What is Luxating Patella?

Luxating patella is a common knee condition that can affect any dog, but chihuahuas and other small breeds are particularly prone to it.

The patella is the name for a dog’s kneecap and luxating (which means out of place) patella is when the kneecap moves out of its normal position. You might also hear it referred to as a floating kneecap.

The kneecap sits in a groove above the thigh bone, when it slips out of it’s normal position it can only be returned when your chihuahua relaxes his leg, this will give you the tell-tale skip and hop that chihuahuas do when they are running about.

Chihuahuas and other small breed dogs are prone to it and female dogs are more likely to be affected than males.

A luxating patella can be caused by trauma or be a birth defect that might start to show itself once your chihuahua is about four months old.

How to spot it

You may notice:

• Your dog sits with his knees turned outward
• Intermittent limping and hopping when running about
• Pain or swelling around the joint
• Reluctance to jump up or down
• Pain when the joint is manipulated manually.

However, some dogs can live with a luxating patella without significant issues and not all chihuahuas who skip have this problem.

Luxating Patella is graded from 1-4

1. The kneecap slips out from time to time and can be manipulated back into position.
2. The kneecap is more likely to slip out of position and your chihuahua may start to show signs of pain and discomfort.
3. The kneecap stays out of position most of the time and will be impacting on your chihuahuas ability to run about without pain.
4. The kneecap is permanently out of place which will be causing pain and discomfort stopping your chihuahua from using this leg.
5. You may also hear it referred to as a medial or lateral luxating patella. This refers to the direction the kneecap slips in. Medial is when it slips towards the body and lateral is when it slips sideways.

How to treat luxating patella

If your chihuahua has a grade 1 or 2 luxating patella it is likely that managing the situation may be the best option. Keeping his weight down, not allowing him to jump down from high places, supporting his joints with good nutrition, regular exercise and in some cases anti-inflammatories and physio. 

Grade 3-4 condition is more likely to require surgery which involves deepening the groove on the femur, so the kneecap stays in place. If surgery is not performed it could cause cranial cruciate ligament rupture and painful arthritis.

Supporting the condition

As the condition can be genetic it can’t be prevented, but by adding good diet (Not processed kibble) and a range of vitamins and minerals that support collagen renewal can help. It would be a good idea to speak with a dog nutritionist who can give you tailored advice for your dog.

Dog Naturally Magazine suggest a range of exercises to strengthen your dog’s muscles. If the surrounding muscles are strong, then it will help prevent the kneecap from slipping.

• Have your dog move from a Sit to a Stand several times in a row.
• If you have stairs (preferably carpeted), have your dog ascend and descend the stairs three to five times, several times a day. Besides this, you can also find a steep hill and have him walk up and down and zig-zag across the face of the hill.
• Teach your pet to army crawl. Have him get into a down position and slowly lure him forward with some food and encourage him to keep his rear end down.
• Walking over Cavalettis (a series of raised bars set up in a row) will encourage flexion and extension of the stifles.
• Leg weights can be applied above the hock and the dog can go for a walk or do his exercises with them on to provide resistance and improve muscle strength.
• Underwater treadmills or swimming are excellent ways to strengthen the surrounding knee structures. The resistance of the water will help build muscle strength and the buoyancy of the water makes it a safer workout.

Speak to your vet to make sure an exercise regime is appropriate for your chihuahua’s condition.

Buying a puppy

If you are buying a puppy it is a good question to ask the breeder and an excellent reason to buy from a reputable licensed breeder. It is irresponsible to breed from a bitch that has luxating patella in her genetic make-up, and most responsible breeders won’t do this.

A good breeder who is a member of a breed club is going to be familiar with the issues of luxating patella in chihuahuas. They are likely to have had their breeding stock score tested against this condition and you are well within your rights to ask about this before buying. The breeder is going to be more than happy to provide you with the results to the testing if they are good.

You can also get your puppy tested, it can cost anything from 50.00 depending on the complexity of the examination. If your puppy shows a strong likelihood of developing the condition, then you could return her to the breeder.

Caution

If you do get your puppy tested and the results are not in the dog’s favour you might find yourself obliged to advise any insurance company and therefore find yourself not covered. I would discuss this with your vet before you undertake anything. Make sure you are insured and past your warm-up period before you get any advice from the vet.