A sudden yelp, a limp that doesn’t go away, or your dog holding up a back leg—these can be early signs of something more serious than just a pulled muscle. One of the most common orthopedic injuries in dogs is a torn ACL—or more accurately, a torn cranial cruciate ligament (CCL). This ligament plays a crucial role in stabilizing your dog’s knee, and when it’s damaged, it can lead to pain, inflammation, and long-term joint issues if left untreated.

At Animal Hospital Southwest in Fort Worth, we know how hard it is to see your dog in pain. That’s why we’ve put together this guide to help you recognize the signs of a torn ACL, understand your options, and feel confident about your dog’s recovery journey.

For an in-depth clinical overview, check out this Canine Cruciate Ligament Injury resource.

What Is a Torn ACL in Dogs, Exactly?

In dogs, the cranial cruciate ligament (CCL) functions much like the ACL in humans—it keeps the knee joint stable during movement. When this ligament tears, even partially, your dog may experience sudden pain, limping, and joint instability. Without treatment, it can lead to chronic discomfort and degenerative arthritis.

How Do Dogs Tear Their ACLs?

ACL injuries can happen in an instant or develop slowly over time. Here are the most common scenarios:

  • Sudden injuries from jumping, turning quickly, or slipping during play.
  • Chronic wear and tear, especially in older or large-breed dogs.
  • Obesity, which puts extra strain on joints and can speed up ligament degeneration.

If you’re noticing changes in your dog’s movement or posture, this guide on dog limping is a great place to start.

What Does an ACL Tear Look Like in Dogs?

You know your dog best. If something feels off, trust your instincts—here’s what to watch for:

  • Sudden limping or refusal to put weight on a back leg
  • Stiffness after resting or trouble getting up
  • Swelling around the knee
  • A subtle “toe-touching” stance, where the dog avoids full weight-bearing

Some ACL tears are partial, which means symptoms may come and go. Complete tears tend to cause constant lameness and more obvious joint instability. Left untreated, a torn ACL can also lead to problems in the opposite leg as your dog compensates.

How We Diagnose a Torn ACL

At Animal Hospital Southwest, diagnosis starts with a hands-on orthopedic exam:

  • We’ll check for the classic “drawer sign”—an abnormal movement in the knee. This might require sedation.
  • We’ll watch your dog walk to assess their gait and weight-bearing.
  • X-rays are used to rule out other injuries and check for joint swelling or arthritis.
  • In some cases, ultrasound or MRI may be needed to assess soft tissue damage more closely.

Want a closer look at the process? Here’s a detailed overview of canine cruciate ligament diagnostics.

Treatment Options: What Comes Next

Non-Surgical Management

For smaller dogs or those with limited activity levels, non-surgical care can be effective. This approach includes:

  • Strict rest for 6–8 weeks
  • Weight loss if needed
  • Joint supplements like glucosamine, chondroitin, and omega-3s
  • Physical therapy to support surrounding muscles

You can explore non-invasive rehab options here: Rehabilitation Therapies for Animals. This typically is not a good option for medium or large breed dogs.

Surgical Solutions

Surgery is usually the best option for active or medium-to-large dogs. It helps restore stability and reduces the risk of arthritis down the line.

TPLO (Tibial Plateau Leveling Osteotomy)

This procedure changes the angle of the knee joint, eliminating the need for the torn ligament.

TTA (Tibial Tuberosity Advancement)

Also alters knee mechanics, though in a different way than TPLO.

  • Good for active, large-breed dogs
  • Recovery: 12–16 weeks with rehab

Extracapsular Repair (Lateral Suture)

Uses strong sutures outside the joint to mimic the ligament’s role.

  • Best for small or sedentary dogs
  • Recovery: 8–12 weeks with limited activity

More on post-surgical rehab and timelines

Recovery and Rehabilitation

After surgery or conservative care, a structured recovery plan is essential. Here’s an example:

  • Weeks 1–4: Restricted movement, short leash walks, gentle stretching
  • Weeks 5–8: Begin physical therapy, increase controlled activity
  • Weeks 9–12+: Strengthening exercises, return to regular routines

Therapies like underwater treadmill sessions, cold laser therapy, and massage can all help your dog rebuild strength and reduce inflammation.

Be Prepared: The Risk of a Second ACL Tear

If your dog has suffered a torn ACL, it’s important to know that the risk of injuring the opposite knee is significantly increased. In fact, many dogs with one ACL tear will experience a rupture in the other leg—often within a year. This happens because dogs instinctively shift their weight to compensate for the injured limb, placing added strain on the “healthy” knee.

Proactive weight management, joint support supplements, and following a structured rehabilitation plan can help reduce that risk—but it’s essential to monitor for early signs of limping or stiffness in the other leg. Staying ahead of the issue can improve outcomes and help your dog maintain long-term mobility.

Preventing Future Injuries

Once your dog is healed, it’s time to focus on prevention:

  • Keep them at a healthy weight
  • Use ramps instead of stairs if needed
  • Avoid high-impact activities on slick surfaces
  • Maintain a regular, low-impact exercise routine (think walks, swimming)

We’re Here to Help

A torn ACL can feel overwhelming, but you’re not alone. At Animal Hospital Southwest, our team is here to guide you through the process—from diagnosis to recovery—with compassion, skill, and a deep love for animals.

If your dog is limping, slowing down, or just not themselves, let’s take a closer look together.

Book an appointment with us today—we’re here to help your pet get back on their feet.