.

Why is the kneecap dislocated?

The causes of the genetic background predisposing to the disease have not been thoroughly understood and identified so far.

The culprits are believed to be in a greater number of undefined genes with the participation of environmental factors.

Patellar dislocation is manifested in animals in young age and is not directly related to the trauma, which makes it possible to suspect a congenital background.

Although we cannot observe it immediately after the puppy is born, there are already some anomalies in the structure of the pond, which will predispose to patellar dislocation.

When the puppy starts an independent, active life, at an age 2-6 months as a rule, dislocation occurs.

Simply put, it can be said that dislocation of the patella occurs when individual elements of the knee joint are not arranged in a straight line, which results in a non-physiological curvature of the growing limb.

Therefore, we include all predisposing factors knee joint pathologies headed by:

  • underdevelopment of the medial crest of the femoral block,
  • abnormal position of the tibial tuberosity,
  • shallowness of the femoral block,
  • disturbance of the shape and size of the kneecap,
  • generalized joint laxity,
  • pathology of the quadriceps muscle of the thigh,
  • abnormal rotation of the tibia,
  • any postural defects (valgus or varus of the femur).

Any previous injuries associated with damage or rupture of the ligaments stabilizing the knee joint (cruciate ligaments) predispose to dislocation of the patella.

The age of the onset of the disease is also important, and so:

  • dislocations on the side medial mainly found in puppies 4-6 months small breeds and miniature,
  • dislocations on the side side at small breeds at the age of 5-8 years and young 5-6 month old puppies of large breeds and huge.

So we can clearly see how many factors can affect the occurrence of the disease and how many are still not fully characterized and unknown.

Habitual congenital kneecap dislocation and breeding of purebred dogs

Since we suspect that the above problem may have an innate, genetic background, it is worth considering what we can do to eliminate at least some of the potential factors causing it and thus reduce the incidence of the disease.

Although the mechanism of inheritance has not yet been known, as well as the genes responsible for the occurrence of pathology, it seems advisable to eliminate from breeding those parents with habitual dislocation of the patella.

Responsible breeders, knowing about the problem of their best parents, will not breed them.

The future owners of the dog must also remember that even the mating of parents free from this pathology, which was confirmed by radiological diagnostics of the joints, does not guarantee obtaining offspring without the habitual dislocation of the patella.

However, such an action is medically justified because it significantly reduces the risk of disease.

Patellar dislocation degrees

Patellar dislocation can be of various severity and manifest with symptoms of a different intensity, hence several degrees of this disease have been distinguished, which takes into account the Singelton classification.

The normal knee joint is characterized by the patella in the femoral block, it is normal on an X-ray and shows no pathology during its work, i.e. movement.

  1. The first stage (almost normal knee joint, no movement disorders) is described as the kneecap placed in the femoral block, although it is possible to dislocate the kneecap with a small amount of force when the joint is straightened. When we stop using force or during the flexion phase, the kneecap returns to its correct position and lameness occurs occasionally.
  2. In the second stage (loose position of the kneecap, dislocation during flexion), the patella slips off the pulley more easily than in the first stage, especially in flexion and twisting of the joint. This process is accompanied by variable lameness and, over time, damage to the articular cartilage.
  3. The next stage (significant displacement of the patella) is accompanied by the permanently displaced patella and twisting of the tibia. The animal lifts the limb while it moves. During knee flexion and extension, abduction and adduction of the ankle joint are observed.
  4. And finally, the most advanced degree of patellar dislocation (stage four - patellar dislocation requiring surgical intervention), characterized by the most severe changes and symptoms. The kneecap is permanently dislocated and the limb is sometimes completely unburdened or both knee joints contract when the process is bilateral.

All these degrees can be accurately confirmed by exercising radiological examination the affected limb or limbs.

Patellar dislocation symptoms in dog

Patellar dislocation symptoms: soreness and reluctance to move

The symptoms that we can notice are not uniform and depend on many factors, the most important of which are:

  • degree of dislocation,
  • the direction of movement of the kneecap,
  • age of the dog,
  • degree of activity,
  • the body weight of the animal.

The frequency of dislocations is also important: whether several times a year or even several times a day.

Symptoms do not always have to be evident, which definitely makes it difficult to make an accurate diagnosis and start proper treatment.

Well-muscled, non-overweight dogs with a milder form of dislocation may only show abnormal body posture and gait without obvious signs of disease.

Sometimes we may be disturbed by "other than usual " raising the pelvic limb, temporarily holding it in a bent position and lowering it.

Typical lameness with manifestation of discomfort during movement may occur rarely and usually disappears when the kneecap snaps into its physiological position.

Very often the disease begins with a sudden but short-term lameness that occurs while the dog is moving or playing, which, often underestimated, usually disappears.

So we can see how difficult it is sometimes for the owner to come to the clinic when his dog shows such nonspecific and transient symptoms.

In more advanced forms, lameness lasts longer and is accompanied by other symptoms of an inflammatory reaction, such as:

  • soreness,
  • elevated temperature of this area,
  • tissue swelling, which is a consequence of the ongoing degeneration process in the knee joint.

In even more advanced stages of the disease, we will observe:

  • limb stiffness,
  • variable gait,
  • reluctance to move,
  • valgus or varus limbs,
  • problems with overcoming obstacles, climbing stairs or jumping.

In the video below you can see what a patella dislocation looks like in a chihuahua (grade 2)

Chihuahua mit Patellaluxation Grad 2
Watch this video on YouTube


As I mentioned, disease symptoms do not always have to be evident, strongly marked and therefore may be overlooked, hence the importance of early diagnosis and treatment in any disease.

The diagnosis of patellar dislocation should be a multi-stage process.

As in any other case, it comes first medical interview, from which we can obtain very valuable information about the dog itself, its way of moving or the circumstances of the problem.

Then we move on to clinical trial the dog focused on the assessment of posture and behavior during movement and rest, supplemented by palpation of the pelvic limbs and assessment of the pelvis.

Examination by palpation of the knee joint allows you to assess the scope of the joint's work, its outline, the position of the patella in relation to the femoral block, or its possible lateral or medial displacement.

Only then we sedate the dog pharmacologically and perform it imaging tests confirming or excluding our suspicions. All radiological techniques with X-ray image of the knee joint at the forefront.

Sample X-ray showing dislocation of the patella (on the left side before reduction, on the right side)

Patellar dislocation x-ray | source: wikipedia

Newer diagnostic techniques in the form of computed tomography if magnetic resonance imaging.

All of them are designed to determine the possible displacement of the kneecap in relation to the femoral block.

Of course, sometimes taking an X-ray, especially in very young animals, may not give grounds for a reliable diagnosis, which results from the difficulties in interpreting the radiographs.

Radiological examination will also help detect other skeletal disorders, which is extremely important from the point of view of differential diagnosis.

Detailed methods of presenting changes in this case certainly remain computed tomography if magnetic resonance imaging but the availability and cost of testing are often beyond the reach of many pet keepers.

An example of an MRI showing a dislocation of the patella

Dislocation of the patella - MRI | source: wikipedia

Congenital patellar dislocation may not cause pain reactions and may be diagnosed during a visit to a clinic with another problem or during ordinary prophylaxis, vaccinations.

In the differential diagnosis, we must take into account:

  • any arthritis,
  • fractures,
  • neurological diseases,
  • juvenile osteitis,
  • necrosis of the femoral head,
  • joint dysplasia.

Remember that an accurate diagnosis, preferably in the puppy period, creates the greatest therapeutic possibilities.

Patellar dislocation in dog treatment

So far, no uniform treatment regimen depending on the severity of disease symptoms has been developed.

If our dog, despite a dislocation of the patella, does not show clinical symptoms and dislocations occur sporadically (eg. 1st degree dislocation), we can first attempt to o pharmacological treatment.

Conservative therapy will focus on combating disease symptoms associated with inflammation and pain in the joint.

So we can use drugs from the group, preferably short-term non-steroidal anti-inflammatory drugs, steroid drugs if opioids.

As a supportive treatment, it can be extremely helpful physical therapy, if rehabilitation in water.

Laser therapy we can use it to eliminate the inflammatory joint affecting the tissues that build the joint and thus counteract the degenerative process.

All these measures should relieve pain and create better conditions for a speedy recovery.

Dislocation of the kneecap in a dog: surgery

Dislocation of the patella - magnetic resonance imaging

However, the main therapeutic steps in the event of a patellar dislocation remain operational methods.

The indications for surgery include puppies with 3rd and 4th degree dislocation.

Early treatment (3 - 4 months of age) by eliminating disease symptoms, it prevents muscle contractures as well as changes in soft tissues.

Dogs of heavier breeds with greater body weight, operated on early, will not be exposed to degenerative processes of cartilage or a block of the femur.

Operational management is generally based on plastics of soft and bone tissues.

In mild cases (first degree patellar dislocation), we can settle only with soft tissue plastic surgery, in other cases we use a combination of both methods.

Surgical techniques are based on:

  • plastics of the cord,
  • plastics of the wide fascia,
  • patellar dosing seam,
  • excision of a fragment of the joint capsule and wrinkling of the joint capsule,
  • "Releasing " the quadriceps.

Bone plastic surgery techniques eliminate kneecap dislocation by eliminating bone abnormalities.

They consist of:

  • deepening of the femoral block,
  • prosthetic block,
  • removal of the kneecap,
  • displacement of the tibial tuberosity.
The management after surgery requires restriction of the animal's movement for a period of time 4-6 weeks.

Sometimes a dressing is placed for a few days after surgery in order to limit the animal's mobility.

In the case of extremely active individuals, the only solution may be cage, in which the patient will spend the recovery time.

Rehabilitation after surgery

After the surgery, we use traditional covers antibiotics and analgesic treatment.

In the case of muscle atrophy and limb failure, it is worth considering the animal's rehabilitation.

As with any surgical procedure, all techniques are associated with the possible complications which should be carefully remembered.

Failures in the form of re-dislocation of the patella may affect up to half of the operated animals.

It is comforting that the resulting dislocation usually does not give clinical symptoms and is much less severe than before the surgery.

Complications may result from the excessive mobility of the patient, especially when the pain begins to subside.

Sometimes there are mechanical damage to the surgical wound, periodic lameness or infections.


The prognosis for first, second and third degree dislocations is very good, with full recovery.

In older animals (over 6 months) with grade IV patellar dislocation, we must take into account a cautious prognosis.


Is it possible to prevent dislocations of the kneecap?

In the case of dislocation of the patella in dogs, we can clearly see that not all orthopedic problems must be related to mechanical trauma.

A sudden onset of lameness, especially in a young, growing puppy, even transient over time, should in any case be an indication for a medical consultation.

Do not be afraid to ridicule or define us as "hypersensitive people" about their pets, the more that taking possible treatment early results in very good prognosis.

Patellar dislocation is quite common in the dog population and cannot be marginalized or overlooked.

It is better to always do "a little too much than too little " and then not regret it, and it is best to enjoy the best health throughout your life, which I wish to all readers and your pupils.

You have questions about a kneecap dislocation in a dog? Or maybe your pet is struggling with this condition? Publish them now under the article, I will answer as soon as possible.

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