Is Your Dog Limping? Signs of Cruciate Ligament Injury

Introduction

The cruciate ligaments are two ligaments located inside the knee joint that are crucial for stability. They are called “cruciate” ligaments because they cross each other in the form of an “X”. In dogs, two types of cruciate ligaments are present – the cranial cruciate ligament(CCL) and caudal cruciate ligament. The cranial cruciate ligament prevents excessive forward movement of the tibia and is most commonly injured in dogs.

Rupture or tear of the CCL is a very common orthopedic condition in dogs. Estimates indicate it affects up to 5-20% of dogs, with the incidence increasing significantly over the past few decades. It is especially common in larger breeds like Labradors and Rottweilers.

CCL injury causes rear limb lameness and instability in the knee joint. It is extremely painful and debilitating for dogs and also predisposes them to developing osteoarthritis over time. That’s why early recognition of the signs of CCL injury is crucial – it allows for timely veterinary management to treat pain, restore limb function and prevent long term joint damage.

Causes

The most common causes of cruciate ligament rupture in dogs are obesity, age, and genetics (VCA Animal Hospitals). Obesity puts additional stress on the joints and ligaments, making injury more likely. As dogs age, their ligaments naturally weaken and become more prone to injury. Certain breeds like Labrador Retrievers and Rottweilers are genetically predisposed to cruciate ligament issues.

an overweight dog with knee braces on

Other causes include traumatic injury from things like falling or playing roughly, as well as long-term wear and tear called degeneration. According to Colorado State University, while trauma is the most common cruciate ligament injury in humans, degeneration is more often the cause in dogs (CSU Veterinary Teaching Hospital).

Symptoms

The most common symptom of a cruciate ligament injury in dogs is lameness or difficulty bearing weight on the affected leg (PAWS, 2022). Dogs will often limp or avoid putting full pressure on the leg when walking. They may also show reluctance to walk or play. Other symptoms include:

  • Decreased range of motion in the affected leg
  • Swelling around the knee joint
  • Stiffness and pain, especially after exercise
  • Muscle atrophy over time
  • A “popping” noise that may indicate a torn meniscus

These symptoms can appear suddenly in the case of an acute injury, or gradually worsen over time with chronic ligament degeneration. Owners may notice the dog limping after a fall or vigorous activity. Symptoms often improve with rest but return with activity. Early intervention is key to prevent worsening of the injury.

Diagnosis

Diagnosing a cruciate ligament tear in dogs begins with a physical exam by the veterinarian. The vet will manipulate the dog’s knee joint and feel for instability, pain, and swelling. According to a study published in the National Center for Biotechnology Information, the drawer sign test, where the vet pulls forward on the tibia while feeling for laxity, is one of the most reliable indicators of a cruciate tear.

a vet performing a drawer test on a dog's hind leg

The veterinarian may also order X-rays to look for signs of arthritis and to rule out fractures or other injuries. However, X-rays cannot directly visualize ligament tears. For definitive diagnosis, the vet may recommend an MRI, which can clearly show the damaged cruciate ligament as well as any meniscus injuries.

Treatment

Treatment for cruciate ligament injury in dogs focuses first on rest and managing pain and inflammation. Strict rest and restriction of activity is recommended, along with the use of anti-inflammatory medications like carprofen or meloxicam to control pain and swelling (Colorado State University Veterinary Teaching Hospital). Cold compresses may also help reduce swelling and discomfort.

Unfortunately, most dogs will eventually require surgery to fully repair a torn or ruptured cruciate ligament (VCA Animal Hospitals). The most common surgical options are tibial plateau leveling osteotomy (TPLO), tibial tuberosity advancement (TTA), extracapsular stabilization, and lateral fabellar suture techniques. These procedures aim to stabilize the knee and prevent further damage to the joint.

After surgery, rehabilitation with controlled leash walking, swimming, and physiotherapy helps rebuild muscle strength and range of motion. With proper treatment, most dogs can return to normal function, though the prognosis is better the earlier the injury is addressed.

Surgical Options

There are several surgical options used to treat cruciate ligament tears in dogs. The three main procedures are:

Extracapsular Repair

In this procedure, the surgeon stabilizes the stifle joint by placing a strong nylon or other suture material around the fabella and through a hole drilled in the tibial crest. This tightens the joint capsule and supports the knee. According to VCA Hospitals, extracapsular repair has a 70-90% success rate in dogs under 30 lbs, but larger dogs have a higher failure rate with this technique[1].

Tibial Plateau Leveling Osteotomy (TPLO)

a dog's hind leg after tplo surgery

TPLO surgery changes the anatomy of the stifle joint to eliminate instability from cruciate disease. The tibial plateau angle is reduced by cutting and rotating the tibia. This causes stability in the knee joint throughout the gait cycle. According to the Whole Dog Journal, TPLO has a success rate over 90% and allows dogs to return to full function in 8-12 weeks[2].

Tibial Tuberosity Advancement (TTA)

In TTA surgery, the insertion point for the patellar tendon on the tibia is cut and moved forward. This alters the forces acting across the knee joint, eliminating instability. Southern Animal Health reports TTA has a success rate over 90% and most dogs can discontinue joint support after 8 weeks[3].

Recovery

Recovery after cruciate ligament surgery is a long process, requiring strict crate rest and gradual reintroduction of activity over 8-12 weeks. During this time, the knee needs to heal and scar tissue needs to develop to stabilize the joint.

Crate rest is critical and dogs should be confined for 4-6 weeks after surgery, only allowed out on a leash to go to the bathroom. Activity needs to be restricted to prevent re-injury. Physical therapy can begin after 2 weeks, focusing on range of motion exercises. Under the guidance of a vet, the dog can begin short 5-10 minute leash walks after 4 weeks. Stairs should be avoided for 6-8 weeks.

The recovery timeline is approximately:
– Weeks 1-2: Strict crate rest
– Weeks 2-4: Begin physical therapy

– Weeks 4-6: Short leash walks allowed
– Weeks 6-8: Increase activity gradually
– Weeks 8-12: Transition back to normal but avoid jumping/twisting

It’s important to follow up with the vet during the recovery process to ensure the knee is healing properly. With strict rest and rehabilitation, most dogs are able to return to full activity around 12 weeks after cruciate ligament surgery.

Sources:
https://www.licksleeve.com/blogs/news/dog-acl-surgery-recovery-week-by-week-timeline
https://sydneyanimalhospitals.com.au/post-operative-cruciate-ligament-care-for-dogs/

Prevention

There are several ways to help prevent cruciate ligament injuries in dogs:

Maintaining an ideal body weight can take pressure off the joints and ligaments. Overweight dogs are at higher risk for cruciate ligament tears. Keeping your dog at a healthy weight recommended by your veterinarian can help prevent injury.

Joint supplements containing glucosamine, chondroitin, and omega-3 fatty acids may also help strengthen connective tissue and prevent damage. Talk to your vet about supplement options for your dog.

Exercise that builds muscle, flexibility, and balance can strengthen joints and stabilize the knee. Activities like swimming or gentle agility work can be beneficial. Avoid intense activities like Frisbee that require a lot of jumping and quick turns. Always warm up and cool down before and after exercise.

Sources:
https://www.physio-vet.co.uk/blog/how-to-prevent-cruciate-ligament-injury-in-dogs/
https://www.licksleeve.com/blogs/news/how-to-prevent-acl-tears-in-dogs-six-things-you-must-do

Outlook

The outlook for dogs with a cruciate ligament injury depends greatly on whether they receive treatment or not. Without treatment, the prognosis is poor. The joint will remain unstable, leading to worsening arthritis, pain, and lameness over time. According to the Cummings School of Veterinary Medicine, dogs that don’t receive treatment will likely deteriorate within 6-12 months.[1]

With proper treatment, most dogs go on to live active, happy lives after recovering from a cruciate ligament injury. Surgery successfully stabilizes the joint in 85-90% of cases, allowing the dog to regain normal or near-normal function. With strict rest and rehabilitation post-surgery, inflammation and arthritis are reduced. With nonsurgical management, the prognosis is more guarded but dogs can still improve significantly. Close monitoring, lifestyle changes, weight management, medication, and physical therapy help keep the dog comfortable.

Potential complications following cruciate ligament surgery include infection, failure of the surgical implant, decreased range of motion, and progression of arthritis. With proper aftercare and follow-up, most dogs avoid complications and continue to improve over time. Monthly check-ups with a veterinarian are recommended for at least a year after surgery to ensure the dog is healing properly.

While the cruciate ligament cannot heal on its own once torn, dogs are able to adapt well and live happy lives despite this injury, especially when given proper treatment and management. With surgery, strict rest, medication, weight control, therapy, and regular vet visits, the prognosis for cruciate tears is good.

[1] https://vet.tufts.edu/wp-content/uploads/CruciateRupture.pdf

When to See a Vet

If your dog is showing any of the following signs, they require urgent veterinary care:

    a dog with a bandaged hind leg limping

  • Sudden severe lameness in one or both hind legs
  • Swelling around the knee joint
  • Reluctance to put weight on a hind leg
  • Instability in the knee joint or abnormal motion when manipulating the knee
  • Non-weight bearing lameness for more than 48 hours

These signs indicate a potential complete tear of the cranial cruciate ligament, which requires immediate veterinary assessment and likely surgical treatment. Delaying care risks further damage to the joint and cartilage. Even partial tears that cause intermittent lameness need prompt veterinary attention to determine the best course of treatment and rehabilitation.

Veterinarians will perform a thorough orthopedic exam, including evaluating joint laxity and pain response. They may recommend x-rays to assess the joint for damage. Treatment plans will be tailored based on exam findings and may include strict rest, anti-inflammatory medication, physical therapy, and/or corrective surgery for cruciate tears.

Cruciate ligament injuries are painful and debilitating. At the first sign of hind limb lameness, it’s important to schedule a veterinary visit for proper diagnosis and care. Early treatment greatly improves the prognosis and outcomes for dogs with this common knee injury.

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