Injuries to the cranial cruciate ligament are very common in dogs with some breeds being particularly susceptible. Some of the over-represented breeds include rottweilers, german shepherd dogs, labradors and west highland white terriers.
The cranial cruciate ligament is found in the knee and prevents the tibia (shin bone) from sliding forward in relation to the femur (thigh bone) whilst weight bearing. It is a very strong ligament that can be damaged for many reasons. (Click on the image on the left to enlarge the picture).
People usually tear the ligament when they catch their leg in extension during exercise. You will commonly hear of footballers and skiers damaging the cranial cruciate ligament. In humans, repair is usually performed with a technique to replace the damaged ligament.
In animals, there is no perfect way to repair a damaged cruciate ligament. There are MANY different techniques used by veterinary surgeons to treat animals with cranial cruciate ligament injuries but none are perfect. It is widely accepted that the best techniques have a success rate of around 90%.
In dogs, injuries may occur following a traumatic incident such as a road traffic accident in a similar manner to human injuries. However, it is now believed that the majority of cranial cruciate ligament injuries occur due to a degenerative process occuring within the knee joint resulting in a gradual weakening of the ligament. Some animals may demonstrate a hind leg lameness just due to the swelling occuring within the joint. Other animals may appear to rupture the ligament acutely after e.g. running on an uneven surface and catching the leg in extension. In these cases it is thought that the injury caused running may be the "Final straw" to a weakened ligament and the ligament may actually fail due to a chronic process.
Some animals, particularly smaller ones, may cope with conservative management. This usually consists of a 6 week period of rest (and possibly pain-killers) followed by a gradual increase in exercise, Hydrotherapy (swimming) is a useful way to build up the lost muscles in the injured leg.
Unfortunately most animals will require some form of surgery to stabilise the stifle joint.
Some methods (mostly the older ones) aim to replace the damaged ligament. This can be done using strips of tissue (e.g. fascia or sometimes skin) placed within the joint to act as ligaments or by placing man-made materials within the joint to act as ligaments.
A more commonly used method to stabilise a knee joint is to place a suture outside the joint. This suture is usually made of nylon but metal wire is sometimes used.
Modern methods to stabilise a stifle following a cranial cruciate ligament injury include the tibial plateau leveling osteotomy (TPLO) and the tibial tuberosity advancement (TTA) technique. These methods aim to change the dynamics of the stifle joint to remove the need for having a cranial cruciate ligament. They are currently recommended by most specialist orthopaedic surgeons as the treatment of choice for cranial cruciate ligament injuries, especially in large breed dogs.
Milton Keynes Veterinary Group recommends the TPLO procedure for most dogs requiring cruciate surgery. CLICK HERE for more information regarding the TPLO procedure (graphic images of the surgical technique are shown).
