Cruciate Ligament Injury is the term used to describe any sprain, partial tear or more commonly, complete rupture (where the ligament is completely torn) of the Cruciate Ligament, inside the dog (or cat) knee.
Cruciate Ligament Injury is an important cause of lameness in the dog, and can lead to permanent severe lameness, or even debilitating arthritis, if not managed or treated correctly.
What is the Cruciate Ligament, and why is it so important?
The knee joint (or stifle as it is known in animals) is principally a hinge joint between the femur (thigh bone) and the tibia (shin bone). The knee joint is held together by a number of strong ligaments, including the collaterals and the cruciates.
The medial and lateral collaterals prevent the knee from hinging from side to side, and the cruciate ligaments prevent the tibia sliding backward and forward with respect to the femur.
If the ligament is broken the tibia slides forward when the animal bears weight. This sliding movement causes pain and inflammation in the joint. The pain obviously will cause lameness and persistent inflammation can be associated with progression of arthritis in the joint, which can lead to permanent lameness.
Typical signs of lameness associated with Cruciate Injury
Lameness associated with cruciate injury can be sudden in onset (for instance if your dog tears the cruciate at exercise), but can also be slower in onset if gradual deterioration and breakdown of the ligament occurs.
In fact what commonly happens is a mixture of both of the above, whereby you observe a gradual onset low-grade lameness, followed by a sudden onset more severe lameness when the ligament breaks.
Typically during the early low-level lameness your dog will only be stiff when getting out of bed, or after lying down. Lameness eases up during exercise and very often lameness is forgotten altogether if the dog is distracted (i.e. chasing a squirrel). The stiffness after rest will often be worse following a period of increased exercise.
In long standing cases of cruciate injury you may notice loss of thigh muscle in the affected limb. Animals with cruciate injury will often “unweight” the injured leg, by standing with more weight on the good leg. You may notice the sore leg positioned slightly to the side of the body, with the paw not placed fully on the ground.
It is important to realise that these are typical signs associated with cruciate injury. Individual cases may present quite differently, and other causes of hind-limb lameness (i.e. hip injury or hip arthritis) can present in a very similar manner.
How do we treat Cruciate Injury?
How we choose to treat cruciate injury will depend on several factors including the degree of damage to the ligament, the size and weight of your dog, and the type of lifestyle/activity etc.
Low-grade Injury i.e. simple sprain
In the same way we might treat a sprained ankle in ourselves, simple ligament sprain can often be treated by a short period of rest and the use of anti inflammatories.
Rest can vary between total restriction of all activity (ie cage confinement and lead walking only in the garden for toilet purposes), or can simply mean moderation of exercise (i.e. “house arrest” and only 10-15 minutes lead walking per day).
If lameness resolves then gradual return to exercise is advised. Gradual build-up of exercise is extremely important. Too rapid a return to too much exercise can result in recurrence or even worsening of ligament injury.
Severe Injury/Complete Ligament Rupture
Treatment of more significant cruciate injury can be confusing. There is a large range of different surgical techniques, management options, and even more different opinions as to how these should be implemented.
The majority opinion divides the available options into three broad categories based on weight of the dog.
Rehabilitation following Cruciate Injury?
Rehabilitation following cruciate injury and/or following surgical repair involves a carefully controlled program of restricted activity followed by gradually increased exercise, physiotherapy, and can include other physiotherapy type activities including hydrotherapy.
Each animal is unique and, in practice, each animal requires a bespoke rehabilitation program. We give specific advice based on your dog’s requirements.