Summary

Patellar luxation is a common orthopaedic condition in dogs, especially smaller breeds. It occurs when the kneecap (patella) slips out of its normal position. This condition can lead to pain and lameness and may require surgical treatment in severe cases. This article explains the causes, symptoms and treatment options for patellar luxation in dogs.

Temporary dislocation of the kneecap is a common condition in many patients. small dog breeds. The symptoms are usually not very severe, but can worsen over time. The condition is categorised into four different degrees of severity. Although occasional patellar dislocation without severe symptoms does not necessarily require surgery, surgery is recommended in some cases.

Causes of patellar luxation

Miniature or dwarf dogs (Chihuahuas, Yorkshire Terriers, French Bulldogs, etc.) are particularly affected by this disease. The reason for this lies in a Misalignment of the rear feet. While large dogs usually have very straight hind legs, dwarf breeds have a more or less pronounced curvature of the femur and tibia bones, which often leads to bowed legs. Due to the position of the leg axis, the muscle pull on the patellar tendon pulls the kneecap inwards, which can cause it to pop out inwards.

Medial dislocation (displacement to the inside of the knee) is the most common form. Even if there is an outward pop-out. An accident with damage to the ligament structures can also be a cause of patellar luxation. Recognising the symptoms Normally the owner will notice occasional lameness (walking on 3 legs at times). Only in cases of traumatic patellar luxation (more common in large dogs) are lameness and pain during manipulation very pronounced. Sometimes the diagnosis is an accidental finding.

Degrees of dislocation in patellar dislocation

During the examination, the severity of the dislocation is categorised into 4 levels:

Grade I:
The patella is in its normal position, but can be pushed out of the groove by manipulation when the knee is fully extended and returns to its normal, unsupported position. Clinical symptoms are rare.

Grade II:
The patella dislocates spontaneously when the knee is extended or can be pushed out of its normal position and then remains in this position. This leads to typical temporary lameness. It returns to its original position after some time or by manipulation of the knee joint. Slight limb deformities, such as internal rotation of the tibia, may be observed. If the patella is dislocated, the foot is stretched to differentiate between grade II and III.

Severe degrees that require surgery:

Grade III:
The kneecap is permanently dislocated (immobile), but can be pushed back into its normal position manually. If the dislocation is on one side, the affected foot is constantly relieved. If both sides are affected, the lameness is not so noticeable, but the steps are rather short and the knees are flexed. There is a pronounced internal rotation of the tibia. A poorly developed, flat rolling ridge is often recognisable.

Grade IV:
The patella is permanently dislocated and can no longer be pushed back into its original position manually. The gait is very stiff. The tibia is clearly turned inwards and the crest of the coil is often flat.

Mechanism of patellar dislocation

To better understand the mechanism of patellar luxation in dogs, it is important to know the anatomy of the knee joint. The knee joint consists of three main structures: the thigh bone (femur), the shin bone (tibia) and the kneecap (patella). The kneecap is a small, flat bone that lies in a groove at the end of the thigh bone and is held in place by tendons and ligaments.

The main function of the patella is to act as a lever that transfers the force of the large thigh muscle (quadriceps) to the tibia. This allows the dog to flex and extend the knee joint, which is necessary for normal movements such as running, jumping and climbing.

A patellar luxation occurs when the kneecap slips out of its normal position in the groove on the thigh bone. This can occur either medially (inwards) or laterally (outwards). Medial patellar luxations are more common in small dog breeds, while lateral patellar luxations are more common in larger breeds.

The mechanism of patellar dislocation can be divided into four main categories:

1. Anatomical factorsMalformation or weakness in the structures that hold the kneecap in place, such as tendons, ligaments or bones, can cause the kneecap to slip out of position more easily.
2. Traumatic factorsInjuries, such as knocks or falls, can damage the structures in the knee joint and cause a patellar dislocation. A sudden impact or unusual strain on the leg can cause the kneecap to slip out of its groove.
3. Degenerative factorsLong-term signs of wear and tear in the knee joint, such as osteoarthritis or inflammation, can impair the stability of the kneecap and increase the risk of patellar dislocation.
4. Functional factors: Uneven loads or tension on the knee joint, as can occur with excess weight or misalignment of the legs, can make the kneecap more prone to slipping out of position.

Patellar luxation can lead to pain, swelling and restricted movement, as the normal function of the knee joint is impaired. Over time, this can lead to further damage to the knee joint, such as degenerative changes or osteoarthritis.

Symptoms and diagnosis

The disease can usually be adequately diagnosed during the examination. Even if the diagnosis can be made by palpation alone, it is advisable to take an X-ray. On the one hand, osteoarthritis can be detected, which occurs when the disease has been present for a long time. On the other hand, other differential diagnoses can be ruled out and the degree of deformity recognised. In the case of particularly severe deformities, a computerised tomography scan may be useful in order to measure the bone deformity precisely and plan any necessary bone adjustments.

Symptoms of patellar luxation in dogs

The most common signs of patellar luxation in dogs are

1. LamenessThe dog limps or has difficulty walking. This can occur suddenly or worsen over time.
2. PainDogs with a patellar luxation may show pain in the affected knee. They may be sensitive when the leg is touched or moved and may have difficulty standing up or lying down.
3. SwellingThe affected knee joint may be swollen and warm, especially if the patellar dislocation was caused by an injury.
4. Irregular movementsDogs with a patellar luxation may show unusual movements, such as holding the leg in a twisted position or lifting and lowering the leg while walking.

Here is an example video of a patellar luxation in a dog:

Treatment options - Patellar dislocation therapy

For slight dislocations (Grade 1 and possibly grade 2), surgery is not always necessary. For occasional pain, painkillers can be given temporarily and rest is advisable. Some dogs with mild symptoms grow old without the owner noticing the condition.

The conservative treatment options of patellar dislocation:

1. weight management:

• Importance: Being overweight increases the strain on the joints. A reduction in body weight can significantly alleviate the symptoms of a patellar luxation.
• Realisation: This can be achieved through a combination of a low-calorie diet and regular exercise. We often work closely with the vet to create a personalised diet plan.

2. physiotherapy:

• Target: Improvement of muscle strength, joint mobility and general fitness.
• Methods: This includes exercises to strengthen the muscles around the knee joint, joint mobilisation and special movement exercises.
• Significance: Physiotherapy can help to stabilise the knee and reduce the likelihood of further dislocations.

3. hydrotherapy:

• Concept: Exercise in the water, such as swimming or running on an underwater treadmill.
• Advantages: The water provides resistance and promotes muscle strengthening while relieving pressure on the joints.
• Use: Particularly useful for dogs that have difficulty with normal movement due to pain or weakness.

4. pain management:

• Medication: Non-steroidal anti-inflammatory drugs (NSAIDs) can be used to relieve pain and inflammation.
• Caution: Long-term use of NSAIDs should be under veterinary supervision to avoid side effects.

5. supplements:

• Food supplements: Glucosamine and chondroitin can help support joint health.
• Effect: They help to preserve cartilage tissue and can support joint function.

6. changes in everyday life:

• Adjustments at home: Non-slip mats and ramps can help to avoid unnecessary stress on the knee.
• Movement management: Avoid activities that put a lot of strain on the knee joint, such as jumping or jerky movements.

7. regular monitoring:

• Veterinary checks: Regular visits to the vet are important to monitor progress and adjust the treatment strategy if necessary.
• Long-term perspective: Conservative treatments often require a long-term commitment and, if used correctly, can significantly improve the dog's quality of life.

Surgical therapy

For more frequent pain or dislocations, severe lameness and patellar luxations second or higher degree surgery can lead to a significant improvement in quality of life. Typically, several techniques are combined during the operation - which Treatment methods is there?

Surgical treatment is necessary for dogs with grade 2 (when conservative measures are not sufficient), grade 3 and grade 4 patellar luxation. Surgery may involve different techniques depending on the severity of the condition and the individual circumstances of the dog:

1. Sulcoplasty: Deepening of the sliding groove (sulcus) in the knee joint to keep the kneecap in a better position.
2. Tibial tuberosity transposition: The attachment point of the patellar tendon on the tibia is moved to correct the direction of pull of the tendon and prevent the kneecap from popping out.
3. Lateral fascia retraction: Tightening of the outer joint capsule and the ligamentous apparatus to keep the kneecap in a better position.
4. Repositioning osteotomy: Correction of axial misalignments of the bones in order to distribute the load on the joint evenly and prevent the kneecap from popping out.

The best therapies are those that surgically restore the correct relative position of the kneecap and thigh. This means that the attachment of the right patellar ligament is released using a piece of leg bone and moved either outwards or inwards so that the kneecap is once again correctly positioned over the groove in the thigh. The sawed-off piece of the lower leg is fixed in place with a so-called tensioning strap (two metal pins, wire). In addition, the guide groove of the kneecap on the thigh is deepened using a wedge or block technique. This makes it less easy for the kneecap to jump out of the groove. The bone incisions are secured with soft tissue fixation. The prognosis is very good. Sometimes loose nails have to be pulled out later.

Our patellar luxation surgery method - rapid luxation

This is a surgical procedure in which the kneecap is moved back in the natural direction of movement of the kneecap. A saw cut is the first step in order to be able to move the ball-and-socket joint. A rapid luxation implant is then screwed into the saw cut, initially on one side. The ball joint can now be moved downwards with millimetre precision using the special quick release. At the same time as the pestle, the doctor can now move the leg and control the direction of movement of the kneecap. As soon as the patella bends, optimum patella correction is achieved.

The surgeon then screws the appropriate spacers under the implant and closes the wound. The advantage of the Rapid Luxation method lies not only in the stability and accuracy of the correction, but also in the possibility of subsequent corrections, even in the post-operative phase, as long as the bone has not yet grown in. The following video explains the rapid luxation operation:

After patellar luxation surgery - aftercare and rehabilitation

After the operation, you should six weeks long at the Lead the line. During this time, the patient should not jump, run or play so that the bone can grow properly. Finally, an X-ray check-up is recommended after this period. The prognosis after this operation is generally good. However, it worsens with particularly severe deformities of the hind legs and with a 4th degree dislocation.

After the operation, appropriate aftercare and rehabilitation is required for the dog. The most important measures include

• Pain management with suitable medication
• Restricted activity for 6 to 8 weeks to support the healing process
• Physiotherapy to promote joint mobility and strengthen the muscles
• Regular check-ups with the vet to monitor the healing progress

Often occur Cruciate ligament rupture and patellar luxation occur together and can be treated in one operation.

As a rule, cover Surgery pet insurance policies do not cover this type of procedure - please check with your insurance company beforehand.

Frequently asked questions FAQs on patellar luxation in dogs

Prognosis and prevention

The prognosis for dogs with patellar luxation is generally good, especially if the condition is recognised and treated early. However, in dogs with severe deformities or grade 4 patellar luxation, the prognosis may be less favourable.

To minimise the risk of patellar luxation in dogs, breeders should ensure that only healthy animals with good leg and knee anatomy are used for breeding. In addition, the following measures can help to minimise the risk of patellar luxation in dogs:

• Avoiding obesity: An appropriate diet and regular exercise can help your dog to maintain his ideal weight and thus reduce the strain on his joints.
• Regular check-ups at the vet: Early detection of signs of patellar luxation enables timely treatment and potentially prevents more serious problems.
• Appropriate exercise and training: Dogs prone to patellar luxation may need to be protected from extreme exercise or jumping to reduce the risk of luxation.

It is important to note that some dogs can develop a patellar luxation despite all precautions. In such cases, it is crucial to follow your vet's instructions regarding treatment and aftercare closely to give your dog the best possible prognosis.

To summarise, canine patellar luxation is a common orthopaedic condition that requires timely diagnosis and treatment. Through regular visits to the vet, a healthy lifestyle and appropriate preventative measures, dog owners can help to reduce the risk of patellar luxation in their dogs and maintain the quality of life of their four-legged friends.