Cruciate Ligament Rupture

Rupture of the cruciate ligament may occur suddenly or gradually and this can be reflected in the appearance of the signs of the condition which include lameness and stiffness of the knee. Full rupture of the cruciate ligament causes instability of the knee and this may lead to joint swelling and wasting (atrophy) of the muscles of the hind limb.

Rupture or tear can be caused by trauma or age related changes, although the size and conformation of some dogs makes them more likely to suffer from this condition.

Symptoms and Diagnosis

The initial symptom is often acute lameness with the affected leg, the dog may use the leg walking but will stand with the toes just touching the ground. Dogs with cruciate ligament rupture often prefer to sit with the affected limb straightened out in front of them rather than tucked up; this is because they do not like to flex the knee. Clicking noises may be heard and swelling may be present. The process of osteoarthritis will have begun and will tend to progress with time.

Diagnosis is by veterinary examination and x-ray.


If causing persistent problems, and especially in larger dogs, the condition is best treated with surgery to stabilise the knee. There are many different surgical techniques for treating the condition. Some of the common surgical techniques used to treat the condition include:

  • Intracapsular Technique - Replacing the ligament with a graft
  • Extracapsular Technique - Restoring stability using sutures
  • Periarticular Technique - Tibial Plateau Leveling Osteotomy (TPLO) restoring the stability by altering the anatomy of the stifle.

In the long run, all joints with cruciate ligament rupture will develop some degree of osteoarthritis. However, for most dogs the response to surgery is good and the osteoarthritis does not seem to cause problems for several years.

An appropriate period of convalescence and rehabilitation will follow surgery, ideally including Hydrotherapy and Physiotherapy and Medication for pain relief.