Tip of the Month

3/26/2012 Knee Injury in Dogs: Ruptured Anterior Cruciate Ligament (ACL)

One of the most common orthopedic problems in dogs is a torn anterior cruciate ligament. If you are a sports fan, you are very familiar with this injury, especially since it puts the playerís career on hold. A torn anterior cruciate ligament (or ACL) is a tear of the ligament (tissue holding two bones together ), located in the knee.

The dog will limp usually although sometimes the limp going away for a while despite the presence of the tear. The inside of the knee can swell up. The veterinarianís exam will include a physical examination and x-rays to confirm the diagnosis. During the exam the vet holds the femur in place and if the ligament is torn, the tibia will usually slide forward when manipulated. While examining the x-ray, the veterinarian is looking for fluid retention, possible bone fragments and the degree of arthritis that has set in.

In dogs, ACL is caused by a variety of possible factors. One of these factors is heredity. Certain breeds have had higher occurrences of torn ACLís then others. Also, obesity will put more stress on the knee and potentially lead to knee degeneration. Or it can be a simple mis-step that finishes off the already affected but not yet torn ligament.

In small dogs, under 30 lbs, the veterinarian may opt to restrict the dog`s activity and prescribe anti-inflammatory medication. With the proper care the ligament will start healing and the condition may improve between 6 weeks to 2 months. Keep in mind that a lack of a healthy ACL may cause bone spurs, pain, arthritis and decreased range of motion.

In the case of large dogs, surgical repair is required, as the ligament is not able to heal on itís own due to excessive size and body pressure. There are multiple surgical techniques, all of them with the intention of stabilizing and reconstructing the joint. They can consist of using synthetic sutures to re-create the ligament or cutting and repositioning the bone with plates and screws. Post-operation, the dog will not be bearing weight for about 3 weeks. With proper care, they should be able to start using the leg fully in 2 to 3 months.

Keep in mind that when one leg is affected, the other leg will carry much more weight then normal. This added strain on the unaffected leg can often lead to a tear of the ligament in the opposite knee.

When the dog is discharged from the hospital after the surgery, the veterinary assistant will make sure that the owner is thoroughly informed of the proper care. One of the things you can do at home, to help the healing, is ice the knee in order to reduce swelling. The veterinary assistant can demonstrate passive range of motion which is a great physical therapy. The emphasis needs to be placed on restricted activity, for surgical and non-surgical cases. This includes keeping the patient confined in a crate at all times during recuperation, except for leashed short walks only for the animal to void their bladder and defecate. Especially with large dogs, assistance while getting up may be needed. For giant breeds you may need to use the sling up to 4 weeks, while small breeds may not need any assistance at all. If the dog is overweight, a diet needs to be implemented. Hydrotherapy is also a great low impact exercise, but it is up to the veterinarianís discretion to include it as a part of the treatment plan.

In short, if you notice your dog being lame on a hind leg, take them to the veterinarian as soon as possible, not only to treat the problem, but also to prevent any possible complications. Unaddressed injury can cause permanent lameness and pain.

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