Cruciate Ligament Rupture

Cruciate Ligament Rupture

PDF version

What happens when the cranial (anterior) cruciate ligament ruptures?
The cruciate ligament is one of two tough pieces of fibrous tissue that joins the femur (thigh bone) to the tibia (shin bone).  If it ruptures you will notice a sudden onset complete hind limb lameness after exercise. The exercise that causes the problem usually invoves speed and changes in direction. Like ball throwing. In older animals the onset may be more gradual and there will be a persistent lameness in one of the hind legs that doesn’t improve with time.

What dogs are affected by cruciate rupture?
Large breeds are more susceptible than small. Dogs with certain types of stifle conformation appear to be more prone such as Rottweilers, Newfoundlands, Mastiffs, Staffordshire Bull Terriers and Labrador Retrievers with Bassets, Old English Sheepdogs and Greyhounds to a lesser degree. Spayed, overweight female dogs are also over represented. Obesity is a clear risk factor.

What does cruciate rupture mean to your dog & you?
The condition is painful and will ultimately mean that your dog will suffer from some degree of osteoarthritis in that joint regardless of what course of action you take.
Whether you opt for surgery or not it will mean that your dog will need to be properly rested and fitness built up over about a three month period.
The ligament will never repair in it’s orginal form but through various methods the joint can be stabilised enough to mimic the restraining force that the ligament usually exerts.
Large and giant-breed dogs are more likely to get cruciate later in life if they are overfed and gain weight quickly as puppies. If you have such a puppy, you may be able to reduce the chance of future hip dysplasia by careful feeding.

How is cruciate rupture diagnosed?
Your veterinarian will probably suspect cruciate disease if your dog has pain, lameness or swelling in the knee. Your vet will take x-rays to evaluate the general fit of the femur and pelvis, and to look for any osteoarthritic changes in the knee joint. Your vet will be able to judge the degree of laxity of the joint by manipulating the femur and tibia in a specific way on each other. This can be performed conscious or if your dog is resisting it can be performed whilst under sedation.

How is cruciate rupture treated?

Surgical correction is the treatment of choice especially in animals over 10kgs. Lighter animals can sometimes heal over a period of three months to a point where the resulting scar tissue is enough to stabilise the joints but the joint will suffer from more degenerative changes as a result.

There are various surgical methods available and their success generally depends on the skill of the surgeon. In general practice your vet will most often use the lateral fabellar suture technique whereby a false ligament is placed on the outside of the joint to mimic the restraining force of the actual ligament without impinging on the joint itself.





Specialists generally use the TPLO (Tibial Plateau Levelling Osteotomy) or TTA (Tibial Tuberosity Advancement) whereby they try and recreate the angle of the top of the tibia to prevent the femur from sliding forward.




Various therapies would be indicated as preventative measures, post operatively or if you decided to go the conservative route.


An appropriate diet in the growing phase of a dog’s life will go a long way towards preventing a problem or at least minimising it. That means keeping the energy and mineral balance correct and not over feeding. Feed the best quality breed size specific diet you can afford.

Overweight dogs suffer from osteoarthritic pain far more than slimmer dogs so if your dog is overweight it would help immensely to put him on a calorie controlled diet.
There are specifically formulated joint diets containing natural anti-inflammatory supplements that can alleviate pain.

Nutraceuticals such as glucosamine and chondroitin are also be helpful. These substances help to lubricate the joint and may replace lost nutrients in the damaged cartilage layer.
Omega 3/6 Oils help to alter the composition of the fatty layer surrounding the cells making it more likely to breakdown into non inflammatory rather than inflammatory products.
Various other supplements have been used to mixed effect.

Controlling exercise is important in managing the pain. Obviously it is best to rest the dog if the pain is acute but if you need to exercise then short, frequent ,lead walks are better than long. Swimming is an excellent form of non-weight bearing activity. Avoid any vigorous game that involves jumping and changing direction quickly like ball throwing or agility exercises.

Adjunctive therapies
Physiotherapy, massage, acupuncture and hydrotherapy are also highly recommended as adjunctive therapies to strengthen and relax the muscles.

If surgical or conservative therapy doesn’t work your vet may resort to anti-inflammatory drugs.