Academy · Conditions
Patellar luxation in dogs: symptoms, grades and treatment
When the kneecap slips out of its groove, the dog often hops a few steps on three legs and then carries on as if nothing had happened.
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What is patellar luxation in dogs?
In patellar luxation, the kneecap slips out of its groove on the thigh bone, usually towards the inside of the knee. Small breeds are mainly affected. Typically, the dog hops a few steps on three legs and then walks on normally. Depending on the grade and symptoms, the condition is either monitored or treated surgically.
At a glance:
- What: the kneecap (patella) slips out of the groove on the thigh bone, usually inwards (medially)
- Affected: mainly small breeds; in a study of primary-care practices in England, patellar luxation was recorded in around 1.3% of dogs.
- Typical: brief hopping on three legs, followed by normal walking
- Classification: usually four grades, from occasionally to permanently luxated
- Treatment: conservative or surgical depending on the grade; the prognosis is usually good
In detail
How common is patellar luxation in dogs?
In primary-care small animal practices in England, around 1.3% of dogs had patellar luxation. Eleven breeds, including the Pomeranian and the Yorkshire Terrier, were affected more often than crossbreeds. Dogs that weighed less than the average for their breed had a higher risk (O’Neill et al. 2016).
How can I recognise it?
- Sudden hopping, with the leg briefly held up
- The dog stretches the leg backwards until the kneecap pops back into place
- With higher grades, persistent lameness or a bow-legged stance
- If both sides are affected, often just a noticeably stiff gait at the back
What do the four grades mean?
| Grade | Findings |
|---|---|
| 1 | The kneecap can be pushed out of the groove by hand and returns on its own |
| 2 | It occasionally slips out on its own and stays out until it slides back or is pushed back |
| 3 | It is mostly out of the groove but can be pushed back by hand |
| 4 | It is permanently out of the groove and cannot be pushed back |
How is patellar luxation treated in dogs?
Treatment of patellar luxation depends on the grade, the symptoms and any concurrent conditions. Not every patellar luxation needs surgery. With low-grade changes and no or only mild symptoms, conservative measures such as weight management, adapted exercise and targeted muscle building can be useful at first. These measures can support joint function but do not correct the anatomical cause of the luxation. With recurrent lameness, higher-grade luxations or marked functional limitations, surgery may be indicated. Depending on the findings, options include deepening the groove (trochleoplasty), transposing the attachment of the patellar ligament (tibial tuberosity transposition) or correcting bony malalignment.
Other stifle conditions can also occur, including ruptures of the cranial cruciate ligament. Such findings are taken into account when planning treatment (Di Dona et al. 2018).
What role does objective gait analysis play in patellar luxation?
Because the kneecap often only luxates intermittently, lameness is not always visible during a short veterinary examination. Sensor-based gait analysis can be used as a complement to document selected movement parameters such as stance and swing phase duration, movement asymmetries and ranges of motion. Repeated measurements under comparable conditions make it possible to follow changes in gait during treatment or rehabilitation. A study by DiGiovanni et al. (2023) examined post-operative progress in dogs with patellar luxation using objective stance analysis. The results illustrate the potential benefit of quantitative measurement methods but cannot be transferred directly to kinematic analysis with LupoGait. Gait analysis therefore complements the clinical examination but does not replace orthopaedic diagnostics.
O’Neill DG, Meeson RL, Sheridan A, Church DB, Brodbelt DC (2016). The epidemiology of patellar luxation in dogs attending primary-care veterinary practices in England. Canine Genetics and Epidemiology 3:4. doi:10.1186/s40575-016-0034-0
Di Dona F, Della Valle G, Fatone G (2018). Patellar luxation in dogs. Veterinary Medicine: Research and Reports 9:23–32. doi:10.2147/VMRR.S142545
DiGiovanni LC, Roush JK, Berke K (2023). Preoperative and postoperative stance analysis in dogs with patellar luxation confirms lameness improvement after surgery. American Journal of Veterinary Research 84(3). doi:10.2460/ajvr.22.10.0186
Frequently asked questions
No. It depends on the grade, the symptoms and the dog’s age. The decision is made by the vet.
Yes, it is often congenital or develops during growth. Unusual hopping in a puppy should be checked by a vet.
A hereditary predisposition is considered likely, especially in small breeds. For breeding, it makes sense to have the parent dogs examined.
Recognise patellar luxation. Document changes in movement.
Patellar luxation can change a dog’s gait intermittently or permanently. Alongside the clinical examination, objective gait analysis can help to document selected movement parameters and follow changes during treatment or rehabilitation.