Patellar Luxation in Dogs: Symptoms, Diagnosis & Treatment

Patellar luxation is a common orthopedic condition in dogs in which the kneecap (patella) slides out of the groove at the front of the knee joint where it normally sits. It is one of the most frequently diagnosed hindlimb abnormalities in dogs, affecting an estimated 7% of puppies and occurring in dogs of all sizes and breeds. Left untreated, patellar luxation can lead to progressive cartilage damage, chronic pain, and debilitating arthritis.

> Disclaimer: This article is for informational purposes only and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a licensed veterinarian for any concerns about your dog's health.

What Is Patellar Luxation?

The patella is a small, oval-shaped bone embedded in the tendon of the quadriceps muscle group. It glides within a groove called the trochlear groove on the front surface of the femur (thighbone) every time your dog bends or extends the knee. In a dog with patellar luxation, the patella dislocates—or "luxates"—to one side or the other, moving out of this groove.

Most commonly, the kneecap shifts toward the inside of the leg (medial luxation), which accounts for roughly 80% of cases. Less frequently, the patella shifts to the outside (lateral luxation). In rare cases, a dog can experience luxation in both directions.

When the kneecap is displaced, the knee cannot extend properly, causing the dog to carry the affected leg or skip. In mild cases the patella may pop in and out on its own. In severe cases it remains permanently dislocated, leading to abnormal limb alignment, progressive joint damage, and significant pain.

Veterinarians grade patellar luxation on a scale of I to IV:

• Grade I — The patella can be manually pushed out of position but returns to the groove on its own. The dog rarely shows clinical signs.
• Grade II — The patella luxates spontaneously during movement or with manual pressure and remains displaced until manually repositioned or until the dog extends and rotates the limb. Intermittent lameness is common.
• Grade III — The patella is permanently luxated but can be manually returned to the groove, though it re-luxates immediately. Persistent lameness and abnormal gait are typical.
• Grade IV — The patella is permanently displaced and cannot be manually returned to the groove. The trochlear groove is shallow or absent, and significant skeletal deformities may be present. Severe lameness and inability to fully extend the knee are seen.

Symptoms of Patellar Luxation in Dogs

Symptoms vary widely depending on the grade and whether one or both knees are affected.

Early Signs

• Intermittent skipping or "bunny hopping" — Your dog may suddenly lift one hind leg for a few strides, then resume walking normally. This is the hallmark early sign.
• Momentary leg extension — You may notice your dog pausing mid-stride, kicking the leg out behind them to pop the kneecap back into place.
• Reluctance to jump — Dogs may hesitate before jumping onto furniture, into the car, or up stairs.
• Occasional stiffness after rest — Mild stiffness when rising from a nap that resolves within minutes.
• Subtle gait asymmetry — A slightly bowlegged or knock-kneed stance that is easy to overlook.

Progressive Symptoms

• Increased frequency and duration of lameness — Episodes occur more often and last longer.
• Persistent abnormal gait — A crouched, bowlegged posture with the knees rotated inward (for medial luxation) or outward (for lateral luxation).
• Muscle atrophy — Visible loss of muscle mass in the affected limb due to decreased use.
• Audible clicking or popping — A click heard or felt when the patella shifts in or out of the groove.
• Pain on palpation — The dog may flinch, yelp, or pull away when the knee is touched or manipulated.
• Reduced activity level — Decreased interest in walks, play, or exercise.
• Difficulty sitting or rising — Struggle to transition between positions, or sitting with the affected leg splayed to the side ("lazy sit").

Emergency Signs

Seek immediate veterinary care if you observe:

• Sudden, complete inability to bear weight on a hind leg — This may indicate a concurrent cruciate ligament tear, which occurs in 15–20% of dogs with patellar luxation.
• Severe swelling or deformity of the knee — Could signal fracture, ligament rupture, or joint infection.
• Acute onset of pain — Persistent crying, whimpering, or aggression when touched near the knee.
• Both hind legs affected simultaneously with collapse — This can mimic neurological emergencies and warrants urgent assessment.

What Causes Patellar Luxation in Dogs?

Genetic and Congenital Factors

The vast majority of patellar luxation cases are congenital or developmental, meaning the dog is born with structural abnormalities that predispose the kneecap to displacement. These include:

• A shallow or absent trochlear groove
• Misalignment of the quadriceps muscle group
• Rotational deformities of the tibia (shinbone) or femur
• Abnormal hip joint conformation

Traumatic Causes

A smaller percentage of cases result from direct trauma to the knee, such as being hit by a car, a hard fall, or a collision during vigorous play. Traumatic luxation can occur in any breed and is more commonly lateral.

Contributing Risk Factors

• Obesity — Excess body weight increases mechanical stress on the knee joint and accelerates cartilage deterioration.
• Rapid growth — Puppies that grow too quickly, especially on calorie-dense diets, may develop skeletal misalignment.
• Lack of muscle conditioning — Weak quadriceps muscles offer less support to keep the patella tracked properly.
• Age — While signs typically appear by 4–6 months of age in congenital cases, clinical symptoms may not become apparent until middle age, when cumulative joint wear causes pain.

Breeds Most at Risk

Patellar luxation can occur in any dog, but certain breeds carry significantly higher risk.

Small and Toy Breeds (Medial Luxation)

Small breeds account for the majority of diagnoses. Predisposed breeds include:

• Yorkshire Terrier
• Pomeranian
• Chihuahua
• Maltese
• Toy and Miniature Poodle
• French Bulldog
• Boston Terrier
• Cavalier King Charles Spaniel
• Papillon
• Bichon Frise
• Jack Russell Terrier
• Shih Tzu

Large and Giant Breeds (Lateral Luxation)

Large breed dogs are more prone to lateral luxation, which tends to be more functionally severe. At-risk breeds include:

• Labrador Retriever
• Golden Retriever
• Great Dane
• Flat-Coated Retriever
• Akita
• Boxer
• Saint Bernard
• Chinese Shar-Pei

How Patellar Luxation Is Diagnosed

Step 1: History and Physical Examination

Your veterinarian will begin with a thorough history—when you first noticed the lameness, how often it occurs, whether it affects one or both legs, and any traumatic events. They will observe your dog's gait while walking and trotting.

Step 2: Orthopedic Examination

The hallmark diagnostic test is a hands-on palpation of the knee. With the dog relaxed (sometimes under mild sedation), the veterinarian will:

1. Feel for the patella's position in the trochlear groove.
2. Attempt to luxate the patella medially and laterally.
3. Assess whether the patella returns to the groove spontaneously.
4. Check for crepitus (grinding sensation), joint effusion (swelling), and pain.
5. Evaluate the cruciate ligaments using the cranial drawer test and tibial compression test.

Step 3: Radiographs (X-rays)

X-rays of the affected knee(s), hip joints, and sometimes the full hindlimb are taken to:

• Confirm the direction and degree of luxation
• Evaluate trochlear groove depth
• Identify concurrent conditions such as hip dysplasia, cruciate disease, or arthritis
• Assess skeletal alignment (femoral and tibial angles)

Step 4: Advanced Imaging (Select Cases)

For surgical planning in Grade III–IV cases or when complex skeletal deformities are suspected, your veterinarian may recommend:

• CT scan — Provides detailed three-dimensional bone assessment and precise measurement of rotational deformities. Cost: $500–$1,500.
• MRI — Evaluates soft tissue structures including ligaments and cartilage in greater detail. Cost: $1,500–$3,000.

Step 5: Blood Work

Pre-surgical blood work (complete blood count, serum chemistry, coagulation panel) is standard to ensure your dog is a safe anesthetic candidate. Cost: $100–$250.

Treatment Options for Patellar Luxation

Treatment depends on the grade, the dog's size, age, pain level, and whether concurrent conditions are present.

Medical Management

Conservative management is typically recommended for Grade I and some Grade II cases where the dog shows minimal clinical signs.

• Weight management — Achieving and maintaining a lean body condition is the single most impactful non-surgical intervention. Even modest weight loss of 6–8% can meaningfully reduce joint stress.
• Non-steroidal anti-inflammatory drugs (NSAIDs) — Medications such as meloxicam or carprofen to control pain and inflammation during flare-ups. Always use veterinary-prescribed NSAIDs; never give human medications.
• Joint supplements — Glucosamine, chondroitin sulfate, and omega-3 fatty acids (EPA/DHA) may support cartilage health, though evidence is variable.
• Activity modification — Avoiding high-impact activities like jumping from heights while maintaining low-impact exercise like controlled leash walks and swimming.
• Physical rehabilitation — Strengthening the quadriceps and surrounding musculature through targeted exercises can improve patellar tracking.

Surgical Options

Surgery is the definitive treatment for patellar luxation and is recommended for Grade II cases with frequent lameness, all Grade III cases, and all Grade IV cases. Several techniques are often used in combination:

• Tibial Tuberosity Transposition (TTT) — The bony attachment point where the patellar tendon inserts on the tibia is cut and repositioned to realign the quadriceps mechanism. This is the most commonly performed procedure.
• Trochleoplasty (Trochlear Groove Deepening) — The trochlear groove is surgically deepened to better contain the patella. Techniques include wedge recession sulcoplasty, block recession trochleoplasty, and trochlear chondroplasty (in young puppies with soft cartilage).
• Lateral Imbrication / Medial Release — The joint capsule on the side the patella luxates toward is released (loosened) and the opposite side is tightened (imbricated) with sutures, pulling the patella back into alignment.
• Corrective Osteotomy — For severe cases with significant femoral or tibial deformity (common in Grade IV), the bone itself may need to be cut and realigned, then stabilized with plates and screws.

Alternative and Supportive Therapies

• Physical rehabilitation / physiotherapy — Post-surgical rehab is critical. Protocols typically include underwater treadmill therapy, therapeutic exercises, range-of-motion work, and cold laser therapy.
• Acupuncture — May provide supplemental pain relief for some dogs.
• Regenerative medicine — Platelet-rich plasma (PRP) injections and stem cell therapy are emerging treatments that may support joint healing, though evidence in veterinary medicine is still evolving.
• Orthotics and knee braces — Custom-fitted stifle braces may provide support for dogs that are not surgical candidates, though they do not correct the underlying anatomical problem.

At-Home Care

• Restrict activity post-surgery — Crate rest or confinement to a small area for 6–8 weeks, with only short, controlled leash walks for bathroom breaks.
• Follow medication protocols — Administer all prescribed pain medications, antibiotics, and anti-inflammatories as directed.
• Monitor the incision — Check daily for redness, swelling, discharge, or opening of the wound. Use an Elizabethan collar to prevent licking.
• Perform prescribed exercises — Gentle range-of-motion exercises and controlled walks as directed by your veterinarian or rehabilitation therapist.
• Provide non-slip flooring — Place rugs or mats on hard floors to prevent slipping during recovery.
• Maintain a healthy weight — Prevent weight gain during the restricted-activity recovery period by adjusting food portions.

Prognosis and Life Expectancy

The prognosis for patellar luxation depends heavily on the grade, timing of treatment, and whether secondary complications have developed.

• Grade I–II (treated conservatively or surgically) — Excellent prognosis. Most dogs live full, active lives with minimal long-term limitations. Surgery, when indicated, has a very high success rate.
• Grade III (treated surgically) — Good to excellent prognosis. Dogs typically regain strong limb function, though mild arthritis may develop over time.
• Grade IV (treated surgically) — Fair to good prognosis. Significant improvement is expected, but some degree of gait abnormality and arthritis is common. Dogs with severe skeletal deformities corrected via osteotomy generally do well but may require longer recovery.

Prevention

While congenital patellar luxation cannot be fully prevented, several strategies can reduce risk and severity:

• Responsible breeding — Dogs diagnosed with patellar luxation should be removed from breeding programs. The Orthopedic Foundation for Animals (OFA) offers patella evaluations for breeding stock, ideally performed at 12 months of age or older.
• Screening puppies — Have your veterinarian check for patellar stability during routine puppy exams, especially in predisposed breeds.
• Maintain a lean body condition — Keeping your dog at an ideal weight throughout life reduces stress on the knee joints.
• Appropriate nutrition during growth — Feed puppies a breed-appropriate diet to support steady, healthy bone development. Avoid overfeeding or excessive calcium supplementation in large breeds.
• Regular, moderate exercise — Build and maintain strong hindlimb muscles through consistent, low-impact activity. Avoid repetitive high-impact activities in at-risk breeds.
• Early veterinary intervention — If your dog begins skipping or showing intermittent lameness, seek evaluation promptly. Early-grade luxation is far simpler and less costly to manage than advanced disease.

Cost of Treatment

Costs vary significantly depending on geographic location, facility type (general practice vs. specialty hospital), severity, and whether one or both knees require treatment.

| Component | Estimated Cost Range | |---|---| | Initial veterinary examination | $50–$150 | | Radiographs (X-rays) | $150–$400 | | Advanced imaging (CT/MRI) | $500–$3,000 | | Pre-surgical blood work | $100–$250 | | Surgery (per knee) | $1,500–$5,000 | | Post-surgical rehabilitation (course) | $500–$2,000 | | Conservative management (annual) | $200–$1,000 | | Ongoing joint supplements (annual) | $200–$600 |

Frequently Asked Questions

Can patellar luxation heal on its own?

No. Patellar luxation is a structural abnormality that does not resolve without intervention. While Grade I cases may never cause clinical problems and can be managed conservatively, the underlying anatomical issue remains. In many dogs, the condition progresses over time, so monitoring by a veterinarian is important even in mild cases.

At what age should my dog have surgery?

Surgery can be performed at any age, but most veterinary surgeons recommend operating once the dog has finished growing—typically around 10–12 months for small breeds and 12–18 months for large breeds. In severe cases (Grade III–IV) with significant pain or skeletal deformity, earlier intervention may be recommended to prevent worsening bone changes.

Is patellar luxation surgery painful?

Dogs experience post-operative discomfort, but modern pain management protocols—including pre-operative nerve blocks, post-operative NSAIDs, and opioid medications—keep dogs comfortable during recovery. Most dogs begin partial weight-bearing within a few days of surgery.

Can my dog still exercise after treatment?

Yes. After full recovery from surgery (typically 8–12 weeks), most dogs return to normal activity levels. Low-impact exercise such as walking and swimming is encouraged. High-impact activities like agility should be discussed with your veterinarian and reintroduced gradually.

My dog was diagnosed with Grade I luxation. Does it need surgery?

In most cases, Grade I luxation does not require surgery. Conservative management—weight control, joint supplements, muscle strengthening, and monitoring—is usually sufficient. However, if the condition progresses to Grade II with frequent lameness, surgical correction should be reconsidered.

Is patellar luxation covered by pet insurance?

Most comprehensive pet insurance policies cover patellar luxation as long as it was not a pre-existing condition at the time the policy was purchased. Some policies impose waiting periods of 6–12 months specifically for orthopedic conditions. Review your policy terms carefully and enroll your pet early, ideally as a puppy.

Can patellar luxation occur in both knees?

Yes. Bilateral patellar luxation (affecting both hindlimbs) is common and is reported in approximately 50% of affected dogs. When both knees require surgery, procedures are typically performed 8–12 weeks apart to allow recovery of one limb before operating on the other.

Should I get a second opinion before surgery?

A second opinion is always reasonable, especially for a surgical procedure. Consider consulting a board-certified veterinary surgeon (Diplomate of the American College of Veterinary Surgeons, or DACVS) for complex or high-grade cases, as they have advanced training and experience in orthopedic procedures.