CONDITION
Patellar Luxation
Patellar luxation describes a kneecap that moves out of its normal position in the groove at the front of the thigh bone. In dogs, this can happen as a brief slip that resolves on its own, or as a more persistent displacement. The underlying cause may be developmental (related to the shape and alignment of the leg bones as the dog grows) or may follow injury. Owners often notice a sudden hop or skip in one back leg during a walk, sometimes followed by the leg returning to normal a few strides later. In other cases, a pet may carry one leg for longer periods, or move with a persistently altered gait. The pattern can be intermittent or constant, mild or more limiting, and may involve one leg or both. This page explores what those patterns can signal, the structural factors that allow the kneecap to move, how the condition is examined and graded, and the range of approaches (from monitoring and supportive care to surgical correction) that exist depending on severity, comfort, and the functional impact on the individual animal.
Why this matters now
Patellar luxation is common in small and toy breed dogs, and signs generally start before 1 year of age. In a study of dogs attending first-opinion practices in England, 1.3% had a diagnosis, with the highest breed figures in Pomeranians (6.5%), Yorkshire Terriers (5.4%) and Chihuahuas (4.9%). Miniature and toy Poodles are listed as predisposed in other sources. The condition also occurs in larger breeds. Inward (medial) luxation is still the more common direction in large dogs, but outward (lateral) luxation is seen more often in large breeds than in small ones.
Many dogs live with mild patellar luxation throughout their lives without significant problems. However, the abnormal tracking can lead to progressive cartilage wear and osteoarthritis over time. Dogs with more severe grades may experience increasing lameness and joint deterioration. Some dogs that initially had occasional luxation may develop more frequent or permanent displacement as supporting structures stretch.
Signals & patterns
Early signals
Intermittent skipping or hopping gait
Dogs may hold up a back leg for a few steps then resume normal walking as the kneecap pops back into place.
Occasional yelping during activity
A sudden vocalisation may occur when the kneecap dislocates, particularly during jumping or turning.
Preference for holding one leg up briefly
Owners may notice the dog periodically lifting a hind leg, then continuing normally.
Kicking the leg out behind
Dogs sometimes extend the affected leg backward, which may help the kneecap return to its groove.
Later signals
More frequent or constant lameness
As the condition progresses, episodes may become more frequent or the kneecap may remain out of position.
Bunny hopping gait
Dogs may move both back legs together rather than alternating normally, particularly when running.
Decreased activity or reluctance to jump
Joint discomfort and instability may lead to reduced exercise tolerance and avoidance of certain movements.
Visible changes in leg conformation
Over time, dogs with severe luxation may develop bowed legs or rotational changes in limb alignment.
Click to read about the biological mechanisms
How this is usually investigated
Diagnosis of patellar luxation typically combines physical examination with imaging to assess severity and plan any intervention.
Orthopaedic examination
Gait analysis
Radiographs
Assessment of other joints
Options & trade-offs
Management depends on the grade of luxation, clinical signs, and individual circumstances. Not all cases require surgical intervention.
Monitoring and conservative management
Observation, weight management, and controlled exercise for dogs with mild disease and minimal symptoms.
Trade-offs: Appropriate for lower-grade luxation with infrequent or no lameness. Regular monitoring helps identify progression requiring reassessment.
Joint supplements and physical therapy
Nutritional support for joint health and exercises to strengthen supporting muscles.
Trade-offs: May help maintain joint function and comfort. Does not address the underlying anatomical problem but can support joint health.
Surgical correction
Various procedures to deepen the groove, realign structures, and stabilise the kneecap.
Trade-offs: Typically recommended for grades II to IV with clinical signs, while grade I and some grade II cases are usually managed without surgery. Multiple techniques exist; the approach depends on specific abnormalities present.
Pain management
Anti-inflammatory medications or other analgesics when needed for comfort.
Trade-offs: Provides symptomatic relief. Long-term use requires monitoring. Does not address progression of underlying joint changes.
Common misconceptions
"Patellar luxation always requires surgery"
Many dogs with lower-grade luxation live comfortably without surgical intervention. Treatment decisions depend on functional impact and progression, not grade alone.
"The skipping gait is just a quirky behaviour"
The characteristic intermittent hopping typically indicates the kneecap temporarily moving out of position. This is a structural issue rather than a behavioural choice.
"Small dogs naturally have leg problems"
Whilst patellar luxation is common in certain breeds, it represents a genuine orthopaedic condition rather than a normal variant. Breeding programmes can reduce prevalence.
Related conditions
Hip Luxation
Hip luxation describes displacement of the hip joint, a different joint luxation that shares the underlying concept of a bone moving out of its normal position within a socket or groove. Owners observing sudden lameness or altered gait may consider both patterns, though the location and mechanisms differ.
Meniscal Injury of the Stifle
Meniscal injury can occur in the same stifle joint as patellar luxation, usually alongside cranial cruciate ligament injury, and these concurrent injuries are looked for when the knee is assessed. Both conditions affect the knee and can contribute to lameness, discomfort, and changes in how the hind leg moves.
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Iliopsoas Strain
Iliopsoas strain involves injury to a deep hip flexor muscle, and dogs compensating for patellar luxation may alter their gait in ways that place unusual load on the iliopsoas or other muscle groups. Both conditions can cause hind-limb lameness and reluctance to engage in certain movements.
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Intervertebral Disc Disease (IVDD)
Intervertebral disc disease affects the spine rather than the knee, but it can also change how the back legs move. Disc disease tends to cause back pain, a wobbly hind end or crossing hind feet, whereas patellar luxation typically causes a skipping lameness that resolves within a few steps. Telling the two apart needs a hands-on orthopaedic and neurological examination.
Cruciate Ligament Disease in Dogs
Cranial cruciate ligament rupture is reported alongside patellar luxation in 13% to 41% of dogs, depending on the study and the size of dog, so both are checked for when the knee is examined. The two conditions can cause overlapping hind-leg lameness and altered gait.
Tracking how often limping episodes occur and what activities trigger them provides useful context. Noting whether symptoms are becoming more frequent or severe over time helps guide discussions about management. Maintaining a healthy body weight reduces stress on joints, and understanding what movements cause problems can help adapt daily activities.
Last reviewed: 10 October 2026 · Dr Alastair Greenway MRCVS