To get a clear picture of what patellar luxation is, let's understand the anatomy of the knee and the role of the patella. 

The patella is a small, flat, triangular bone located in front of the knee joint and its purpose is to protect the more fragile structures within the joint and assist in the transfer of forces during movement.
It is embedded in the tendon of the quadriceps muscle group that is responsible for extending the leg and when your dog moves about the patella glides up and down a groove at the lower end of the thigh bone (femur), allowing for smooth and efficient movement.

​​​In a normal healthy dog, the patella stays within this groove as the leg moves, maintaining stability and proper alignment of the knee. However, in the case of a luxating patella, the patella shifts out of its groove.

Understanding the causes and contributing factors is crucial for effective management and treatment, ensuring that affected dogs receive the appropriate care to maintain their comfort and mobility. Here are a few common factors that  contribute to the occurrence of a luxating patella:

Genetic Predisposition
Small-breed dogs due to inherited anatomical abnormalities like a shallow groove in the femur or abnormal limb conformation have a higher chance of developing patellar luxation. Though it is less common it doesn't mean that mixed & large breed dogs are immune to this condition.

Trauma
Traumatic injuries can lead to the kneecap moving out of its usual position. Sudden falls, collisions, overexertion or engaging excessively in high-impact activities or even sudden, forceful twisting or rotational movements of the leg can cause the patella to dislocate making it more prevalent in active & agile breeds that participate in athletic/ sporting activities

Obesity Muscle Weakness
Excessive body weight and weak thigh muscles (quadriceps) or imbalanced muscle development around the knee can contribute to the patella's misalignment. The patella relies on well-developed and balanced muscle strength to stay in its proper position during movement. Muscle weakening might happen due to the lack of exercise, aging, natural degeneration or poor nutrition especially during the growing years.

Joint laxity
Lax joints or loose joints make it easier for the patella to move out of its position. While some dog breeds are genetically predisposed to having loose joints, injury to soft tissues, and developmental abnormalities also result in a loose joint capsule.

Hormonal influences
Hormonal imbalances, particularly those related to estrogen and testosterone, can affect the patellar ligament and tendon strength, potentially contributing to the development of patellar luxation.

Secondary to other orthopedic conditions
Luxating patella can be secondary to other orthopedic issues, such as hip dysplasia or cruciate ligament injuries. The presence of these conditions may alter joint mechanics and lead to a patellar misalignment.:

In Patella Luxation the kneecap can move out of it's place in two different directions.

Lateral Patellar Luxation: When the patella moves towards the outside of the knee joint i.e. the kneecap dislocates or slips to the outer side of the femoral groove, which is the groove on the end of the thigh bone (femur) where the it is known as a lateral patellar luxation

Medial Patellar Luxation: In the case of a medial patellar luxation, the patella moves towards the inside of the knee joint. This means that the kneecap dislocates or slips to the inner side of the femoral groove.

​From here a luxating patella is classified into different grades based on its severity:

The kind and severity of symptoms vary based on the grade of patellar luxation.  Dogs with mild luxation may exhibit only subtle signs, while others with a more severe luxation may show more pronounced symptoms.

​While the luxation can occur in the front and hind legs- it is most commonly seen in the hind legs or the stifle joint which is very similar in function to the human knee joint. Here are some common signs to watch for:

Lameness and Skipping: Lameness or a noticeable limp, especially after physical activity is one of the most common symptoms. They may also show an intermittent skipping motion while walking or running, which occurs when the patella temporarily dislocates and then returns to its normal position.

Difficulty or Reluctance to Bear Weight on the Affected Leg: Dogs with patellar luxation may express difficulty in putting weight on the leg with the affected knee by avoiding that leg altogether or having a noticeable favour of one leg over the other

Pain and Swelling: Patellar luxation also causes pain and discomfort causing your dog to yelp or even get aggressive when the knee is touched or manipulated. In some severe cases, this discomfort can be visible in the form of swelling around the affected area. it is also common for the affected area to be warmer than the rest of the body.

Bunny-hopping: A bunny-hopping motion is commonly observed in dogs with joint issues. Bunny-hopping is when a dog uses both their hind legs simultaneously to move about instead of the usual alternating stride like a rabbit. This motion helps them distribute the pressure of the affected limb to the unaffected one.

Extra Attention: Dogs may give the joint extra attention and excessively lick or chew at the affected area to soothe the area.

Do not wait for any significant clinical signs, if your dog is experiencing discomfort or mobility issues momentarily, it is crucial to seek veterinary evaluation and diagnosis. Early detection allows for effective management of the condition that can greatly improve your furry friend's quality of life.

​Your Vet will probably perform a physical examination and might use imaging tools like X-rays, CT scans, or MRIs to accurately diagnose if your dog has a luxating patella

Treatment options for luxating patella in dogs can vary depending on the severity of the condition and the individual dog's specific needs. Here are some common approaches according to the grade of luxation. 

Grade I cases often don't require surgical intervention, as the patella can manually be moved back into place and a conservative management route is often suggested which usually involves:

Weight Management and Exercise Regulation: Maintaining a healthy weight is crucial for dogs with a luxating patella, as excess body weight can put additional stress on the affected joint. Your veterinarian may recommend a balanced diet and controlled exercise to manage weight and reduce strain on the joints.

Medications for Pain Relief and Inflammation: Non-steroidal anti-inflammatory drugs (NSAIDs) or other pain medications may be prescribed to alleviate discomfort and reduce inflammation in the knee.

Physical Therapy and Strengthening Exercises: Physical therapy, such as targeted exercises and controlled movement, can help strengthen the muscles around the knee, providing better support and stability.

Some Grade II cases may be managed conservatively like in Grade I, but if lameness and discomfort persists, surgical treatments might be considered along with conservative measures.

Trochleoplasty is generally considered for a Grade II luxating patella. It involves reshaping the groove on the femur where the patella rests in order to enhance the patella's stability and reduce the risk of dislocation.

Grade III cases usually requires surgical intervention due to the frequent and more severe luxations.

​Patellar luxation surgical treatments like, tibial tuberosity transposition may be performed where the attachment site of the patellar tendon on the tibia is realigned to improve joint mechanics. Trochleoplasty may also be performed.

Grade IV cases almost always necessitate surgical treatment due to the permanent and severe displacement of the patella.

Surgery is required to realign the structures, reconstruct the joint, and stabilize the patella. Along with Tibial Tuberosity Transposition and Trochleoplasty, Medial Patellar Luxation (MPL) Surgery is also another surgical option that aims to correct the abnormal alignment of the knee joint and stabilize the patella in its proper position. The surgeon may deepen the femoral groove, release tight tissues, or tighten loose tissues to ensure the patella stays in place.

​Femoral Varus Osteotomy (FVO) is another procedure used to correct patellar luxation and certain dysplasia conditions in dogs. It involves realigning the femur by angling it inward (varus) to improve joint stability and reduce pressure on the knee and hip joints. FVO is recommended for dogs with concurrent femoral deformities and patellar instability.

After surgical intervention, rehabilitation is crucial to aid in the dog's recovery and return to normal function. Rehabilitation programs may include controlled exercises, hydrotherapy, massage, and other modalities to improve muscle strength, joint mobility, and overall healing.

​Regardless of the chosen treatment approach, physical therapy exercises and regular follow-up visits with a veterinarian are essential for the successful management of the condition.  

It's essential to remember that the treatment approach for patellar luxation is not solely based on the grade but also takes into account the dog's overall health, activity level, and any other concurrent orthopedic conditions. And even if the decision of surgical correction is opted for, adding conservative treatment methods into the mix can greatly improve the success of surgery and increase the rate of recovery.

But the real question lies in "how much does luxating patella surgery cost?" Surgical correction is suggested for more severe cases to restore normal alignment quickly and the costs do tend to be higher and can be greatly influenced by your location with cities being more expensive.

If the condition requires just conservative treatment, the cost is generally more reasonable and affordable but with the duration of the treatment being longer- the costs can add up.

If surgery is performed before the development of arthritis or another knee injury, the prognosis is usually very good allowing your dog to regain full use of their leg. However, if in case arthritis has already developed in the knee joint, your dog may experience intermittent pain in the leg and it may progress even after surgery.

That said, patellar luxation surgery doesn't guarantee that the luxation won't happen again. Prescription anti-inflammatories, joint supplements, and the diet may slow the progression of arthritis and help control any discomfort. Weight reduction is also recommended for overweight dogs.