Injury of cranial cruciate ligament is a relatively common injury of the stifle (knee) of the hind limb of the dog. It can be a debilitating injury causing significant lameness.

What is the CCL?
The CCL is major stabiliser of the stifle (knee). It plays a very important role in providing stability to the joint, by preventing excessive hyperextension (straightening), internal rotation (twisting) and tibial shear force. Shear force results from loads transmitted through the stifle when weight is placed on the leg. If the shear force were unopposed this would cause the tibia to move forwards in relation to the femur (instability).

What is the consequence of CCL injury?
When the CCL fails, these movements are no longer restricted. This causes instability in the stifle, abnormal movement and overloading the structures within the joint and causing pain. The cartilage meniscus is one such structure that is frequently damaged when the CCL fails. The mensici are shock absorbing structures within the stifle.

Unfortunately CCL injury is likely to lead to relatively prompt degenerative change (osteoarthritis) within the joint. In the early stages of disease the stifle tends to be painful because of the instability and consequences of this. Progressive osteoarthritis can become important in later years.

CCL injury causes joint instability, lameness, pain, and progression of osteoarthritis.

How is the CCL injured?
CCL failure can result from sudden injury or gradual degeneration of the ligament. Sudden injury is most commonly associated with hyperextension or internal rotation of the leg, that may occur when a dog’s foot may be caught in a hole or fence. Jumping can also cause CCL rupture if forces exceed the breaking strength of the ligament.

CCL failure can more commonly occur because of degeneration. This can occur with ageing (especially in large-breed dogs), conformational abnormalities (straight rear limbs) or inflammation within the joint. With ligament degeneration , even repetitive normal activities can cause rupture of the ligament. It is these cases that we see mostly commonly at our practice.

Dogs that are overweight appear more at risk of CCL injury.

Often in the dog, ligaments weakened by degeneration are more susceptible to trauma.

How does injury of CCL effect my dog?
CCL injury causes joint instability, lameness, pain and the development of osteoarthritis.

Has my dog injured his CCL?
The diagnosis of CCL injury is based on clinical history of the lameness and physical examination by a Veterinary with gait analysis, and radiographic investigation of the stifle joint. Additional tests may sometimes be required eg joint fluid analysis, arthroscopy, MRI etc.

What treatment is required?
Some smaller patients, with normal anatomy, may fair well without surgical treatment. Management of these cases can involve restricted activity levels, weight management, anti-inflammatory pain relief, physiotherapy and hydrotherapy.

The vast majority of dogs with CCL injury will have ongoing progressive stifle pain, instability and lameness and require surgical treatment to improve their function.

What surgery can be performed?
A variety of surgical options are available to treat CCL injury. These include options that aim to passively restrain abnormal movements in the stifle joint, eg ligament replacement techniques with tissue grafts or sutures. Alternative recent techniques are aimed at actively opposing abnormal movements and changing the way forces act through the joint (eg tibial plateau levelling osteotomy, TPLO).

A full discussion with your veterinary surgeon will allow you to understand the risks and benefits of available surgical techniques, and allow an informed decision to be made as to the option which will be most beneficial to your dog.

Post operative management ?
All patients undergoing surgical treatment will require exercise restriction for 6-12 weeks. The aim is for a full return to exercise 3-4 months following surgery. Exercise restriction is most important in the first 6 weeks post surgery, when no free activity including no running, no jumping, and no climbing stairs is allowed. Lead exercise must even be enforced in the garden for toilet purposes.

It is normal for patients to be re-examined 6 weeks after surgery for assessment, and often radiographs will be taken. This allows us to document how your dog is recovering and give advice on future activity and return to function. In the majority of cases dogs can normally start to increase their activity levels after this assessment.