Patellar luxation in dogs occurs when the kneecap slips out of the groove where it normally sits in the knee joint. It is also called a luxating patella or dislocating kneecap. Affected dogs may suddenly skip a few steps, hold up a back leg or develop persistent lameness. Some experience very little discomfort, while others develop pain, joint damage and reduced mobility.

If you have noticed your dog occasionally hopping on three legs before walking normally again, patellar luxation is one possible explanation. The condition is particularly common in small breeds, although dogs of any size can be affected.

This guide explains the symptoms, causes, inherited risks, four grades of patellar luxation, treatment options and long-term outlook.

What Is Patellar Luxation in Dogs?

The patella is the kneecap, a small bone located within the tendon of the large muscles at the front of the thigh.

In a healthy knee, the kneecap moves smoothly within a groove at the lower end of the thigh bone, called the femur. This arrangement helps the leg bend and straighten efficiently.

Patellar luxation develops when the kneecap moves outside this groove. The displacement may be temporary or permanent, depending on the severity.

What Is the Difference Between Medial and Lateral Patellar Luxation?

Medial patellar luxation occurs when the kneecap moves towards the inside of the leg. This is the most common form, particularly in small dogs.

Lateral patellar luxation occurs when the kneecap moves towards the outside of the leg. It is less common overall but is seen in some larger breeds.

The condition can affect one knee or both knees.

What Are the Symptoms of Patellar Luxation in Dogs?

The most recognisable symptom is a skipping gait, where a dog suddenly lifts a back leg for several steps before using it normally again.

This often happens when the kneecap slips out of position and then returns to its normal groove.

Early Signs of a Luxating Patella

Look for the following changes:

• Occasionally lifting one back leg while walking or running.
• Skipping or hopping for several steps.
• Suddenly stretching or kicking a hind leg backwards.
• Intermittent limping that disappears quickly.
• Reluctance to jump onto furniture or climb stairs.
• Stiffness after exercise or resting.
• Reduced enthusiasm for longer walks.

Some dogs with mild patellar luxation show no obvious symptoms. The condition may only be discovered during a routine veterinary examination.

What Does Severe Patellar Luxation Look Like?

More advanced cases may cause persistent lameness, an abnormal walking posture, muscle loss and difficulty straightening the affected leg.

Dogs with severe developmental abnormalities may appear bow-legged or walk with their knees permanently bent.

Sudden severe lameness can also indicate a cruciate ligament injury, fracture or another painful condition. Do not assume that every limp is caused by a luxating patella.

Our guide to why dogs limp while acting normally

What Causes Patellar Luxation in Dogs?

Most cases develop because the bones, muscles and tendons surrounding the knee do not align normally as the dog grows.

Developmental Joint Abnormalities

The groove that normally holds the kneecap may be unusually shallow. The thigh bone or shin bone may also develop with abnormal angles or rotation.

These differences can change the direction in which the muscles pull on the kneecap, allowing it to move outside its normal position.

Patellar luxation is therefore often a problem involving the alignment of the entire hindlimb rather than an isolated defect in the kneecap.

Traumatic Injuries

Less commonly, an injury can damage the tissues stabilising the kneecap and cause it to dislocate.

Traumatic luxation may produce sudden pain and lameness in a dog that previously moved normally.

Does Being Overweight Cause Patellar Luxation?

Excess weight does not usually cause the underlying developmental abnormality, but it increases the mechanical demands placed on an unstable knee.

Maintaining a healthy body condition can reduce unnecessary joint loading and help manage associated discomfort.

Is Patellar Luxation Hereditary in Dogs?

Patellar luxation has a recognised hereditary component, particularly when it develops without an injury.

However, inheritance is complex. Multiple genes and developmental factors may influence the shape and alignment of the hindlimbs.

There is no universal DNA test capable of predicting patellar luxation across all dog breeds.

Dogs with diagnosed developmental patellar luxation should not be used for breeding because they may pass susceptibility to their offspring.

Responsible breeders should follow relevant breed-specific health screening recommendations and consider the joint health of breeding dogs and their relatives.

Which Dog Breeds Are Most Prone to Patellar Luxation?

Patellar luxation is particularly common in toy and small breeds, although larger dogs can also develop the condition.

Chihuahuas

Chihuahuas are among the breeds frequently affected by luxating patellas. Their small size does not prevent knee instability from causing discomfort or long-term joint problems.

Our Chihuahua care guide covers patellar luxation alongside other health considerations for the breed.

Pomeranians, Yorkshire Terriers and Toy Poodles

These breeds have recognised susceptibility to medial patellar luxation, where the kneecap moves towards the inside of the leg.

Owners may first notice a brief skipping movement during play or exercise.

Other Susceptible Breeds

Maltese, Boston Terriers and several other small breeds are also affected.

Larger breeds, including Akitas, Chinese Shar Peis and Great Pyrenees, may develop patellar luxation, sometimes involving more substantial limb deformities.

Breed predisposition increases risk but does not mean that every dog of that breed will develop the condition.

What Are the Four Grades of Patellar Luxation in Dogs?

Vets classify patellar luxation into four grades according to how easily the kneecap moves out of position and whether it can return to its normal groove.

Grade 1 is the mildest form, while grade 4 describes a permanently displaced kneecap that cannot be returned manually.

Grade 1 Patellar Luxation

The kneecap normally stays in place but can be pushed out of the groove during examination. It returns to its normal position when released.

Dogs may show no symptoms or only occasional skipping.

Grade 2 Patellar Luxation

The kneecap can move out of position spontaneously and may remain displaced temporarily. It can usually be returned manually or by extending the leg.

Intermittent skipping and lameness are common.

Grade 3 Patellar Luxation

The kneecap remains displaced most of the time. It can be moved back into position manually but slips out again easily.

Dogs may develop persistent gait abnormalities and visible changes in limb alignment.

Grade 4 Patellar Luxation

The kneecap is permanently displaced and cannot be manually returned to its normal position.

Significant skeletal deformities, abnormal posture and ongoing mobility problems may occur.

Patellar Luxation Grades and Treatment Options

How Do Vets Diagnose Patellar Luxation?

Diagnosis usually begins with an orthopaedic examination.

Your vet will observe your dog walking, assess the affected knee and gently examine how the kneecap moves within its groove.

In many cases, the vet can diagnose and grade patellar luxation by feeling the position and movement of the kneecap.

Are X-rays Necessary?

X-rays may be recommended to assess bone alignment, investigate arthritis or identify other causes of lameness.

Dogs with severe deformities may need advanced imaging, such as CT scanning, before surgery.

Your vet will also assess for other knee problems, particularly cranial cruciate ligament injury, which can occur alongside patellar luxation.

Can Patellar Luxation Be Treated Without Surgery?

Yes. Some dogs with mild patellar luxation can be managed successfully without an operation.

Conservative treatment is generally most suitable for dogs with grade 1 or minimally symptomatic grade 2 disease.

Weight Management

Maintaining a lean body condition reduces unnecessary loading on the knee and helps support comfortable movement.

Controlled Exercise and Physiotherapy

Appropriate walking and rehabilitation exercises can help maintain muscle strength around the knee.

Activities should be tailored to the individual dog. Repeated jumping, sudden turns and intense exercise may aggravate symptoms.

Pain Management

Your vet may prescribe suitable pain relief when inflammation or discomfort is present.

Non-surgical treatment can improve comfort and function, but it does not correct the underlying bone alignment or permanently reposition an unstable kneecap.

The PDSA explains why mild cases may be managed conservatively while more symptomatic cases often benefit from surgery.

When Does a Dog Need Surgery for Patellar Luxation?

Surgery is commonly considered when patellar luxation causes repeated pain, frequent lameness, worsening mobility or significant limb deformity.

Many grade 3 and grade 4 cases require surgical assessment, although treatment decisions must consider the dog's age, general health and individual circumstances.

What Happens During Patellar Luxation Surgery?

The aim is to restore normal kneecap tracking and improve knee stability.

Depending on the abnormalities present, the surgeon may deepen the groove in the thigh bone, reposition the attachment of the kneecap tendon or adjust the surrounding soft tissues.

More severe cases may require correction of abnormal bone alignment.

Several techniques are often combined during the same operation.

Is Patellar Luxation Surgery Successful?

Many dogs experience substantial improvements in mobility and comfort following surgery.

The ACVS reports that more than 90 per cent of owners are satisfied with their dog's progress after surgical treatment.

However, complications can occur, including infection, implant problems, persistent lameness or recurrence of instability.

The outlook may be more complicated in dogs with severe skeletal deformities or additional joint disease.

How Long Does Recovery Take After Patellar Luxation Surgery?

Recovery usually involves several weeks of carefully restricted activity followed by gradual rehabilitation.

Your dog may need lead-only toilet breaks, a confined resting area and medication for pain control.

Running, jumping and unrestricted play are generally avoided during early healing.

Depending on the procedure, rehabilitation and return to fuller activity may take approximately eight to twelve weeks or longer.

Your surgeon will provide a specific recovery plan, which may include follow-up X-rays and physiotherapy.

Following these instructions is important because excessive activity can interfere with healing.

Can Patellar Luxation Cause Arthritis in Dogs?

Yes. Repeated displacement of the kneecap can damage joint cartilage and contribute to osteoarthritis.

Dogs with persistent instability may develop chronic inflammation, stiffness and reduced mobility as they age.

Patellar luxation is also associated with an increased risk of cranial cruciate ligament problems in some dogs.

Early management may help reduce discomfort and improve joint function, although surgery cannot guarantee that arthritis will never develop.

For more information about cartilage, ligaments and joint health, read our guide to how dog joints work.

How Can You Help a Dog With a Luxating Patella at Home?

Simple adjustments can make daily activities more comfortable for dogs with knee instability.

Consider the following:

• Maintain a healthy body weight.
• Provide regular, controlled exercise appropriate to your dog's condition.
• Use non-slip rugs on smooth floors.
• Limit repeated jumping onto furniture.
• Consider ramps where appropriate.
• Keep nails trimmed to improve grip.
• Monitor changes in walking, stiffness and willingness to exercise.

Joint supplements may provide nutritional support, but they cannot correct a displaced kneecap or replace surgery when structural correction is needed.

If your dog suddenly becomes unable to bear weight, develops significant swelling or appears very painful, arrange prompt veterinary assessment.

Frequently Asked Questions About Patellar Luxation in Dogs

Can a Luxating Patella Fix Itself?

A kneecap may return to its normal position spontaneously, particularly in mild cases. However, this does not mean the underlying anatomical problem has resolved.

Is Patellar Luxation Painful for Dogs?

Some dogs with mild luxation show little discomfort. Others experience intermittent or persistent pain, particularly when instability causes inflammation or arthritis.

Can a Dog Live Normally With Patellar Luxation?

Yes. Many dogs with mild disease enjoy normal activities with appropriate monitoring. Dogs with more severe disease may need surgery or long-term management.

Should You Walk a Dog With a Luxating Patella?

Controlled walking is often beneficial, but exercise should reflect the dog's symptoms and veterinary recommendations. Avoid activities that repeatedly trigger pain or lameness.

Can Grade 2 Patellar Luxation Get Worse?

Yes. Some grade 2 cases remain relatively stable, while others become more symptomatic or progress over time. Regular veterinary reviews help identify changes.

Does Patellar Luxation Shorten a Dog's Life?

The condition does not usually shorten life expectancy directly. However, severe untreated pain and mobility problems can significantly affect quality of life.

Can Patellar Luxation Affect Both Back Legs?

Yes. Both knees may be affected, even if symptoms are more noticeable in one leg.

Final Thoughts

Patellar luxation in dogs ranges from a mild, occasional skipping gait to a serious joint condition requiring surgery.

Recognising symptoms early, maintaining a healthy weight and seeking veterinary assessment can help protect long-term mobility.

If your dog repeatedly lifts a back leg, limps or struggles to move comfortably, arrange a veterinary examination. Our guide to common medical conditions in dogs and their warning signs

This article provides general educational information and does not replace individual veterinary diagnosis, treatment or emergency care.