Torn Cruciates

Cruciate ligament damage in the knee joint is a reasonably frequent injury affecting athletes and footballers. What most people don’t know however is that this kind of injury can also happen in dogs (and rarely, cats) and is, in fact, a common cause of lameness in pets.

The proper functioning of a knee joint (or stifle, as it is called in animals) depends on 5 ligaments that hold the femur ( thigh bone) and tibia (shin bone) together at their bottom and top ends respectively. These ligaments have to be very strong indeed to cope with the stress loads they are routinely subjected to. Sometimes they just can’t take it, and then they tear or break.

The anterior cruciate ligament is the one that is damaged most often. It’s a sudden twisting, stopping action that does the damage – the sort of injury that can easily happen when a dog is rushing about, with the throttle wide open while it wheels about and changes direction. However we are now discovering that in dogs the most common cause of rupture of the anterior cruciate ligament is the end stage of “cruciate disease”, a degenerative condition of the joint that causes osteoarthritis. In these cases there is a low grade, chronic discomfort, followed by acute lameness when the ligament finally snaps like a frayed piece of rope.

Toy–sized dog breeds ( less than 10kg) and cats often make a rapid recovery over 6 weeks or so and often manage to cope well with simple restriction of exercise and pain relief in the immediate recovery phase. However larger dogs, especially if overweight, unfit, and giant breeds fare less favourably as secondary cartilage ( meniscus) damage and degenerative osteoarthritis can rapidly develop. This is often disastrous for the mobility of these poor animals – however we can help to minimize the effects.

Over the years there have been a huge number of types of procedures described for the repair of these ligaments, which implies that not one is perfect! However it is now generally agreed that 2 categories of surgery are of benefit.

In one type of operation the stifle is opened and inspected, and damaged ligament and cartilage removed. The joint is then stabilized with a special suture which wraps around the outside of the joint and stabilizes it.

A more advanced technique which is providing much benefit in very large or active dogs is a tibial plateau leveling osteotomy (TPLO). This operation is a tricky concept to come to terms with, but in essence the top end of the tibia ( shin bone ) is re-shaped by cutting it and fixing at a different angle with a plate and screws. This alters the angle at which the bones articulate in the joint and eliminates abnormal forces on the cruciate ligaments. It alters the biomechanics of the joint and makes that damaged ligament redundant!

We have been using this advanced technique at Western Suburbs Vet Clinic for 2 years now and we are really pleased with the advances in recovery we have seen. It is really satisfying to see some of our patients with one or both repaired knees charging around and fully active, instead of being crippled with arthritis. Of course some individuals do better than others, but we are convinced that this is now the best procedure on offer anywhere.

Total knee replacement surgery is still extremely specialist and only just past the experimental phase at present, but who knows what may be possible next!