Sudden lameness in dogs: what to check before the vet

In 30 seconds

Sudden lameness traces back to trauma in roughly 80 percent of cases in young and medium-aged dogs. The one question that drives everything: is the dog bearing weight or not? If the leg hangs and the dog puts nothing on it, that is an emergency. If the dog bears weight but limps, you have time for a first exam at home. And if your dog is a senior, do not assume "arthritis": a sudden limp in an older dog is sometimes osteosarcoma.

The critical question: weight-bearing or not?

The dog will not bear weight (holds the leg up, never touches the ground)

Non-weight-bearing lameness is almost always an emergency. Likely causes:

Fracture
Joint dislocation (elbow, hip, knee)
Complete tendon or ligament rupture
A deep foreign body
A serious bite wound
A painful tumor

Get to the emergency clinic the same day.

The dog bears some weight but limps

Partial weight-bearing lameness gives you room to investigate. Likely causes:

A minor sprain
A grass awn or foreign body in a paw pad
Small muscle strain
The first flare of a chronic joint process triggered by exertion
Local inflammation

You can usually wait until the next day if the dog is otherwise bright and normal.

The home exam, step by step

Do this with your dog lying comfortably on its side. Your goal is to locate where it hurts, not to diagnose.

1. The paw pads and the spaces between the toes

Look at the top and the underside. Any cut, scrape, grass awn, or thorn?
Check between the toes, where grass awns lodge most in spring and summer.
Press each pad. Does the dog react to one in particular?

2. The nails

Any nail broken, split, or bleeding?
A torn nail hurts a lot and produces an obvious limp.

3. Up the leg: the joints

Start at the joint farthest from the body and work up. For each joint, flex and extend gently, then palpate with care.

Front leg	Hind leg
Carpus (wrist)	Tarsus (hock)
Elbow	Stifle (knee)
Shoulder	Hip

Do you feel crepitus, a gritty or sandy sensation under your fingers? Any swelling, heat, or pain when you press?

4. The long bones

Run moderate pressure along the radius, ulna, and humerus (front leg), and the tibia and femur (hind leg). Is there one spot that triggers a sharp pain response?

5. The muscles

Palpate the muscle groups of the thigh, upper arm, and forearm. Any tightness, heat, or asymmetry side to side?

6. The spine and pelvis

If the lameness is in a hind leg and you find nothing in the leg itself, check the pelvis (pressure over the hips) and the lower spine (pressure over the bony bumps along the back).

Common causes by age

Puppies and juveniles (under 1 year)

Panosteitis (growing-pain bone soreness): intermittent lameness that shifts from leg to leg, in large breeds during growth. It resolves on its own with maturity.
Osteochondritis dissecans (OCD): in the shoulder or elbow, in large breeds. A persistent limp that worsens with exercise.
Hip or elbow dysplasia: covered in its own article.
Trauma from rough play.

Adults (1 to 7 years)

Cranial cruciate ligament rupture: the most common cause of sudden hind-leg lameness in adult dogs. It tears often during abrupt twisting movements. Expect a non-weight-bearing or strongly marked hind-leg limp.
Meniscal injury (with or without a cruciate tear).
Sprains, tendinitis, and muscle strains from overexertion.
A grass awn or foreign body in a paw pad.

Senior (7 years and up)

Established osteoarthritis that flares after exertion. For day-to-day management of an older dog with arthritis, an orthopedic memory-foam bed and a vet-recommended joint supplement help ease morning stiffness and slow the progression.
Osteosarcoma (above all in large and giant breeds). A persistent limp that does not improve within a week in a large, older dog warrants an X-ray, no excuses.
Spondylosis and disc problems.
Cumulative soft-tissue injuries.

The "trot in a straight line" test

Once you have palpated the area, let your dog walk and trot in a straight line on a firm, flat surface. Watch for this:

What you see	What it suggests
Head goes up when a front leg lands	Lame on that front leg
Head drops when a front leg lands	Lame on the opposite front leg
One hind leg "sinks" more with each step (hip asymmetry)	Lame on that hind leg
The stride shortens on one leg	Pain in that leg
A bunny-hop gait in both hind legs	Possible dysplasia or bilateral cruciate rupture

What to do while you decide

Strict rest. No dog parks, no running, no jumping onto the couch. Only short leash walks to potty.
Cold pack (a cold compress wrapped in a cloth) for 10 to 15 minutes over the area if there is swelling.
Do not give anti-inflammatories without a veterinary prescription. Human painkillers like ibuprofen and acetaminophen are toxic to dogs.
If the lameness lasts more than 48 to 72 hours or gets worse, book a vet appointment without waiting longer.

When it is an immediate emergency

A leg hanging with no weight on it.
Open or visibly bleeding wounds.
Intense acute pain (yelping, defensive snapping from pain).
Suspected fracture (visible deformity, clear crepitus).
Lameness after a car hit or a fall from height.
Rapid, hot swelling of a joint.

What to check

Whether the dog bears weight or not.
Whether you have examined the pads and the spaces between the toes.
Whether there is one specific spot that hurts when touched.
Whether this is a senior dog with lameness lasting more than a week (means X-ray).