What X-Rays Miss… And Why That Matters for Dogs on Librela and Cats on Solensia

Let’s start with a simple idea.

X-rays do not always tell us the full story.

There is a great paper by Jones and colleagues that helps set the stage for this. It looks at dogs with elbow disease and compares what we see on X-rays to what is actually happening inside the joint.

You can read the Jones article here: https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2022.789898/full

What the Jones Paper Teaches Us

Sometimes X-rays look mild, but the joint damage is actually severe.

And sometimes X-rays look severe, but the cartilage damage inside the joint is not as bad as expected.

In other words, X-rays are helpful, but they are not perfect.

X-rays  are great for showing bone, but they do not show cartilage very well. They also cannot fully show inflammation, early damage, or subtle changes inside the joint.

So, if we only rely on X-rays, we can miss important diseases.

That is the key takeaway.

Why I Often Recommend CT Scans

This is exactly why, in my practice, I often recommend CT scans when we are trying to fully understand a joint problem.

CT gives us a much more detailed, 3D view of the joint.

It allows us to better see and evaluate small bone fragments, joint incongruity, and subtle structural changes that may not show up on standard X-rays.

Based on what the Jones paper highlights, we know that relying only on X-rays can lead us to underestimate how much disease is really present. CT helps close that gap.

It also doesn’t show cartilage perfectly either, but it gives us far more information about the joint than X-rays alone.

Now Let’s Build on That with the Farrell Paper

A second paper helps take this one step further.

You can read the Farrell article here: https://pubmed.ncbi.nlm.nih.gov/24393075/

This study looked at a large number of Labrador Retrievers with elbow disease. The researchers compared X-rays to what they saw during surgery when they looked directly at the cartilage.

What They Found

In general, worse X-rays did mean worse cartilage damage.

So, there is a relationship.

But here is the important part: Even dogs with mild X-ray changes sometimes had severe cartilage damage inside the joint.

As the X-ray score (used in the research paper)  increased, the chance of severe damage goes up. But severe damage can still exist even when X-rays do not look that bad.

So again, X-rays do not tell the whole story.

Why This Matters for Librela and Solensia

Now, let’s connect this to newer arthritis treatments like Librela in dogs and Solensia in cats.

These medications can reduce pain very effectively. Dogs and cats feel better. They move more. Everyone is happy.

But here is the concern: If joint disease is progressing faster in some patients, and we already know that X-rays can miss or underestimate disease, then we may not recognize a problem early enough.

This concept does not just apply to dogs, it applies to cats as well.

Compared to dogs, cats are often harder to assess for pain and mobility changes. They hide discomfort very well. So, if disease is progressing and we are relying on X-rays alone, we may be even more likely to miss what is really happening.

Putting It All Together

The Jones paper teaches us that X-rays are limited.

CT can help us see more, especially when the clinical picture and imaging do not match.

The Farrell paper shows us that even when X-rays look mild, real damage inside the joint can be severe.

When we combine that with powerful pain relief from drugs like Librela and Solensia, we have a situation where disease can progress quietly and rapidly. The pet feels better. The X-rays may not look terrible early on. But the joint may still be getting worse.

Final Thoughts

This is why we have to be careful about relying too much on any one tool.

X-rays are helpful, but they are only one piece of the puzzle.

CT, clinical exam, history, and function all matter.

And as we use newer medications that change how dogs and cats feel and move, understanding these limitations becomes even more important.

Because sometimes, what we do not see is the most important part.