Luxating Patella

A luxating patella is a condition where the kneecap (patella) dislocates or moves out of its normal position in the trochlear groove at the end of the femur (thigh bone). Most commonly, this is a ‘medial’ luxating patella, where the kneecap dislocates in the direction of the inner leg. However, a ‘lateral luxating patella’ is also possible, where the direction of dislocation is towards the outer leg. This condition can cause discomfort and mobility issues for your dog, commonly a ‘skipping lameness’ where the dog will hold the leg up for several steps before appearing to walk or run normally again. The condition is usually congenital (present at birth) but can also develop at an older age due to injury or other factors. Luxating patella can affect any dog breed but is most common in small and toy breeds such as Pomeranians, Chihuahuas, Yorkshire Terriers, Miniature Poodles, Shih Tzus, etc.

Diagnosis of a luxating patella is usually possible through physical examination by a vet. X-rays are generally needed for presurgical planning and sometimes to aid diagnosis. In some cases, we may advise a CT scan to assess the shape of your dog’s leg in more detail. See our ‘CT Scan’ page for more information about what is involved.

Luxating patella can be graded in severity 1 – 4:

Grade 1: The kneecap can be manually luxated out of position when pressure is applied but does not luxate spontaneously. This is usually an incidental finding during the examination and does not cause any lameness or discomfort. Grade 2: The kneecap spends the majority of time in the correct anatomical position but will spontaneously luxate out of position during leg movement. Grade 3: The kneecap spends the majority of time in a luxated position but will spontaneously return to the correct anatomical position during leg movement. Grade 4: The kneecap is permanently luxated and cannot be manipulated into the correct anatomical position.

The decision to perform surgery will be based on our examination and discussion with you. However, we typically recommend surgery for all grade 3 and 4 luxating patellas and any grade 2 luxating patellas causing frequent or significant mobility issues.

We offer a fixed cost for patella surgery of £1019* (plus the cost of x-rays, if not previously taken at Animal Trust - £419; or the cost of CT in the few cases this is required - £1019). The exact surgical approach is decided on a case-by-case basis.

However, the procedure typically involves:

• Tibial tuberosity transposition (TTT) involves cutting part of the tibia (shin bone) to realign the patella into a straighter position. The bone is held in place with some metal implants, usually 1 or 2 pins and a wire.
• Deepening of the trochlear groove in which the patella should sit. This is known as a ‘sulcoplasty’
• Tightening of the joint capsule (‘imbrication’)
• It is incising through nearby tissues that may contribute to the luxation. This is commonly known as ‘medial release’.
• Corrective alignment of the femur (thigh bone). This is usually only necessary for very severe cases to straighten the bone and prevent luxation of the patella. This is not commonly performed and would not fall under our standard set cost for patella surgery.

*Please note this set cost applies to the vast majority of luxating patellas we see; however more severe or complex cases may need a more involved and bespoke surgical treatment, which will not fall within this set cost

Recovery

Following surgery, your dog will need strict rest, ideally in a dog crate for 2 – 4 weeks. They can go out for short periods (5-10 minutes) of controlled lead exercise 3 – 4 times daily during this time. Following this, we recommend gradually increasing lead exercise over several weeks. The typical recovery time for the majority of dogs is around 12 weeks. Physiotherapy or hydrotherapy may be beneficial during this period. We only routinely take further X-rays during recovery if we are worried that recovery is not as expected.

In a small number of cases, the metal implants may irritate the tendons or muscles, and we may recommend their removal after the bone has healed in its new position.