How Is Arthritis Diagnosed?

By now, you may be wondering:

"My pet is showing several of these signs...so how do veterinarians know it's really arthritis?"

The answer is that diagnosing arthritis isn't based on a single test.

Instead, your veterinarian puts together several important pieces of information—including what you've noticed at home, your pet's physical examination, and, when appropriate, diagnostic imaging—to determine whether arthritis is causing your pet's discomfort.

In many cases, you are the first person to notice something has changed.

The small details you share during your appointment often provide some of the most valuable clues.

It Starts With Your Story

Before your veterinarian even begins the physical examination, they'll want to hear about the changes you've noticed at home.

Questions may include:

• When did you first notice a change?
• Is your pet stiff after resting?
• Does the stiffness improve after walking?
• Has your dog stopped jumping into the car?
• Has your cat stopped climbing the cat tree?
• Are stairs becoming more difficult?
• Have you noticed limping?
• Has your pet become less playful?
• Have there been any previous injuries or surgeries?

These answers help us understand not only whether your pet is painful, but also how that pain is affecting their daily life.

Your Veterinarian's Physical Examination

The physical examination is one of the most important parts of diagnosing arthritis.

Your veterinarian isn't simply feeling your pet's legs.

They're looking for subtle changes throughout the body that often accompany chronic joint pain.

During the examination, your veterinarian may evaluate:

Joint Range of Motion

Healthy joints move smoothly through their normal range of motion.

Arthritic joints often become stiff, painful, or resistant to movement.

Pain

Your veterinarian will gently manipulate the joints to identify areas of discomfort.

Some pets may tense their muscles.

Others may pull the leg away, turn their head, or show subtle signs of discomfort.

Many pets never cry out, even when a joint is painful.

Muscle Loss

One of the biggest clues to chronic arthritis is muscle atrophy.

When a joint hurts, pets naturally use that limb less.

Over time, the surrounding muscles begin to shrink.

Sometimes the muscle loss is much easier to appreciate than the lameness itself.

Joint Thickening

Long-standing arthritis often causes joints to become enlarged.

This happens because of inflammation and new bone formation around the joint.

Walking and Gait

Watching your pet walk is incredibly valuable.

Your veterinarian may observe your pet:

• Walking
• Trotting
• Turning
• Sitting
• Standing
• Climbing a small step
• Rising after lying down

Many arthritic pets move differently than their owners realize because those changes developed gradually over months or years.

Videos Can Be One of Your Best Tools

One of the biggest advantages pet owners have is that you see your pet every day.

Many dogs become nervous during veterinary visits and temporarily hide their stiffness because of adrenaline.

Cats may move very differently in the clinic than they do at home.

That's why I often encourage owners to bring videos.

A short phone video showing your pet:

• Getting up after a nap
• Walking through the house
• Climbing stairs
• Jumping into the car
• Trying to jump onto furniture
• Using the litter box

...can be incredibly helpful and often provides information we can't see during a brief office visit.

Do All Pets Need X-Rays?

Not necessarily.

Many pets with arthritis can be strongly suspected of having joint disease based on their history and physical examination alone.

However, radiographs (X-rays) are often recommended because they help:

• Confirm arthritis
• Evaluate how severely the joint has changed
• Identify previous injuries
• Detect bone spurs
• Rule out fractures, bone tumors, or other conditions that can mimic arthritis
• Help guide long-term treatment decisions

What Can X-Rays Show?

Radiographs allow veterinarians to see changes in the bones surrounding the joint.

Common findings include:

• Bone spurs (osteophytes)
• Narrowing of the joint space
• Thickening of the bone beneath the cartilage
• Joint remodeling
• Evidence of previous injuries
• Joint instability

These changes help confirm that arthritis is present.

What X-Rays Can't Tell Us

This surprises many owners.

The severity of arthritis on an X-ray doesn't always match how painful a pet feels.

Some pets have dramatic arthritic changes and remain surprisingly comfortable.

Others have only mild changes but experience significant pain.

That's because pain comes from inflammation, the joint capsule, surrounding tissues, and changes in how the joint functions—not just what appears on the X-ray.

Your veterinarian treats the patient, not the radiograph.

Are Other Tests Ever Needed?

Sometimes.

If your veterinarian suspects another condition may be causing your pet's lameness or discomfort, additional testing may be recommended.

Depending on your pet's history, this could include:

• Bloodwork
• Joint fluid analysis
• Advanced imaging such as CT or MRI
• Referral to a veterinary orthopedic specialist
• Referral for rehabilitation evaluation

Most pets with typical osteoarthritis never need these tests, but they can be very helpful in more complicated cases.

Why Early Diagnosis Matters

Arthritis is a progressive disease.

The earlier it's recognized, the sooner we can begin breaking the cycle of pain, inflammation, muscle loss, and reduced mobility.

Early treatment doesn't just improve comfort today.

It helps preserve strength, mobility, and quality of life for years to come.