Why is my dog limping on a back leg?
The most common causes of hind-leg limping in dogs, which ones need a vet today, and what recovery usually involves.
Updated August 12, 2026 · 9 min read
The short version
- A sudden hind-leg limp after play is most often a cruciate ligament injury.
- A limp that comes and goes over weeks points toward arthritis or hip dysplasia.
- Non-weight-bearing lameness, swelling, or crying out is a same-day veterinary visit.
- Most causes are managed, not cured. Rehab is how function comes back.
Start by watching how the limp behaves
Before anything else, note three things: whether the dog puts any weight on the leg, whether the limp is worse after rest or after activity, and whether it appeared suddenly or crept in.
A limp that is worst on rising and eases after a few minutes of walking is the classic arthritis pattern. A limp that appears mid-run and does not improve is an acute injury until proven otherwise.
The most common causes in the hind leg
Cranial cruciate ligament (CCL) rupture is the single most common cause of hind-leg lameness in adult dogs. It is the canine equivalent of an ACL tear, and it frequently affects the other leg within a couple of years.
Hip and elbow dysplasia, lumbosacral disease, patellar luxation, and simple soft-tissue strain make up most of the rest. In older large-breed dogs, bone tumours are uncommon but serious enough to be worth ruling out with radiographs.
When to go in today
Go the same day if the dog will not bear any weight, if the leg is visibly swollen or at an odd angle, if there is a wound, if the dog cries when the leg is touched, or if both hind legs are weak.
Sudden hind-limb weakness with a hunched back or dragging toes can be a spinal cord problem. That is an emergency, not a limp.
What treatment usually looks like
Diagnosis comes first: an orthopedic exam, often sedated, plus radiographs. From there the plan is either surgical or conservative.
Surgical cases, most full CCL tears in medium and large dogs, go to TPLO or a similar procedure, then into a rehabilitation program to rebuild the muscle lost during recovery.
Conservative cases get pain control, weight management, activity modification, and a rehab program. In both paths, structured rehab is the difference between a dog who limps less and a dog who uses the leg again.
What rehab actually does
A dog with a painful leg stops using it within days, and the muscle disappears fast. Rehab reverses that deliberately: controlled loading, balance work, and progressive strengthening for the exact muscles that shut down.
Underwater treadmill work is common early because water reduces how much weight the limb carries. Land exercise, manual therapy, and a home program take over as strength returns.
Common questions
- Can a limp resolve on its own?
- A mild soft-tissue strain often does within a few days of restricted activity. A limp lasting more than 48 hours, or any non-weight-bearing limp, needs an exam.
- Is it safe to give my dog human pain medication?
- No. Ibuprofen, naproxen, and acetaminophen are toxic to dogs. Pain control needs to come from your veterinarian.
- How long does rehab take after a cruciate surgery?
- Most programs run eight to twelve weeks, starting within a week or two of surgery, with the home program continuing beyond that.
This guide is general information, not veterinary advice. Diagnosis and treatment decisions belong with your veterinarian.