Dog & Cat HospitalCalabasas

Patient Education

Cruciate Ligament (ACL) Tear

A torn cranial cruciate ligament (the dog equivalent of a human ACL) is the most common cause of hind-leg lameness in dogs — and one of the most treatable.

The cranial cruciate ligament (CCL) is a band of tissue inside the knee (stifle) that keeps the joint stable. When it stretches or tears, the knee becomes wobbly and painful, and the dog limps. In dogs, a CCL tear is usually the result of slow, ongoing degeneration rather than a single sports injury — which is why the other knee often follows within a year or two. The good news: it's one of the most successfully treated orthopedic problems in dogs, and our surgical team at Dog & Cat Hospital Calabasas repairs them routinely.

Signs & Symptoms

CCL injuries range from a sudden non-weight-bearing lameness to a subtle, intermittent limp that comes and goes for weeks. Watch for:

  • Limping or favoring a hind leg, often worse after rest or exercise
  • Sitting with one hind leg kicked out to the side
  • Difficulty rising, jumping, or using stairs
  • Swelling on the inside of the knee, or a clicking sound when walking
  • Stiffness that improves with movement, then worsens again
  • Reluctance to bear full weight on the leg

Many dogs tear the second ligament later, so a new limp on the opposite side warrants prompt evaluation.

Causes & Risk Factors

Most canine CCL tears stem from gradual ligament degeneration, so a normal jump or turn finally completes a tear that was years in the making. Contributing factors include:

  • Breed and genetics (Labradors, Rottweilers, Newfoundlands, and many large breeds are predisposed)
  • Excess body weight, which multiplies the load on the joint
  • Poor physical conditioning paired with bursts of intense activity
  • Conformation — the shape and slope of the tibia in some dogs
  • Age and prior partial tears that weaken the ligament over time

Is your dog limping on a hind leg?

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How We Diagnose It

Diagnosis starts with a hands-on orthopedic exam. The hallmark is a "cranial drawer" or "tibial thrust" — abnormal forward movement of the shin bone when the knee is manipulated. Because tense or anxious dogs can guard the joint, we often confirm the findings under sedation. Digital radiographs (X-rays) let us assess joint swelling, rule out other problems, and plan surgery. In partial or subtle tears, sedated examination and imaging together give the clearest answer.

Treatment Options

Surgery is the most reliable way to return a dog to comfortable, stable function, and the right procedure depends on the dog's size, activity level, and the shape of the knee. Common approaches include:

  • TPLO (Tibial Plateau Leveling Osteotomy) — re-angles the top of the tibia so the knee is stable without the ligament; preferred for active and larger dogs
  • Lateral fabellar suture — a nylon implant that mimics the ligament while scar tissue stabilizes the joint; often chosen for smaller dogs

Weight management, controlled activity, joint supplements, and pain control support recovery and protect the other knee. Conservative (non-surgical) management may be considered for very small or high-anesthetic-risk patients, though most dogs do best with surgery.

When to See Our Team in Calabasas

If your dog is limping on a hind leg — even intermittently — have it evaluated before the joint develops further arthritis. Early diagnosis means more treatment options and a smoother recovery. Our surgical team in Calabasas can examine the knee, confirm the diagnosis, and walk you through the best repair for your dog. Book an appointment or call us to get started.

Frequently Asked Questions

1Can a torn CCL heal without surgery?
A fully torn cranial cruciate ligament does not heal back together on its own. Some very small or high-risk dogs are managed conservatively with weight control, activity restriction, and pain management, but most dogs — especially active or larger ones — return to comfortable function fastest and most reliably with surgery.
2How long is recovery after CCL surgery?
Most dogs bear weight within days and complete a structured recovery over about 8 to 12 weeks, with strictly controlled activity at first and a gradual return to normal exercise. Your surgeon will provide a week-by-week plan.
3Will my dog tear the other knee too?
It's common. Because canine CCL tears usually come from ligament degeneration rather than a one-time injury, a significant share of dogs tear the opposite ligament within a year or two. Keeping your dog lean and fit lowers that risk.
4Is my dog too old for surgery?
Age alone isn't a barrier. We assess overall health with a physical exam and bloodwork; many senior dogs do very well with modern anesthesia and monitoring. We'll give you an honest assessment for your individual pet.
5How do I know if it's the CCL and not something else?
Hind-leg lameness can also come from hip, foot, or back problems. An orthopedic exam — sometimes under sedation — plus X-rays lets us pinpoint the knee and rule out other causes before recommending treatment.
6What happens if I don't treat my dog's torn ACL?
Left untreated, the unstable knee develops progressive arthritis, the dog stays painful, and the cartilage cushion (meniscus) is more likely to tear too. Dogs also tend to overload the other leg, raising the odds of tearing that ligament. Early treatment leads to better long-term comfort.
7Can my dog still walk with a torn cruciate ligament?
Many dogs will toe-touch or limp on the leg, but they're painful and the joint is unstable. Walking on it without treatment accelerates arthritis and meniscal damage, so it's not a substitute for evaluation and a treatment plan.
8How much does cruciate (ACL) surgery cost for a dog?
Cost depends on the dog's size, the technique chosen (TPLO vs. lateral suture), and whether the meniscus needs treatment. We give a written estimate at the surgical consultation so there are no surprises.

Related

ProceduresTibial Plateau Leveling Osteotomy (TPLO)ProceduresACL Repair (Lateral Fabellar Suture)

Is your dog limping on a hind leg?

Our surgical team can diagnose a cruciate tear and recommend the right repair. Early evaluation protects the joint and speeds recovery.

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