Luxating Patella in Cavaliers: Understanding Slipping Kneecaps
Luxating patella, commonly known as a "slipping kneecap," is one of the most frequently diagnosed orthopaedic conditions in small dog breeds, including the Cavalier King Charles Spaniel.
While some dogs experience only mild symptoms, others can develop significant pain, lameness, and long-term joint damage if the condition is left untreated. Fortunately, early diagnosis and appropriate management can help many affected dogs maintain a good quality of life.
Understanding what luxating patella is, recognising the early warning signs, and knowing when to seek veterinary advice can make a significant difference to your Cavalier's long-term mobility and comfort.
What Is a Luxating Patella?
The patella, or kneecap, is a small bone that sits within the tendon of the quadriceps muscle at the front of the knee joint.
In a healthy knee, the patella glides smoothly within a groove at the lower end of the femur (thigh bone) as the leg bends and straightens.
A luxating patella occurs when the kneecap slips out of this groove, causing the knee to become unstable.
The kneecap may move:
Towards the inside of the leg (medial luxation)
Towards the outside of the leg (lateral luxation)
In Cavalier King Charles Spaniels and most other toy breeds, medial luxating patella is by far the most common form.
Why Are Cavaliers at Risk?
Luxating patella is particularly common in toy and small breeds because they often have shallower patellar grooves and subtle differences in hind limb alignment.
The condition may be:
Congenital or Developmental: Many dogs are born with anatomical features that predispose them to luxation, although symptoms may not become apparent until later.
Hereditary: Research suggests that luxating patella has a genetic component in many breeds, including Cavaliers. For this reason, responsible breeders often screen breeding dogs for patellar stability.
Traumatic: Luxating patella can also occur following injury or trauma to the knee.
Associated with Ligament Laxity: Young dogs and females during oestrus (season), pregnancy, or shortly after whelping may have increased ligament laxity due to hormonal influences, which can potentially increase the risk of instability in predisposed dogs.
What Happens When the Kneecap Slips?
When the kneecap moves out of its normal groove:
The joint becomes unstable.
Normal movement is disrupted.
Cartilage may become damaged.
Abnormal wear develops.
Arthritis can occur over time.
In some dogs, the kneecap quickly returns to its normal position. In others, it may remain displaced until manually repositioned or surgically corrected.
What Are the Early Signs?
One of the most recognisable signs of luxating patella is a sudden skipping gait.
Owners may notice their Cavalier:
Skipping or Hopping: The dog may briefly carry one hind leg while walking or running before suddenly returning to normal. This behaviour is often intermittent in the early stages.
Occasional Limping: Some dogs develop a mild limp that comes and goes.
Reluctance to Exercise: Affected dogs may become less willing to run, jump, or climb stairs.
Hind Limb Stiffness: Some owners notice stiffness after exercise or rest.
Difficulty Rising: As the condition progresses, dogs may take longer to stand after resting.
Audible Clicking: In some cases, a clicking sound may be heard as the kneecap moves in and out of position.
How Is Luxating Patella Graded?
Veterinarians commonly classify luxating patella using a grading system ranging from Grade I to Grade IV.
Grade I
Kneecap can be manually luxated by the veterinarian.
Returns to normal position immediately.
Minimal clinical signs.
Grade II
Kneecap luxates intermittently.
May remain displaced temporarily.
Intermittent lameness often occurs.
Grade III
Kneecap is luxated most of the time.
Can be manually repositioned but reluxates easily.
More consistent lameness is common.
Grade IV
Kneecap is permanently displaced.
Cannot be manually repositioned.
Significant limb deformity and lameness may occur.
Generally, higher grades are associated with greater clinical impact and a higher likelihood of requiring surgical correction.
How Is Luxating Patella Diagnosed?
Diagnosis is usually straightforward and can often be performed during a routine veterinary examination.
Your veterinarian will:
Observe your dog's gait.
Examine the knee joint.
Assess patellar stability.
Determine the luxation grade.
In some cases, X-rays may be recommended to evaluate:
Joint alignment
Bone structure
Arthritis
Concurrent orthopaedic conditions
What Should You Do If You Suspect Luxating Patella?
If your Cavalier develops:
A skipping gait
Intermittent limping
Difficulty jumping
Hind limb weakness
Signs of discomfort
Arrange a veterinary examination.
Early diagnosis is important because ongoing instability can lead to progressive joint damage and arthritis.
Can Luxating Patella Be Treated Without Surgery?
In some cases, yes.
Dogs with mild luxations and minimal clinical signs may benefit from conservative management.
Weight Management
Maintaining a healthy body weight is one of the most important aspects of treatment.
Excess weight increases stress on the joints and can worsen clinical signs.
Controlled Exercise
Appropriate exercise helps maintain muscle strength, which supports joint stability.
Physiotherapy
Canine physiotherapy may assist by:
Improving muscle strength
Supporting joint function
Enhancing mobility
Reducing discomfort
Rehabilitation Therapy
Hydrotherapy and targeted rehabilitation exercises may also be beneficial for some dogs.
Pain Management
Where arthritis or inflammation is present, veterinarians may prescribe medications to improve comfort and mobility.
When Is Surgery Recommended?
Surgical treatment is generally considered when:
Clinical signs are persistent.
Lameness affects quality of life.
The luxation is moderate to severe.
Conservative management fails.
Progressive joint damage is occurring.
Surgical Goals
The aim of surgery is to:
Deepen the patellar groove
Realign the quadriceps mechanism
Stabilise the kneecap
Improve joint function
The specific procedure varies depending on the individual dog's anatomy and severity of disease.
What Is the Prognosis After Surgery?
The prognosis following surgery is generally very good.
Most dogs:
Experience significant improvement in comfort.
Regain normal or near-normal mobility.
Return to regular activities.
Post-operative rehabilitation often plays an important role in achieving the best possible outcome.
Can Physiotherapy and Chiropractic Care Help?
Some owners choose to consult a canine physiotherapist or canine chiropractor, particularly when managing mild cases or supporting recovery after surgery.
Physiotherapy is supported by veterinary rehabilitation research and may help improve strength, mobility, and recovery.
Owners should always discuss complementary therapies with their veterinarian to ensure they are appropriate for their dog's specific condition.
Patella Certification and Breeding
Because luxating patella can have a hereditary component, screening breeding dogs is strongly encouraged.
The Orthopedic Foundation for Animals (OFA) maintains a patella certification program in the United States. Veterinarians can assess dogs and submit findings for official certification.
Patella assessments help breeders make informed decisions and contribute to the long-term health of the breed.
Luxating patella is a common orthopaedic condition in Cavalier King Charles Spaniels, but early recognition and appropriate management can greatly improve outcomes.
A dog that occasionally skips, hops, or carries a hind leg may be showing the first signs of a slipping kneecap. Prompt veterinary assessment allows the condition to be graded and treatment options to be explored before significant arthritis and joint damage develop.
Whether managed conservatively or surgically, many Cavaliers with luxating patella go on to live active, happy lives with appropriate veterinary care and ongoing support.
References
Alam, M. R., Lee, J. I., Kang, H. S., Kim, I. S., Park, S. Y., Lee, K. C., Kim, N. S., & Kim, D. Y. (2007). Frequency and distribution of patellar luxation in dogs. Veterinary and Comparative Orthopaedics and Traumatology, 20(1), 59–64.
Bound, N., Zakai, D., Butterworth, S., & Pead, M. (2009). The prevalence of canine patellar luxation in three centres. Clinical and Comparative Orthopaedics, 24(1), 32–37.
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Merck & Co., Inc. (n.d.). Patellar luxation in dogs. In Merck Veterinary Manual. https://www.merckvetmanual.com
Orthopedic Foundation for Animals. (n.d.). Patellar luxation certification program. https://ofa.org
Piermattei, D. L., Flo, G. L., & DeCamp, C. E. (2016). Brinker, Piermattei and Flo's handbook of small animal orthopedics and fracture repair (5th ed.). Elsevier.
Vasseur, P. B. (2003). Stifle joint. In D. Slatter (Ed.), Textbook of small animal surgery (3rd ed., pp. 2090–2133). Saunders Elsevier.
