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Patellar Luxation (Dislocation of the Kneecap) in Dogs

Occurrence: common
Location of illness: Legs

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

Patellar luxation, also known as dislocationA dislocation is the displacement of two bones at a joint, so that they are no longer in their normal position relative to each other. This often leads to Pain, Swelling, and limited movement. of the kneecap, is an orthopedic condition in dogs in which the kneecap (patellaThe patella, or kneecap, is a small, flat bone located in front of the knee joint and embedded in the tendon of the quadriceps muscle. It plays an important role in increasing the leverage of the muscle to extend the knee.) shifts out of its normal gliding groove in the knee joint, which can lead to pain and lameness.

The most important facts at a glance

Patellar luxation is a condition in dogs in which the kneecap slides out of its normal position, leading to instability in the knee joint. This displacement can happen either inward or outward. Common causes include genetic predispositions and anatomical abnormalities, especially in small dog breeds like Yorkshire Terriers and Chihuahuas. Injuries and weak ligaments can also increase the risk. Symptoms include lameness, pain, and occasional three-legged walking.

DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made through a physical examination and imaging procedures such as X-rays to determine the severity of the luxation, which ranges from Grade 1 (mild) to Grade 4 (severe). Treatment depends on the severity. In mild cases, physical therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. and pain medication may be sufficient, while more severe cases often require surgery to restore normal knee function. Thorough rehabilitation is crucial for recovery after surgery.

PreventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. focuses on responsible breeding practices, regular veterinary check-ups, and a healthy lifestyle for the dog. Research focuses on genetic studies to minimize diseases in breeding, as well as innovative surgical techniques and non-invasive treatments to improve the quality of life of affected dogs.

Causes

The patellaThe patella, or kneecap, is a small, flat bone located in front of the knee joint and embedded in the tendon of the quadriceps muscle. It plays an important role in increasing the leverage of the muscle to extend the knee. is a small bone that glides in a groove at the end of the femurFemur is the technical term for the thigh bone. It connects the hip joint to the knee joint and plays a central role in supporting body weight and movement.. This groove is called the trochlea and is crucial for the stability of the knee joint. The correct positioning of the patellaThe patella, or kneecap, is a small, flat bone located in front of the knee joint and embedded in the tendon of the quadriceps muscle. It plays an important role in increasing the leverage of the muscle to extend the knee. allows smooth movement of the knee joint, especially when running and jumping. In patellar luxation, the kneecap shifts laterally out of this groove and can slide either inward (medial luxation) or outward (lateralLateral refers to the side of the body or a body part, as opposed to medial, which describes a position closer to the midline of the body. In veterinary medicine, it is used to describe the location of structures or injuries. luxation).

The causes of patellar luxation are varied. One of the most common causes is a genetic predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases. that leads to anatomical abnormalities, such as a shallow trochlea or misalignment of the limb axis. Such genetic factors are particularly common in small dog breeds. Breeds such as the Yorkshire Terrier, Chihuahua, and Pomeranian are particularly susceptible. In addition, external factors such as traumaA trauma refers to a physical injury or damage caused by external force. Traumas can range from simple cuts to severe multiple injuries. or leg injuries can also play a role. LateralLateral refers to the side of the body or a body part, as opposed to medial, which describes a position closer to the midline of the body. In veterinary medicine, it is used to describe the location of structures or injuries. patellar luxation is more common in larger dog breeds, while smaller breeds are more prone to medial luxation.

Another causal factor can be the general condition of the ligaments and muscles that stabilize the knee. Weak or overstretched ligaments can increase the likelihood of luxation. Insufficient muscle development or strengthening can also contribute to the problem. In some cases, patellar luxation can also occur as a secondary problem in other orthopedic conditions, such as a cruciate ligament ruptureA rupture is a tear or break in an organ or tissue. It can be caused by trauma, illness, or overextension, and often requires medical intervention..

Symptoms

Very common symptoms:

Common symptoms:

Rare symptoms:

Swelling of the Stifle

The symptoms of patellar luxation can vary depending on the severity of the condition. In the initialInitial means beginning or at the start. In medicine, it can refer to the first symptoms of a disease or the first phase of a treatment process. stages, the dog may only show occasional limping, known as a “skip” or “hop”, where the dog lifts the affected leg for one or two steps before putting it back to normal.

In more advanced cases, the dog may show persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. lameness that worsens over time. The affected animals may also show signs of pain, such as whining or licking at the affected area. In severe luxation, the dog may not be able to put any weight on the leg and shows a clear unwillingness to walk or jump.

Another common symptom is a visible deformation or discomfort in the knee area. Some dogs also show signs of joint stiffness, especially after periods of rest. ChronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. patellar luxation can also lead to secondary osteoarthritis, which further damages the joint and causes pain.

Diagnosis

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of patellar luxation usually begins with a thorough physical examination by the veterinarian. The affected knee joint is manually examined to check the mobility of the patellaThe patella, or kneecap, is a small, flat bone located in front of the knee joint and embedded in the tendon of the quadriceps muscle. It plays an important role in increasing the leverage of the muscle to extend the knee.. The veterinarian will try to gently move the kneecap to determine if it easily slides out of the trochlea.

In addition to the physical examination, X-rays of the affected leg can be taken to visualize the exact location of the patellaThe patella, or kneecap, is a small, flat bone located in front of the knee joint and embedded in the tendon of the quadriceps muscle. It plays an important role in increasing the leverage of the muscle to extend the knee. and any anatomical abnormalities. In some cases, a CT or MRI scan may also be necessary to obtain detailed images of the joint.

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. also includes an assessment of the severity of the luxation, which is divided into grades from 1 to 4. Grade 1 describes an occasional luxation with spontaneous return of the patellaThe patella, or kneecap, is a small, flat bone located in front of the knee joint and embedded in the tendon of the quadriceps muscle. It plays an important role in increasing the leverage of the muscle to extend the knee. to the correct position, while Grade 4 represents a permanent luxation in which the patellaThe patella, or kneecap, is a small, flat bone located in front of the knee joint and embedded in the tendon of the quadriceps muscle. It plays an important role in increasing the leverage of the muscle to extend the knee. remains constantly outside the trochlea.

Therapy

Treatment for patellar luxation depends on the severity of the condition and the individual needs of the dog. In mild cases (Grade 1 or 2), conservative treatment with physical therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. exercises and, if necessary, pain relievers may be sufficient. These measures aim to strengthen the muscles around the knee and improve the stability of the joint.

In more severe cases (Grade 3 or 4), surgery is often necessary to restore normal knee function. There are various surgical techniques that can be used, including deepening the trochlea to provide a better hold for the patella, or repositioning tendons and muscles to correct the direction of pull of the patellaThe patella, or kneecap, is a small, flat bone located in front of the knee joint and embedded in the tendon of the quadriceps muscle. It plays an important role in increasing the leverage of the muscle to extend the knee..

Postoperatively, comprehensive rehabilitation is necessary, including physiotherapyVeterinary physiotherapy encompasses a range of treatment methods aimed at improving the mobility and well-being of animals through exercise, massage, and other manual techniques. and controlled movement exercises to promote healing and support the return to normal function. The veterinarian will create a customized rehabilitation plan to optimize the dog’s recovery.

Prognosis and follow-up care

The prognosis for dogs with patellar luxation depends on various factors, including the severity of the luxation, the treatment method chosen, and the dog’s response to therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions.. With early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and appropriate treatment, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. is generally favorable, especially in dogs with milder forms of luxation.

Dogs undergoing successful surgical correction often have a good to very good prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop., with many animals regaining normal or near-normal function of the affected leg. However, the long-term prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. can be affected by the development of osteoarthritis, especially in dogs who have already suffered significant joint damage prior to treatment.

In cases where surgical correction is not possible or desired, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. may be more variable. Some dogs can maintain an acceptable quality of life with conservative treatment, while others may experience persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. pain or limited mobility.

Prevention

PreventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of patellar luxation often begins with careful breeding practices. Since genetic factors play a significant role in the development of this condition, it is important not to use dogs with known patellaThe patella, or kneecap, is a small, flat bone located in front of the knee joint and embedded in the tendon of the quadriceps muscle. It plays an important role in increasing the leverage of the muscle to extend the knee. problems for breeding. Breeders should pay attention to the selectionSelection refers to the process of natural or artificial selection of specific individuals for reproduction, based on desired genetic traits. In breeding, this is applied to promote specific characteristics in dogs and cats. of parent animals that are free of patellar luxations in order to minimize the risk for future generations.

A healthy diet and regular exercise are also crucial to promote the overall health and strength of the muscles and joints. Overweight can put additional pressure on the joints and should be avoided to reduce the risk of luxation. Regular veterinary check-ups can help detect early signs of joint problems and treat them in a timely manner.

For dogs who already have mild patellar luxation, preventive measures such as targeted physical therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. exercises can help strengthen the muscles around the knee and improve the stability of the joint. The veterinarian or a specialized animal physiotherapist can develop individual exercise plans tailored to the needs of the dog.

Outlook on current research

Patellar luxation is a widespread orthopedic problem in dogs, caused by a displacement of the kneecap from its normal position. This condition can be attributed to both genetic factors and external influences. Currently, research is focused on better genetic mapping to identify predisposing genes that increase the risk of patellar luxation. These genetic studies are crucial to develop breeding programs that can reduce the occurrence of the disease in at-risk breeds.

In addition, research is investigating innovative surgical techniques and materials to improve the stability of the knee joint in affected dogs. The development of minimally invasiveInvasive describes medical procedures or pathogens that enter the body or penetrate tissue. In medicine, invasive procedures can range from minimally invasive techniques to open surgery. surgical procedures that shorten recovery time and reduce postoperativePostoperative refers to the time after a surgical operation. This phase includes recovery and the management of possible complications after the procedure. complications is a current focus. Researchers are also working to improve rehabilitation techniques to maximize the functionality of the leg after surgery.

Another interesting area of research is non-invasive treatment methods, such as physical therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. and targeted exercises, which can help with mild cases of patellar luxation. Studies show that targeted muscle training and weight management can significantly alleviate symptoms in certain dogs. Research in this area aims to develop standardized therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. protocols that veterinarians can use in practice.

The role of environmental factors and the lifestyle of dogs is also being intensively studied to develop preventive measures. Researchers are analyzing how diet, exercise, and general care affect the risk of patellar luxation. Such findings could lead to comprehensive recommendations for dog owners to minimize the risk of kneecap dislocations.

Overall, the goal of current research is to deepen the understanding of patellar luxation, develop effective preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. strategies, and improve treatment options. These efforts are crucial to increase the quality of life of dogs with this condition and to promote well-being in the dog populationIn veterinary medicine, the term population refers to a group of animals of a particular species living in a specific geographic area or environment. as a whole.

Frequently asked questions (FAQs)

What is a patellar luxation? A patellar luxation is a condition in which the kneecap (patellaThe patella, or kneecap, is a small, flat bone located in front of the knee joint and embedded in the tendon of the quadriceps muscle. It plays an important role in increasing the leverage of the muscle to extend the knee.) shifts out of its normal position in the knee joint. This can lead to pain, lameness, and limited mobility. It is one of the most common orthopedic problems in dogs.
Which dogs are most commonly affected? Small dog breeds such as Yorkshire Terriers, Pomeranians, and Chihuahuas are most commonly affected by patellar luxation. However, large breeds can also be affected, especially if genetic factors play a role.
How is patellar luxation diagnosed? Patellar luxation is usually diagnosed by a physical examination and, if necessary, X-rays. The veterinarian will examine the dog’s knee joint for signs of instability and abnormal movement.
What symptoms does a dog with patellar luxation show? Symptoms can include lameness, a hopping of the affected leg, pain, and occasionally swelling in the knee area. Some dogs may only show occasional problems, while others are constantly affected.
What treatment options are there? Treatment depends on the severity of the luxation. In mild cases, physical therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. and weight management may be sufficient. In more severe cases, surgical intervention may be necessary to restore normal knee function.
Is surgery always necessary? Not necessarily. In mild cases, conservative treatment may be sufficient. Surgery is usually recommended if the luxation is recurrentRecurrent refers to a disease that repeatedly returns or worsens after a temporary remission or improvement. or causes severe pain.
What does postoperativePostoperative refers to the time after a surgical operation. This phase includes recovery and the management of possible complications after the procedure. care look like after surgery? After surgery, the dog needs rest and restricted movement to promote healing. Physical therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. and special exercises may also be part of the rehabilitation plan. The veterinarian will give specific instructions to support recovery.
Can dogs walk normally again after treatment? Many dogs recover completely and can walk normally again after treatment or surgery. The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. depends on the severity of the luxation and the treatment method chosen.
Can patellar luxation be prevented? While genetic factors cannot be changed, a healthy lifestyle, including a balanced diet and regular exercise, can help reduce the risk. Genetic counseling may be helpful for at-risk breeds.
Should I take my dog to the vet if I suspect patellar luxation? Yes, it is important to see a veterinarian if you suspect patellar luxation. Early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and treatment can help reduce long-term damage and pain.