Cruciate ligament rupture is the famous knee
injury of professional footballers. Dogs (rarely cats) can damage this
ligament too but the nature of this injury in dogs is very different to that of humans.
What are cruciate ligaments?
The
knee (stifle) is a complex joint comprised of the patella (kneecap), cartilage called the
menisci that cushions the knee, cartilage lining the joint and a
series of ligaments connecting the femur (thigh bone) to the tibia (shin bone).
Together, these components enable the joint to function properly. The knee has
two essential stabilising ligaments that cross over one another inside the knee
joint. They are called the cranial cruciate ligament and the caudal cruciate
ligament.
The cranial cruciate ligament is most commonly ruptured (torn).
Causes and signs of knee ligament damage;
1. Ageing of the ligament (degeneration); - Cranial cruciate ligament disease.
This is the most common cause in dogs. As the ligament weakens over time, the dog will slowly become lame as a result of the disease. They may be reluctant to get up, run or climb stairs and the limp may worsen after exercise and improve after rest. The knee is often swollen with varying degrees of pain, and muscle wastage can occur where the dog is not using the affected leg properly.
Factors that may contribute to degeneration and failure of the ligament include;
Obesity- excessive weight puts an extra strain on the knee joints.
Individual conformation - The shape/structure of a dog's legs.
Genetic factor - Some breeds of dog are particularly prone to cruciate injury (including Rottweilers, Labradors, Boxers, West Highland White Terriers, Newfoundlands).
2. Trauma;
Rupture of a healthy ligament (like in people) is rare in dogs.
This is usually as a result of a sudden twist of the hind leg or over-extension of the knee. This could occur if a dog suddenly changes direction whilst running for example.
Following trauma to the knee, a dog will have a sudden onset of lameness and usually hold the foot of the affected leg off the ground.
Diagnosis: The vet will carry out a thorough
examination of your dog, looking at how they walk, and manipulate the knee
joint to test for instability and looseness. In some cases, examination of the
joint is necessary under sedation to enable the detection of more subtle
instability of the knee as occurs with a partial tear of the ligament. Secondarily,
an x-ray will be taken to provide additional information - to see if there is fluid accumulation in the
joint, the degree of arthritis and to rule out other possible causes.
Surgery is
generally recommended for cruciate ligament rupture since it is the only way to
permanently control the instability in the stifle joint & to evaluate the
structures within the joint. There are different surgical options - stabilising the
knee using an artificial replacement ligament,
essentially mimicking the action of the original cruciate ligament, and techniques
that involve cutting and re-positioning the Tibia (shin bone) to alter the
mechanics of the knee joint to improve functionality. Referral to a specialist is
required for the latter. The best option for your pet depends on many factors
such as your pet’s activity level, size, age, conformation, and the degree of
knee instability. Sometimes small dogs can be managed satisfactorily with out
the need for surgery, depending on the severity of the injury. 
Recovery from cruciate surgery can take anything from 4-6
months and it is vital that you work closely with your vet and follow the
rehabilitation plan.
While prevention of injuries is difficult,
there are some factors that can decrease the likelihood of cruciate ligament
damage. First and foremost is avoiding obesity and secondly a good fitness
level of regular (but not excessive) exercise is advised. Please speak to your
vet or nurse!
In conclusion, cranial cruciate ligament
disease is a common condition affecting the knee joints of dogs. There is no
one perfect solution and unfortunately arthritis will gradually progress
whatever the treatment. However,
with carefully selected management, most patients can continue to enjoy a good
quality of life.
Disclaimer
The
contents of the Arden
House Animal
Hospital website are for
informational purposes only. The content is not intended to be a substitute for
professional veterinary advice, diagnosis, or treatment. Always seek the advice
of your Veterinary Surgeon with any questions you may have regarding your
animal’s medical condition. Never disregard professional medical advice or
delay in seeking it because of something you have read on this website.
Gorgeous Mimi was rushed into our Ruislip hospital after being hit by a car one Thursday morning. Vet Rachel examined her and found that she was in shock and in pain around her back end. She was admitted to the hospital, placed onto a drip and given pain relief.
