Injury to the cranial cruciate ligament is the most common cause of lameness in the hind limb of dogs. This ligament is the main stabilising ligament in the stifle or knee. Tearing of the ligament can be caused by trauma, gradual degeneration, obesity, breed, genetics and conformation (abnormal tibial shape).

When the ligament tears it is extremely painful and most dogs limp and may have trouble walking if both stifles are affected. Significant ligament tears result in the stifle becoming unstable making it harder for the dog to walk. Dogs that also damage their meniscus (a soft C-shaped cartilage between the femur and tibia bones) can be in a lot of pain and are often reluctant to bear weight on the leg. Repeated small ligament tears can cause lameness that comes and goes over time. The ligament will eventually rupture. This process can take months or years. Therefore, once the ligament starts to tear, this process continues causing pain and lameness until eventual rupture.

In cases of early small tears, some dogs improve with rest and pain relief. For those that don’t improve, surgery is likely to be required. In cases of significant or complete ligament tears, surgery is recommended to resolve the lameness.

Before scheduling surgery, the diagnosis or problem needs to be confirmed, this requires examination of your dog's knee by a vet. If your dog is in pain your vet may need to sedate or anaesthetise him/her to do a thorough examination. Radiographs are usually taken at this time to confirm the diagnosis, rule out any other problems, to check for any underlying osteoarthritis and for surgical planning. Occasionally joint fluid will also be withdrawn from the joint and analysed.

There are a lot of different surgical techniques used to treat cruciate disease in dogs and tibial osteotomy techniques are gold standard. Of these, I prefer the Triple Tibial Osteotomy technique (TTO). In very small dogs I perform either a closing wedge osteotomy technique which is similar to the TTO, or an extracapsular suture repair. Your referring vet can help you with the decision making process.

Surgery involves removing damaged ligament fibers and meniscus from the joint. Then a wedge of bone is removed from the tiba and the gap is closed down. This changes the biomechanics or forces in the joint allowing the dogs to walk normally without having a cranial cruciate ligament. The bone is secured in its new position with a plate and screws. It takes approximately six to eight weeks for the bone to heal. For this reason your dog's activity needs to be reduced and controlled during this time (refer to the Cruciate post surgery care instructions).

In the case of an extracapsular repair, a suture (called a prosthesis) is then placed on the outside of the joint to mimic the damaged ligament and stabilise the joint.

Cruciate Ligament Surgery is generally very successful with the vast majority of cases improving significantly, often within 6 to 12 weeks of surgery. Physical therapy, pain relief, keeping your dog lean and joint supplements may help to maximise the outcome postoperatively.

Progression of osteoarthritis will eventually occur and this may cause stiffness after exercise and rest.

What Can Go Wrong?

Cruciate Ligament surgery is a major surgery. Whilst the vast majority of procedures result in success, there are a number of potential complications that can occur. Every step possible is taken along the way to minimise the risk of complications and therefore maximise the chances of a good outcome.

Potential complications include:

• The bone sometimes does not heal quite as fast as expected. Some dogs do not progress as well as we would like in the first six weeks, and follow up radiographs at this time demonstrate the slow bone healing. These dogs usually begin to improve in the following six weeks.

• The change in shape of the knee puts additional strain on some of the structures around the knee. The body adapts or remodels to take account of these new strains, but this can take several months. Too much strain/exercise in the early stages after the operation can lead to damage to some of the other ligaments in the knee, failure of the implants, or even to bone fractures. This risk is especially present in the first six weeks after surgery. Occasionally a second surgery is required to resolve the problem.

• Complex orthopaedic surgeries have a higher risk of postoperative infection than shorter, simpler surgeries. We take every precaution to minimise this risk at the time of surgery.

• The menisci (cartilage pads) may be normal at the time of surgery, but there is a chance of meniscal injury in the weeks and months that follow surgery (so called ‘late meniscal injury’). This can sometimes account for a setback when there has been good improvement in the first few months. A further surgery may be required to remove the cartilage tear.

Once a dog/cat is confirmed as a surgical candidate, a date for surgery will be arranged. Cruciate ligament surgery is an elective procedure, this means that it is not urgent but it should be performed prior to the development of osteoarthritis. Your vet can help you decide on the timing of surgery.

Most dogs are well enough to go home within 24 hours of surgery. We supply pain relieving drugs +/- antibiotics.

Crate/pen confinement is essential in the first six weeks and we advise restriction to downstairs in the house (no stairs) with only the shortest possible lead walks for ‘toilet breaks’. Most dogs use the leg within a few days of surgery and improve steadily thereafter. Physical therapy (see below) is beneficial and can be started before surgery or within the first week after surgery. Your vet will usually check your dog a few times in the two weeks following surgery. At week six, your vet will re-examine and admit your dog to hospital as a day patient to obtain radiographs (usually under sedation or anaesthesia). Please alert your vet or your surgeon sooner if progress is not satisfactory or if there are other complications. If all is going well at week six, short lead walks with a gradual increase in activity is advised. A further check around week twelve may be required and if all is going well at this stage we will advise return to normal activity.

What you need to do BEFORE the day of surgery:

• Read the Post Surgery Care Instructions for Cruciate Repair (link below).

• Have at least one area to confine your dog organised in your home (eg a crate in your bedroom, tethered to a desk in your office and/or a pen in the lounge). You may need to purchase a crate, pen and/or gates and non-slip matting and get your dog used to this new arrangement.

• Arrange a skin check, and if necessary a blood test, 7-10 days before surgery. If your dog has any skin lesions, a medicated body wash and antibiotics may be prescribed. If skin lesions are found on the day of surgery, this may result in the procedure being rescheduled to a later date due to the risk of infection.

• Wash your dog the weekend or day before surgery. This will reduce the time spent under anaesthesia cleaning your dog on the day of surgery.

• Consider “enrichment” for your dog in the postoperative recovery period (eg stuffed toys, sniffing games, food dispensing toys, chewing and licking time etc).

• Arrange Physical therapy appointments before the day of surgery as there may be a wait for an initial appointment and timing is of the essence in these cases (see physical therapy contacts below).

View, download or print these post surgery care instructions for cruciate ligament surgery.

Physio and Rehab contacts list