Cranial Cruciate Ligament Tears in Dogs

Helping your dog get back to a happy, pain-free life.

Cranial cruciate ligament (CrCL) tears are one of the most common causes of back-leg lameness in dogs. If your dog is limping, reluctant to jump, or suddenly won’t use one of their back legs, a CrCL injury may be the reason. This page explains what a CrCL tear is, how we diagnose it, and the treatment options available, so you know what to expect and how we can help.

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What Is the Cranial Cruciate Ligament?

The cranial cruciate ligament is a strong band of tissue inside the knee (stifle) joint.
Its main jobs are to:

• Prevent the shin bone (tibia) from sliding forward under the thigh bone (femur)
•  Help stabilise the knee during walking, running, and turning
•  Protect other structures in the joint, including the meniscus (the “shock absorber” cartilage)

In humans, a similar ligament is called the anterior cruciate ligament (ACL), which is why you may sometimes hear people call this an “ACL tear” in dogs.

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Why Do Dogs Tear Their CrCL?

In many dogs, the ligament doesn’t suddenly snap during a single accident. Instead, it weakens gradually over time due to a combination of:

• Breed and genetics (some breeds are more prone – e.g., Labradors, Rottweilers, Boxers, spaniels)
• Body weight (overweight dogs put more strain on their joints)
• Conformation and tibial plateau angle (the shape and angle of the bones in the knee)
• Age-related changes in the ligament itself

Because the ligament is slowly degenerating, it can then tear partially or completely during normal activities – such as running in the garden, jumping out of the car, or even just slipping on the floor.

Important point for owners:
It’s usually not your fault and not simply due to one wrong move. It’s more like a rope that frays over time and eventually breaks.

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Common Signs of a CrCL Tear
Dogs with a cranial cruciate ligament tear may show:

• Sudden lameness in one back leg
• Toe-touching or non-weight-bearing on the affected leg
• Difficulty rising, jumping into the car, or climbing stairs
• Stiffness, especially after rest
• Sitting with the leg held out to the side
• Muscle loss on the affected thigh if the problem has been present for a while
• Swelling around the knee joint

Sometimes the lameness improves with rest and pain relief, only to return. This is typical of partial tears that worsen over time.

If both knees are affected (which can happen), your dog may appear generally weak in the hind end rather than obviously lame on just one side.

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How We Diagnose CrCL Tears

At your dog’s appointment, we will:

1. Take a detailed history
   • When did the lameness start?
   • Was there a specific incident, or did it come on gradually?
   • Does it worsen after exercise or rest?
2. Perform a full orthopedic exam
   • We carefully feel and move each joint.
   • Special tests, such as the cranial drawer test and tibial thrust test, help us check for abnormal movement in the knee.
     
3. Use imaging where needed
   • X-rays (radiographs) can’t show the ligament itself, but they do show bone alignment, joint swelling, and arthritic changes.
   • In some complex cases, further imaging (such as ultrasound, CT, or MRI, or arthroscopy) may be recommended.

In many dogs, a CrCL tear can be strongly suspected from history + physical exam, then confirmed with X-rays and, in some cases, during surgery.

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Why Treatment Matters

A torn cranial cruciate ligament causes:

• Pain and lameness
• Instability in the knee, allowing the tibia to slide forward
• Damage to the meniscus, the shock-absorber cartilage inside the joint
• Osteoarthritis (arthritis) that worsens over time

Without appropriate treatment, most dogs will:

• Continue to limp or be intermittently lame
• Develop progressive arthritis, leading to more pain and stiffness
• Have a reduced quality of life and may struggle with normal activities they enjoy

Early and appropriate treatment helps:

• Reduce pain
• Stabilise the joint
• Protect the meniscus
• Slow down arthritis development
• Restore as much normal function as possible

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Treatment Options

We tailor treatment to each dog, considering size, age, activity level, other health issues, and budget.

1. Surgical Treatment

For most medium and large dogs, surgery is recommended because it provides the best chance of long-term comfort and function.

Common surgical options include:
Tibial Plateau Leveling Osteotomy (TPLO)

• The top of the tibia (shin bone) is cut, rotated, and stabilised with a plate and screws.
• This changes the shape of the knee so that it no longer relies on the CrCL to be stable.
• Benefits: excellent stability, especially for active or larger dogs; high success rates for return to good function.
• Typical candidates: medium–large, athletic, or working dogs, and many smaller dogs as well.

Other Techniques (e.g., Lateral Suture / Extracapsular Repair, TTA, etc.)

• A lateral suture uses a strong synthetic material placed around the outside of the joint to mimic the ligament’s function.
• Other osteotomy procedures (like TTA) also change the biomechanics of the joint.

We will discuss which surgery is most appropriate for your dog, taking into account their size, lifestyle, and your goals.

       2.  Conservative (Non-Surgical) Management

In some cases – for example, very small dogs, dogs with serious health issues, or owners who are unable to pursue surgery – we may discuss conservative management, which can include:

• Strict activity restriction (controlled lead walks only)
• Weight management (getting to or keeping an ideal body condition is critical)
• Pain relief and anti-inflammatory medication
• Joint supplements (e.g. omega-3s, glucosamine/chondroitin)
• Physiotherapy/rehabilitation exercises

Conservative management may improve comfort, but the knee is usually less stable compared with surgical options, and arthritis often progresses more quickly.

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What to Expect with Surgery

Before Surgery

• Pre-anesthetic blood tests will be completed along with an ECG of their heart.
• Your dog will be admitted to the hospital and receive pain relief and sedation before surgery.

During Surgery

• The procedure is performed under general anesthesia.
• The joint is inspected; any damaged meniscus is treated; and the chosen stabilization procedure is carried out.
• X-rays are repeated after the operation to check implant positioning.

After Surgery (Hospital Stay)

• Most dogs stay in the hospital for 1 day while their epidural pain relief wears off. 
• We monitor pain levels closely and adjust medications as needed.
• You’ll receive detailed discharge instructions on rest, bandage care (if present), and medications.

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Recovery & Rehabilitation

Healing and recovery are a team effort between you and the veterinary team.

First 2 Weeks (Early Healing)

• Strict rest: no running, jumping, stairs, or off-lead activity.
• Short, controlled lead walks only (usually just for toileting).
• Keep the surgical site clean and dry; prevent licking or chewing (use a protective collar if needed).
• Give all prescribed medications as directed.

Weeks 3–6 (Gradual Increase)

• Lead walks can slowly lengthen, if advised.
• Gentle physiotherapy exercises may be introduced.
• We may schedule a re-check and X-rays to assess bone healing.

Weeks 6–12 and Beyond (Return to Activity)

• If healing is progressing well, exercise is gradually increased.
• Many dogs return to a very good level of activity, including off-lead walks and play.
• High-impact activities (e.g., ball-chasing, agility) are usually reintroduced slowly and only after the vet confirms it is safe.

Every dog heals at a different pace. We will provide a personalized rehab plan and review your dog regularly.

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Long-Term Outlook (Prognosis)

With appropriate treatment and good home care:

• Around 85–90% of dogs experience a significant improvement in comfort and function after surgery.
• Mild to moderate arthritis is still expected long-term, but most dogs can enjoy an active, happy life.
• 50% of dogs that tear the CrCL in one knee will eventually injure the ligament in the other knee at some point in the future, due to the underlying degenerative process.

Keeping your dog slim, fit, and well-exercised (once healed) is one of the best ways to protect their joints.

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How You Can Help Your Dog

Owners play a vital role in success:

• Follow rest and activity instructions closely
• Give medications exactly as prescribed
• Attend all re-check appointments and X-ray visits
• Maintain a healthy weight – ask us if you need a weight-loss plan
• Consider joint supplements and, where appropriate, physiotherapy/hydrotherapy

If at any point you notice:

• Sudden worsening of lameness
• Swelling, redness, discharge, or your dog chewing at the wound
• Reluctance to use the leg after previously improving

Please contact us straight away.

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