Cruciate ligament (ACL) disease in dogs
The cranial cruciate ligament is the dog version of the human ACL. In dogs it usually weakens slowly and then tears, leaving the knee unstable and painful.
Last updated: October 2026 · 3 sources · see sources
Signs to watch for
- Sudden limping on a back leg
- Sitting with one leg stuck out to the side
- Swelling on the inside of the knee
- Trouble getting up
Trouble breathing, collapse, repeated vomiting, not peeing, or a seizure that lasts more than a few minutes needs a vet right away. See when to see a vet.
How vets diagnose it
Your vet checks the knee for a 'drawer' or tibial thrust movement that shows instability, often under sedation, and takes X-rays. [2][3]
How it's treated
Most medium and large dogs do best with surgery such as TPLO, TTA or a lateral suture. Small dogs are sometimes managed with rest, weight control and rehab. [2][3]
Medicines your vet may mention: Carprofen (Rimadyl), Gabapentin. We don't list doses; your vet will decide what fits your pet.
What it costs to diagnose and manage
| Item | Typical US price | Src |
|---|---|---|
| Diagnosis (exam and tests) | $200–$500 | [1] |
| Treatment, per knee | $3,000–$6,000 | [1] |
These are typical US ranges from the sources listed. Your pet's costs depend on how severe things are, the tests your vet recommends, your pet's size and where you live. Ask your vet for a written estimate.
Outlook
Most dogs return to good function after surgery and rehab. Many dogs tear the ligament in the other knee later. [2][3]
Common questions
What is cruciate ligament (ACL) disease in dogs?
The cranial cruciate ligament is the dog version of the human ACL. In dogs it usually weakens slowly and then tears, leaving the knee unstable and painful.
What are the signs of cruciate ligament (ACL) disease?
Common signs include: sudden limping on a back leg, sitting with one leg stuck out to the side, swelling on the inside of the knee, trouble getting up.
How do vets diagnose cruciate ligament (ACL) disease?
Your vet checks the knee for a 'drawer' or tibial thrust movement that shows instability, often under sedation, and takes X-rays.
How is cruciate ligament (ACL) disease treated?
Most medium and large dogs do best with surgery such as TPLO, TTA or a lateral suture. Small dogs are sometimes managed with rest, weight control and rehab.
How much does cruciate ligament (ACL) disease cost to treat?
Diagnosis (exam and tests): $200–$500; Treatment, per knee: $3,000–$6,000. Costs vary with severity, tests, your pet's size and where you live.
Related
This page is general information for pet owners, not veterinary advice. Talk to your vet about your own pet.