What is Kneecap Dislocation?
A patellar luxation occurs when your dog’s kneecap is dislocated or slides out of its normal position. Dislocated kneecaps are usually due to a congenital defect, but can also be the result of trauma. This condition is the most common in young, small, or toy breeds, including:
- Yorkshire Terrier
- Boston Terrier
- Jack Russell Terriers
- Miniature Poodles
Certain large breed dogs are also predisposed to the patellar luxation, especially if they suffer from hip dysplasia. Treatment alternates according to the severity, or grade, of the luxation, but the prognosis is typically good.The kneecap can dislocate for a variety of reasons, usually because of a congenital defect that prevents the patella from staying seated in its groove. Many cases of patellar luxation are mild and do not require surgical treatment, though, in more severe or persistent cases, surgery will be needed to prevent future complications.
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Symptoms of Kneecap Dislocation in Dogs
Symptoms of patellar luxation vary according to the severity of the condition and include:
- Limping or lameness
- Reluctance to place weight on the limb
The clinical signs are often intermittent and sudden. Your dog may exhibit an irregular gait for a few steps, usually with one limb raised from the ground, before resuming a normal walk.
There are two types of patellar luxation in dogs: medial and lateral:
- Medial luxation, which is the more common form, occurs when the dog’s joint slips towards the opposite leg. This prevents the dog from extending its knee normally though often times the kneecap will slide back into position by itself after a few steps.
- With lateral luxation, the kneecap slips to the outside of the leg, away from the body. This form of patellar luxation tends to impact the dog more severely and is more common in large breed dogs, where hip problems may lead to misaligned bones in the legs.
Causes of Kneecap Dislocation in Dogs
Patellar luxation transpires when the kneecap slips out of the groove in which it normally sits. This groove is shallower in many small or toy breed dogs, such as Chihuahuas, Maltese, and Yorkshire terriers, resulting in a genetic predisposition for the condition. A kneecap can also become dislocated as a result of trauma, and there has been a rise in occurrences in larger dogs, including Akitas, Boxers, and Golden Retrievers.
Diagnosis of Kneecap Dislocation in Dogs
Most cases of patellar luxation in small dogs are diagnosed early on when the puppy begins to show irregularities in its gait. If the kneecap is dislocated at the time of your office visit, the veterinarian can easily diagnose the condition with a physical examination of the affected limb. The diagnosis can be confirmed via x-rays, which also help determine the extent of the condition and reveal the shape of the bones.
Patellar luxation is often graded based on severity, with levels ranging from 1 to 4. With grade 1 luxation, the kneecap sits normally but can luxate under slight pressure because of the shallowness of the groove. Grades 2 and 3 are more severe though the joint can typically still be replaced manually. A luxation is classified as grade 4 if the joint sits outside of the groove at all times and will not stay seated if replaced. Treatment depends on the severity of the luxation, so it is important that the veterinarian receives enough information to grade your dog’s condition appropriately.
Treatment of Kneecap Dislocation in Dogs
Treatment varies according to the grade that the veterinarian diagnoses.Supportive Treatment
If your dog is diagnosed with grade 1 luxation, surgery is not recommended. Instead, you can help prevent the kneecap from sliding out of place with regular exercise and supportive nutrients. It's critically important to reduce stress exerted on the knee by ensuring that your dog is at a proper weight for its size, and strengthen the muscles surrounding it through daily exercise. Nutritional supplements, such as glucosamine and chondroitin, provide support to the joint and its surrounding tissues.Surgical Treatment
Surgery is usually recommended for luxated patellar graded 2 or above and is necessary for grade 4. There are different types of operations available though the goal is always to replace the kneecap to it's suggested, normal position and prevent future slipping. This can be accomplished by deepening the groove in which the patella sits or by tightening the joint capsule to prevent slippage. In more severe cases, the leg bones may need to be rotated back into the correct position as part of treatment.
Recovery of Kneecap Dislocation in Dogs
Most dogs recover fully once the kneecap has been replaced though you will need to restrict your dog’s activity until the surgical site has healed. Provide a quiet place where your dog can rest, and make sure that it doesn’t bite or chew at the incisions. If the veterinarian prescribed antibiotics as a preventative measure against infection, be sure to administer the full course.
Your dog will most likely begin to use the affected leg again in one to two weeks following surgery. If your dog is still reluctant to place weight on the leg several weeks after treatment, contact the veterinarian, and ask how you can retrain your dog to use that leg. Follow-up exams may be necessary, depending on the treatment. In all cases, continue to monitor your dog for signs of a displaced joint, as the condition may recur or arise in a different knee.
Kneecap Dislocation Questions and Advice from Veterinary Professionals
My Newfie is 1yr., 5 months old. Still growing. Weight is approx. 105 lbs. She has patellar luxation (which began about 3 weeks ago). It only occurs when she is rough housing with our other dog. Question: How is the grade of patellar luxation determined? Is it determined via x-ray? If she is Grade 1 or 2, is there a brace that could be used until she finishes growing?
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Hello. I would appreciate a second opinion. My toy poodle was diagnosed with a grade 1 luxating patella when I took him in for his first ever vet visit as a puppy. He is now 2.5 years old. Over the time I've had him, he's only had 1 or 2 occasions where he holds his leg up like you would if you had a cramp. He recovered almost instantly and was fine.
A couple days ago during his before-bed pee break, he was running in the back yard when he suddenly yelped. He held his right rear leg up and for the next hour before bed, he was walking gingerly on it, not wanting to put a lot of weight on it. Sometimes he would run on it and seemed fine. Almost like he never hurt it. As a precaution, I took him to the vet the next day. I noticed in the morning that he was still walking gingerly on his affected leg and limping a little. After talking with my vet, I opted to crate rest my dog rather than do surgery. The vet graded his luxating patella at a 2 on both knees. He also said that it was not progressed far enough that my dog needed immediate surgery. If his condition doesn't improve within the 2 weeks, then we're probably looking at surgery.
We're on day 2 after the event and when I do let him walk around for potty time, he seems to be walking on his affected knee ok. Sometimes he limps, sometimes he doesn't. I've been reading online that some recommend crate rest like we're doing, and some say crate rest is the worst thing you can do. Basically that's it better to strengthen the muscles instead by keeping up normal activity. What is your opinion on this?
Also, if/when we do opt for surgery, should we do both knees or just the one? This is a cost consideration and also it's me not wanting to have to put him under more than we need to. When he was neutered, he didn't recover so well. It took him about 6-8 hours to be back to normal. He was groggy and lost control of his bladder. Both knees are a grade 2. I've also read that doing both knees at the same time makes the recovery harder/longer.
There are various possible factors which may contribute to patellar luxation and the primary underlying cause would determine whether cage rest is warranted or not; but in most cases cage rest is best. The different factors affecting a patellar luxation include: ligament laxity, angular deformity of the hind limb, rotation of the femur, malformation of the tibia, deviation of tibial crest, shallow groove or tightness / atrophy of quadriceps muscle (this is where cage rest isn’t recommended if the muscle is atrophied). Surgical correction is normally performed for grades II or more; approach to surgery would be at the examining Surgeon’s discretion to determine the most appropriate procedure to achieve the best result including whether to correct one or both knees at the same time. Regards Dr Callum Turner DVM
I forgot to ask...how useful are glucosamine and chondroitin to prevent the kneecap from popping out?
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I have a 8 year old chihuahuas. I am almost positive her knee cap has moved out of place. It has done this once before about 7-8 months ago. But it also went back in place by the the end of the day. It happened again sat and has yet to go back. I have tried to stretch her leg gently to put back in but hasn't helped. She doesn't seem to be in any discomfort. I took her to the vet before but it had already gone back in but he told me she needed surgery to fix ($3800). Several weeks later I took her to the vet i used to work for (6 hours away) and he tried to pop the knee out to see how loose it was and he couldn't get it to go. He said she didn't need surgery now at least. So I guess my question is, if her knee won't go back in by itself, does that mean she will need the surgery?
It looks like the patella luxation is infrequent, so if your Veterinarian is able to manually manipulate it back surgery may not be immediately necessary; however, if there is more laxity or the luxation becomes more frequent, then surgery may be indicated. This problem is common in smaller breeds. I would visit your Veterinarian to see if it can be manually placed back. Regards Dr Callum Turner DVM
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I just purchased a 3 months old white pomeranian puppy few days ago, and I found her walking funny when we brought her home. She loves to run and play, but she looks like she is wabbling.We took her to the hospital and took x rays. Doctor said she has luxating patella grade 3-4, but she may get better since she is only 3 months. My older dog had surgery for patella, and I thought patellas always get worse, never better. Are there possibilities For her to get better, since she is so young?
With cases of patellar luxation, as with many orthopaedic conditions, it is always best to allow the dog to grow (as long as the condition isn’t causing unnecessary pain or additional damage) more before attempting surgical correction. Some mild cases, grade 2 or 3, may improve but if the grade is 3 or 4 I would imagine that surgical correction would be required. Below is a link to the American College of Veterinary Surgeons page on patellar luxation with some interesting information and images. Regards Dr Callum Turner DVM
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My dog had his knee slip out tonight twice. It went towards his other knee or leg. He's a large bread Alaskan malamute 115 pounds. He's in good condition muscle and body wise he's not fat at all just a big dog. I know rehab is a good thing I'm just worried if it's a severe tear. Would you recommend me just trying rehab first or to just make an appt Ik the surgery is pricey that doesn't bother me. I just feel horrible for my dog.
Patellar luxation is a condition that typically affects small dogs, but larger dogs are being affected too; normally patellar luxation in smaller dogs travels towards the other knee and in larger dogs travels away from the other knee, although there are exceptions. Patellar luxation occurs when there is laxity in one of the ligaments surrounding the knee; depending on severity and the size of the dog, different treatment by be attempted. I would recommend visiting your Veterinarian to grade the luxation and to recommend a treatment or surgical plan. Regards Dr Callum Turner DVM
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