What is the anterior cruciate ligament and what does it do?
There are two cruciate ligaments in each knee (in dogs as in humans), the anterior and posterior cruciate ligaments. They are tough fibrous bands that keep the knee joint stable, strong and moving properly. The one that most commonly breaks or stretches is the anterior cruciate ligament.
How did my dog damage a cruciate ligament?
The damage most likely occurred by jumping and landing badly. It is a common injury in the knees of footballers for this reason. Occasionally, the injury can occur by “overextension” of the knee, for example by the hind leg stepping down into a hole while your dog is running. Either way it causes partial or complete tearing, or sometimes just stretching, of the cruciate ligament.
Why is my dog limping?
When the cruciate ligament is torn or stretched, it causes the joint surfaces inside the knee to rub against each other instead of “rolling” along each other. The rubbing causes pain when putting weight on the injured leg and your dog limps in response.
Are some dogs more likely to have this kind of injury?
Probably the biggest risk factor is excess weight as this puts these ligaments under greater strain, especially in very active dogs. Dogs that do a lot of jumping, for example catching balls, are also more prone to injury.
There is also a lot of evidence to suggest that a previous, sometimes minor, injury of the knee can cause a degenerative change which weakens the cruciate ligaments in that knee.
What do we do now?
The vets at Mont Albert Vet can do surgery to restore the stability of the knee joint. This is commonly called a knee reconstruction or cruciate repair.
The alternative is to do nothing and allow your dog's knee joint to strengthen up with strict rest over a long period. Unfortunately this is likely to lead to severe degenerative joint disease (DJD) in the knee joint. DJD is a type of arthritis that can lead to pain and limping in the long term. The other concern with just rest is that improvement is much slower than with surgery.
What are the pros and cons of surgery?
Surgery quickly restores the strength and stability of the knee joint. This returns comfort more quickly and reduces the amount of long-term damage to the injured joint. The downsides of surgery are concerns you might have about the anaesthetic, the risks of post-operative complications such as infection, and the cost. Please feel free to discuss these with us.
When should surgery be done?
Surgery is best done soon after the injury occurs. If surgery is not done within 3 to 4 weeks of the time of injury, it's likely there will be a lot more permanent damage to the knee joint (DJD).
What is actually done during the surgery?
The vets at Mont Albert Vet open the knee joint from the side and inspect damage to the ligaments and the menisci (commonly called cartilages). Any damaged tissues that are no longer working properly are removed gently and an artificial ligament is put in. This artificial ligament is usually made of a type of plastic such as polypropylene or nylon. The incision is closed and your dog can go home the same day.
Sometimes we will refer you and your dog to a specialist surgeon for a different type of surgery which changes the shape of the top of the tibia. This type of surgery may give better results in large-breed dogs than conventional surgery can.
What needs to be done after surgery?
Antibiotic tablets must be given to your dog for the first five days. Sometimes a course of a medication called Cartrophen is recommended to reduce the development of arthritis.
For the first 2 weeks there should be no exercise and no running, jumping or climbing (stairs, steep inclines, etc). Your dog should be kept confined to a small area, preferably indoors. Some dogs need to be confined to a pen or enclosure. Pens or enclosures can be hired so please ask us for details if you need one.
During weeks 3 and 4, there should still be no running, jumping or climbing. Your dog should be taken for a 10-15 minute walk on a lead twice a day.
During weeks 5 and 6, still no running, jumping or climbing but walks can be increased gradually to 30 minutes twice a day on a lead.
It is important to remember that the operated leg may never be quite as good as new but following the above recommendations should give your dog the best possible result.