Luxating Patellas in Bernese Mountain Dogs

Medial luxation, where the kneecap slips toward the inside of the leg, is the classic small-breed pattern. It is associated with a shallow groove and with the limb alignment typical of toy breeds, and it is what most articles on the subject describe.

Lateral luxation, where the kneecap slips outward, is the pattern more often seen in large and giant breeds. It tends to be linked to differences in hip and femoral alignment rather than to the knee alone, and in a large dog it frequently exists alongside other orthopaedic problems rather than in isolation.

That second point is the practically important one for a Bernese. Hip dysplasia is on this breed's documented health issue list, and so is elbow dysplasia and arthritis. A kneecap that tracks poorly in a dog whose hips are also poor is part of a chain, not an isolated fault, and treating only the knee often disappoints.

There is also a mechanical reality that changes the calculation. Grading systems for patellar luxation run from one to four, and a grade that a fifteen pound dog carries through life without difficulty can be a functional problem in a dog of 70 to 115 pounds, simply because there is so much more force running through the joint. Severity of signs and grade on examination correlate loosely in small dogs and more tightly in large ones.

Finally, chronic patellar instability wears cartilage, and it also predisposes to cruciate ligament rupture, which in a dog this size is a surgical problem with a long recovery.

The grade determines the conversation. Low grades in a large dog are usually monitored with attention to weight and muscling; higher grades are surgical discussions.

If you think your Bernese has luxating patellas, the plan is three steps: write down what you have seen and when it started, book a veterinary appointment rather than waiting for the next flare, and take video of the behaviour or symptom before you go — the thing you are worried about rarely happens in the consulting room. Screening in the parents covers hip dysplasia, elbow dysplasia, bloat (gdv).

What the vet visit should produce is a diagnosis and a written plan, not just reassurance: what is being ruled out, what the monitoring interval is, and which signs mean you come back sooner. Ask what the treatment costs across a year rather than per visit, because that is the number that decides whether you are managing this condition or reacting to it.

Between appointments, keep a short log — dates, what you saw, what changed. It is the single most useful thing an owner brings to a follow-up, and for luxating patellas it is often what separates a clear pattern from a guess.