When your dog suddenly starts limping on their back leg, it can be both alarming and heartbreaking to watch.
One moment they’re running or jumping as usual, and the next they’re struggling to bear weight or refusing to walk altogether.
Sudden limping can range from a simple sprain to something far more serious, like a ligament tear or bone injury.
We outline the common causes of sudden back leg limping in dogs, what you can do at home, and when to seek veterinary help.
Dog Suddenly Limping Back Leg — Why It Happens
A dog may suddenly limp on its back leg due to injury, muscle strain, ligament damage, arthritis flare-ups, or even nerve issues. Sometimes, the cause is temporary—like stepping awkwardly or landing wrong after a jump—but other times, it points to a deeper orthopedic or neurological problem.
Older dogs are especially prone to conditions like arthritis or hip dysplasia, while active breeds may experience ligament tears or muscle pulls.
Sudden limping should never be ignored, as early care can prevent long-term joint damage or chronic pain.
Common Causes of Dog Suddenly Limping Back Leg
1. Soft Tissue Injury or Muscle Strain
Just like humans, dogs can pull or strain a muscle from sudden movement, rough play, or overexertion.
These injuries often cause mild to moderate limping that appears suddenly after activity. Your dog may still bear some weight but seem stiff or reluctant to climb stairs.
While these injuries usually heal with rest, persistent limping or visible swelling may indicate something more severe, like a tendon injury or micro-tear that needs veterinary attention.
Read more: Dog Suddenly Lethargic and Wobbly (What It Really Means)
2. Cruciate Ligament Tear (CCL Injury)
One of the most common causes of sudden back leg limping in dogs is a torn cranial cruciate ligament (CCL)—similar to the ACL in humans.
This ligament stabilizes the knee joint, and when it tears, your dog might suddenly refuse to bear weight on the affected leg. You may also notice swelling around the knee and a “drawer sign” (when the shin bone moves abnormally forward).
CCL tears can happen during running, jumping, or turning sharply. Large breeds like Labradors, Rottweilers, and German Shepherds are particularly at risk. Surgical repair is often necessary for full recovery.
3. Patellar Luxation
In small or toy breeds, a dislocated kneecap (patellar luxation) is a leading cause of sudden limping. The kneecap can slip out of its normal groove, causing a quick hop or skip in the dog’s stride.
Some dogs “reset” it naturally and walk normally after a few seconds, while others experience repeated dislocations that cause pain and inflammation. Chronic luxation can lead to arthritis or ligament tears over time if untreated.
4. Hip Dysplasia or Arthritis Flare-Up
Older dogs and large breeds often experience joint degeneration, especially in the hips and knees.
If your dog suddenly starts limping after rest or exercise, it could be an arthritis flare-up or the early stages of hip dysplasia, where the hip joint doesn’t fit properly in its socket.
The limp may come and go, worsening with cold weather or high activity. Anti-inflammatory medication, joint supplements, and weight control can help manage symptoms, but veterinary diagnosis is essential for proper care.
5. Paw or Nail Injury
Sometimes the problem isn’t deep in the leg—it’s right at the paw. A cut, cracked nail, or lodged object (like a thorn or pebble) can cause sudden limping.
Check your dog’s paw pads and between the toes carefully for debris, swelling, or bleeding. If your dog pulls the leg away, whimpers, or licks the paw excessively, that’s a sign of localized pain.
Cleaning minor wounds and keeping the paw protected often resolves mild cases, but infected or bleeding injuries need vet care.
6. Bone Fracture or Dislocation
If your dog yelps suddenly, refuses to move, or holds one leg up completely, a fracture or joint dislocation could be the cause.
These are typically due to trauma—such as being hit by a car, falling from a height, or landing badly after a jump. Swelling, bruising, and severe pain are telltale signs.
Immediate veterinary attention is critical, as fractures and dislocations can cause permanent damage or internal bleeding if untreated.
Read more: Dog Suddenly Limping Front Leg (When to Worry)
What to Do If Your Dog Is Suddenly Limping on a Back Leg
If your dog starts limping suddenly, first keep them calm and restrict movement to prevent further injury. Avoid walks, running, or jumping until you know the cause.
Next, inspect the paw and leg for visible wounds, swelling, or trapped debris. Clean any minor cuts gently with antiseptic and apply a light bandage if necessary.
For muscle strains or sprains, apply a cold compress wrapped in a towel for 10–15 minutes, two or three times a day, to reduce inflammation. Ensure your dog rests on a soft surface and discourage activity.
If the limp persists beyond 24–48 hours, schedule a veterinary exam. Never give human pain medications like ibuprofen or aspirin, as they can be toxic to dogs. Your vet can prescribe safe pain relief and perform X-rays or joint exams to pinpoint the issue.
When to Call or Visit Your Vet
Contact your vet right away if:
Your dog refuses to bear weight on the leg.
There’s visible swelling, deformity, or an open wound.
The limp appears suddenly after trauma or intense exercise.
Your dog yelps when the leg or hip is touched.
The limping lasts longer than 48 hours without improvement.
For senior dogs or those with arthritis, worsening limping or weakness in the hind legs could signal degenerative joint disease or nerve compression. Early diagnosis is vital for pain management and mobility preservation.
Read more: Dog Wobbly and Not Eating (Possible Causes)
Key Takeaway
Sudden back leg limping in dogs can range from a simple strain to serious orthopedic issues like ligament tears or fractures.
While some causes resolve with rest and time, persistent or severe limping needs prompt veterinary care.
Always observe your dog’s behavior, check for visible injuries, and avoid overexertion until you know what’s wrong. With early intervention, most dogs can recover well and get back to running, jumping, and wagging their tails pain-free.