We are not veterinarians, and this is not veterinary advice. Every clinical statement below is attributed to a named veterinary source and linked, so you can check it against the original rather than take our word for it. Where the evidence is genuinely unsettled, we say so instead of picking a side. If your dog is in pain or cannot bear weight, contact a vet today. Last updated 2026-08-19 · How we source our content

Small dogs get cruciate injuries too — but in a Chihuahua the knee story usually has a second character in it, and most pages about "dog ACL tears" never mention them.

The Chihuahua is not on the high-incidence list

The American College of Veterinary Surgeons names Rottweiler, Newfoundland, Staffordshire Terrier, Mastiff, Akita, Saint Bernard, Chesapeake Bay Retriever and Labrador Retriever as breeds with known higher incidence of cranial cruciate ligament disease. These are all medium-to-large dogs.

The Chihuahua is not on that list. But there is a condition this breed genuinely is predisposed to, and it is closely tangled with cruciate disease.

The luxating patella connection

Breeds with short, bowed legs — Chihuahuas, toy poodles, Yorkshire Terriers, Pomeranians, Pekingese — are predisposed to medial patellar luxation (MPL), where the kneecap slips out of its groove (Cornell University College of Veterinary Medicine, VCA).

Patellar luxation has been estimated at around 1.3% of dogs in primary-care practice but rises steeply in predisposed breeds, and small dogs carry roughly twelve times the risk of large breeds, with higher risk in females than males. Heritability has been studied in the Chihuahua specifically, through a Swedish screening programme.

Here is the finding that should change how you read your dog's limp:

Between 45% and 61% of small dogs (under 15 kg) with a cranial cruciate ligament rupture were reported to have concurrent medial patellar luxation. Cruciate disease frequently occurs secondarily to MPL, with higher incidence in more severe grades.

In other words: in a small dog, these two problems travel together. A kneecap that does not track properly changes the mechanics of the joint, and the cruciate ligament pays for it over time.

Why that matters to you

1. The diagnosis needs to cover both. If your Chihuahua is diagnosed with a cruciate tear, ask explicitly: "Is there also patellar luxation, and what grade?" Treating one while ignoring the other is a known route to a disappointing outcome — which is why veterinary literature describes combined surgical approaches addressing both problems in the same procedure for small-breed dogs.

2. The signs can look different from a big dog's. Classic MPL presentation is the intermittent "skip" — a few steps on three legs, then a shake of the leg and back to normal. That skipping gait is not the same as the steady lameness of a cruciate tear, and a dog can show both at different times.

3. Bracing logic is different. A stifle brace addresses cranial tibial translation. It is not a treatment for a luxating kneecap. If your dog's primary problem is the patella, a knee brace is not the matched product — which is the sort of thing a shop with an affiliate link has no incentive to tell you.

Signs to look for

Cruciate-type signs, per VCA Animal Hospitals:

• Sudden lameness, sometimes with no weight on the leg
• "Toe touching" — minimal weight-bearing
• Limping that improves with rest and returns with activity
• Stiffness after lying down
• Sitting with the leg kicked out sideways
• Reluctance to jump up
• Thigh muscle loss on the affected side over time

Patella-type signs to mention to your vet:

• Intermittent skipping or hopping for a few strides, then normal
• Kicking the leg out backwards as if to reset something
• A limp that appears and disappears rather than persisting
• Both back legs affected at different times

A small point that matters: Chihuahuas jump off furniture that is enormous relative to their size, many times a day. If you are managing either condition, that is one of the few things you can change immediately.

Diagnosis

Your vet will check for abnormal forward movement of the tibia relative to the femur using a drawer test or tibial compression test (VCA), and will separately assess whether the patella can be displaced from its groove and graded. Radiographs are common.

In a very small, tense dog these examinations can be difficult while awake, and sedation is sometimes needed for a reliable assessment.

Options

Surgical stabilisation. Techniques are described by the University of Florida Small Animal Hospital. For small breeds, extracapsular stabilisation has historically been a commonly discussed approach, and where both MPL and cruciate disease are present, veterinary literature describes procedures addressing both at once.

Conservative management. Weight control, controlled activity, physiotherapy, pain management, sometimes bracing.

Small dogs are genuinely the group where non-surgical management comes up most often in veterinary discussion — functional stabilisation without surgery is described more frequently for smaller, lighter dogs. That is context for the conversation, not a rule you can apply to your dog from a website. A survey of ACVS Diplomates and primary-care vets found treatment recommendations do differ by dog size, so expect your vet's advice to reflect that.

Find an ACVS board-certified surgeon here.

If bracing comes up

Read our honest assessment of whether dog knee braces are effective first, and be aware of two small-dog specifics:

• Sizing precision matters more. A 1 cm measurement error on a Chihuahua's leg is a far larger proportion of the limb than on a Labrador's. Our measuring guide explains the three measurements and why you take each twice.
• Not every manufacturer makes a genuinely small brace. Some "extra-small" products are scaled-down medium designs that fit toy breeds poorly. Check the actual measurement range, not the size name.

And if the primary problem turns out to be the kneecap rather than the ligament, ask your vet whether a stifle brace is the right category of product at all before you buy one.

Frequently asked

Are Chihuahuas prone to torn ACLs? They are not on the ACVS high-incidence list, which is dominated by large breeds. They are strongly predisposed to medial patellar luxation, and in small dogs cruciate rupture frequently occurs alongside it — 45–61% of small dogs with a cruciate rupture had concurrent MPL in reported figures.

What is the difference between a luxating patella and a torn cruciate? The patella is the kneecap slipping out of its groove; the cruciate is a ligament inside the joint failing. Classic MPL shows as intermittent skipping that resolves in a few strides; a cruciate tear tends toward more persistent lameness. They frequently coexist in small dogs, and only examination can sort them out.

Can a small dog recover without surgery? Functional stabilisation without surgery is discussed more often for smaller, lighter dogs, and treatment recommendations do vary by dog size. Whether that applies to your dog is a judgement for a vet who has examined the joint.

Does a knee brace help a luxating patella? A stifle brace is designed to limit abnormal forward movement of the tibia. It is not a treatment for a kneecap that leaves its groove. Ask your vet what the primary problem is before buying anything.