Cruciate Ligament Injuries - a question and answer session.

The rupture of the cruciate ligament in the stifle (equivalent to our knee joint) is one of the most common orthopaedic problems needing surgery in dogs. It causes a lot of anxiety in many dog owners who naturally have many questions about it. In this blog, we’re going to look at some of these. The answers have been accumulated by Paul over the 30 years (and a bit more!) in which he has been helping these patients and their owners.

First, what is a cruciate ligament? 

The cruciate ligaments are the fibrous strands that cross over in the middle of the stifle or knee joint in both dogs and humans. The most easily injured is the “cranial cruciate” (the one in front), which is important in maintaining stability of the joint and preventing the bones sliding over one another. If this ligament is torn, abnormal movement in the joint results, leading to lameness or at worst a tendency to fall over with the leg giving way. Some dogs may even respond by holding the leg right off the ground, being unable to use it.

Do affected dogs always need surgery or can they just have hydrotherapy or other non-surgical treatment?

Sometimes, particularly in small dogs less than 10kg bodyweight, they can do quite well without surgery - although the torn ends of the ligament never reconnect. In bigger dogs, however, the instability is usually too severe for them to be able to regain normal use of the leg without surgery. Some owners want to rush into surgery, whereas some prefer to wait and see if their dog recovers before making that decision.

If a dog doesn’t respond to non-surgical approaches, what are the options for surgery?

There are a range of different operations available for dogs with cruciate injuries.

The least invasive option is a lateral suture where a synthetic thread (or “suture”) is placed around the outside of the joint, usually through the front of the tibia (shin-bone), to provide some stabilisation. Recovery can be very quick because this is minimally invasive, but it tends to fail in big dogs. Having said that I have had success in dogs as big as a Rottweiller but the failure rate is quite high.

Then there graft replacement surgery which I personally favour. This operation  offers the solution whereby a graft of the dog’s own skin replaces the old ligament where it has torn. This means that each of the hind legs are biomechanically symmetrical - in other words, the forces are balanced and even, minimising the risk of further injury. This technique dates back to Paatsama in 1952.

Then there are the bone sawing techniques of various types which have had various modifications over the past 20 years since they were introduced starting with the TPLO in 1994.

Why do the human surgeons use a graft replacement technique unlike most vets?

The evaluation of the clinical outcomes from each type of operation are constantly debated and there are many variations in the studies published including length of study over months, years, or decades. Many of the newest surgical techniques being tried have no long term studies to evaluate them because they have not been done for long. One question that is important is that if a particular technique was thought to be ‘excellent’ or ’very good’, why is there a new technique being invented every 2-3 years?

Most other vets prefer to use techniques which seem to have a faster rate of recovery in the short term - however, how effective they will be in the long term is more debatable. For many dog owners the speed of recovery is less important than the duration in years afterwards in which their dog can enjoy an active life, and it is the evaluation over those long years that matters most to the caring owner. So, like the human surgeons - who want their repairs to last a (human) lifetime! - I prefer to use a tissue graft because I believe it gives a longer-lasting repair. After all, why would a dog owner want their dog to have the bone sawn if the replacement of the torn ligament with a new one has been shown to give good results over many years?

More information is available in the cruciate section of this website, or you are welcome to contact us with any other questions you might have!