Dislocated Kneecap in Dogs (Patellar Luxation)
- Occurrence: common
- Location of disease: Legs
When to visit the vet?
Non-urgent see a veterinarian within 2–3 days
If the condition worsens / symptoms persist, consult a veterinarian.
Definition
Patellar luxation, also known as a dislocated kneecap, is an orthopedic condition in dogs where the patella shifts out of its normal groove in the knee joint, which can lead to Pain and Lameness.
Das Wichtigste auf einen Blick
Patellar luxation is a condition in dogs where the kneecap slides out of its normal position, leading to instability of the knee joint. This displacement can occur either inward or outward. Common causes include genetic predispositions and anatomical anomalies, especially in small dog breeds like Yorkshire Terrier and Chihuahua. Injuries and weak ligaments can also increase the risk. Symptoms include Lameness, Pain, and occasional three-legged walking.
Diagnosis is made through a physical examination and imaging techniques such as X-ray 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, physiotherapy and Pain medication may be sufficient, while in more severe cases, surgery is often required to restore normal knee function. Thorough rehabilitation is crucial for recovery after surgery.
Prevention focuses on responsible breeding practices, regular veterinary examinations, 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 for affected dogs.
Ursachen
The patella is a small bone that glides in a groove at the end of the femur. This groove is called the trochlea and is crucial for the stability of the knee joint. The correct positioning of the patella allows for smooth movement of the knee joint, especially when running and jumping. In patellar luxation, the patella shifts laterally out of this groove and can slide either inward (medial luxation) or outward (lateral luxation).
The causes of patellar luxation are diverse. One of the most common causes is a genetic predisposition leading to anatomical anomalies, such as a shallow trochlea or a misalignment of the limb axis. Such genetic factors are particularly common in small dog breeds. Breeds like the Yorkshire Terrier, Chihuahua, and Pomeranian are particularly susceptible. Additionally, external factors such as traumas or leg injuries can also play a role. In larger dog breeds, lateral patellar luxation is more common, while smaller breeds tend to have medial patellar luxation.
Another contributing 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 to other orthopedic conditions, such as a cruciate ligament rupture.
Symptoms
The Symptoms of patellar luxation can vary depending on the severity. In the initial stage, the dog may only show occasional limping, known as a “skip” or “hop”: the dog lifts the affected leg for one or two steps before putting weight on it normally again.
In more advanced cases, the dog may show persistent Lameness that worsens over time. Affected animals may also show signs of Pain, such as Whining or Licking the affected area. In severe luxation, the dog may not be able to bear weight on the leg at all and shows a clear unwillingness to walk or jump.
Another common symptom is a visible deformity or discomfort in the knee area. Some dogs also show signs of joint stiffness, especially after periods of rest. Chronic patellar luxation can also lead to secondary osteoarthritis, which further damages the joint and causes Pain.
Diagnose
The diagnosis of patellar luxation usually begins with a thorough physical examination by the veterinarian. The affected knee joint is manually examined to assess patellar movement. 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 may be taken to visualize the exact position of the patella and possible anatomical anomalies. In some cases, a CT or MRI scan may also be necessary to obtain detailed images of the joint.
The diagnosis also includes an assessment of the severity of the luxation, which is divided into Grades 1 to 4. Grade 1 describes occasional luxation with spontaneous return of the patella to the correct position, while Grade 4 represents permanent luxation where the patella remains constantly outside the trochlea.
Therapie
The treatment of 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 physiotherapy exercises and, if necessary, Pain medication may be sufficient. These measures aim to strengthen the muscles around the knee and reduce joint instability.
In more severe cases (Grade 3 or 4), surgical intervention is often necessary to restore normal knee function. Various surgical techniques can be used, including deepening the trochlea to provide better support for the patella, or repositioning tendons and muscles to correct the direction of the patella’s pull.
Postoperative, comprehensive rehabilitation is necessary, including physiotherapy 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.
Prognose und Nachsorge
The prognosis for dogs with patellar luxation depends on various factors, including the severity of the luxation, the chosen treatment method, and the dog’s response to therapy. With early diagnosis and appropriate treatment, the prognosis is generally favorable, especially for dogs with milder forms of luxation.
Dogs that undergo successful surgical correction often have a good to very good prognosis, with many animals regaining normal or near-normal function of the affected leg. However, the long-term prognosis can be affected by the development of osteoarthritis, particularly in dogs that have already suffered significant joint damage before treatment.
In cases where surgical correction is not possible or not desired, the prognosis can vary. Some dogs may maintain an acceptable quality of life with conservative treatment, while others may experience persistent Pain or Limited mobility.
Prävention
The prevention of patellar luxation often begins with careful breeding practices. Since genetic factors play a significant role in the development of this disease, it is important not to breed dogs with known patellar problems. Breeders should focus on selecting parent animals that are free of patellar luxation to minimize the risk for future generations.
A healthy diet and regular exercise are also crucial to promote general health and the strength of muscles and joints. Overweight can put additional pressure on the joints and should be avoided to reduce the risk of luxation. Regular veterinary examinations can help detect early signs of joint problems and treat them promptly.
For dogs with already mild patellar luxation, preventive measures such as targeted physiotherapy exercises can help strengthen the muscles around the knee and improve joint instability. The veterinarian or a specialized animal physiotherapist can develop individual exercise plans tailored to the dog’s needs.
Ausblick auf aktuelle Forschung
Patellar luxation is a widespread orthopedic problem in dogs, caused by a displacement of the patella from its normal position. This condition can be attributed to both genetic factors and external influences. Current research focuses on better genetic mapping to identify predisposing genes that increase the risk of patellar luxation. These genetic studies are crucial for developing breeding programs that can reduce the incidence of the disease in at-risk breeds.
Additionally, research is exploring innovative surgical techniques and materials to improve knee joint stability in affected dogs. The development of minimally invasive surgical procedures that shorten recovery time and reduce postoperative complications is a current focus. Researchers are also working on improving rehabilitation techniques to maximize leg functionality after surgery.
Another interesting area of research is non-invasive treatment methods, such as physiotherapy and targeted exercises, which can help in 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 therapy protocols that veterinarians can apply in practice.
The role of environmental factors and the lifestyle of dogs are also being intensively investigated to develop preventive measures. Researchers analyze how diet, exercise, and general care influence the risk of patellar luxation. Such insights could lead to comprehensive recommendations for dog owners to minimize the risk of kneecap dislocations.
Overall, current research aims to deepen the understanding of patellar luxation, develop effective prevention strategies, and improve treatment options. These efforts are crucial to enhance the quality of life for dogs with this condition and promote the well-being of the canine population as a whole.
Frequently Asked Questions (FAQs)
1. What is Patellar Luxation?
2. Which dogs are most commonly affected?
3. How is Patellar Luxation diagnosed?
4. What Symptoms does a dog with Patellar Luxation show?
5. What treatment options are available?
6. Is surgery always necessary?
7. What does postoperative care look like after surgery?
8. Can dogs walk normally again after treatment?
9. Can Patellar Luxation be prevented?
10. Should I take my dog to the vet if I suspect Patellar Luxation?
Literatur
- Perry, K. L., & Déjardin, L. M. (2021). Canine medial patellar luxation. Journal of Small Animal Practice, 62(5), 315–335. https://doi.org/10.1111/jsap.13311
- Di Dona, F., Della Valle, G., & Fatone, G. (2018). Patellar luxation in dogs. Veterinary Medicine: Research and Reports, 9, 23–32. https://doi.org/10.2147/VMRR.S142545
- O’Neill, D. G., Meeson, R. L., Sheridan, A., Church, D. B., & Brodbelt, D. C. (2016). The epidemiology of patellar luxation in dogs attending primary-care veterinary practices in England. Canine Genetics and Epidemiology, 3, Article 4. https://doi.org/10.1186/s40575-016-0034-0
- Engdahl, K., Bergström, A., Höglund, O., & Hanson, J. (2023). The epidemiology of patellar luxation in an insured Swedish dog population. Preventive Veterinary Medicine, 220, 106034. https://doi.org/10.1016/j.prevetmed.2023.106034
- Vodnarek, J., Schneider, E., Bockstahler, B. A., & Schnabl-Feichter, E. (2024). Outcome of surgical correction of medial patellar luxation in dogs weighing less than 10 kg. Veterinary Record, 194(8), e3994. https://doi.org/10.1002/vetr.3994
- Eskelinen, E. V., Suhonen, H., Virolainen, J., & Liska, W. D. (2025). Outcome and complications following medial patellar luxation corrective surgery with tibial tuberosity transposition using a locking plate and a pin fixation: 45 unilateral and 20 single-session bilateral procedures. Veterinary and Comparative Orthopaedics and Traumatology, 38, 186–193. https://doi.org/10.1055/s-0044-1795087
- Kim, H.-W., Kim, Y.-S., Kim, W. K., Kang, K.-W., & Kang, B. J. (2024). Medial patellar luxation induces cartilage erosion in dogs: A retrospective study of prevalence and risk factors. American Journal of Veterinary Research, 85(11), Article ajvr.24.07.0190. https://doi.org/10.2460/ajvr.24.07.0190
- Isaka, M. (2022). Positive outcomes after surgical correction of grade IV medial patellar luxation in small breed dogs. Open Veterinary Journal, 12(3), 351–355. https://doi.org/10.5455/OVJ.2022.v12.i3.7