The cruciate ligaments are 2 ligaments that run through the stifle (knee) joint forming an ‘X’ when the stifle is viewed from the side. They are called the cranial cruciate (CCL) and the caudal cruciate ligament.
Partial or complete rupture of the cranial cruciate ligament is a very common injury in the dog and also occurs in cats. Rupture causes instability of the stifle (knee) joint. This also causes acute pain and over time leads to degenerative joint disease or osteoarthritis. Quite commonly, there is also a tearing of the meniscus (cartilage) within the joint which occurs concurrently with or following cruciate ligament rupture, this is a very painful injury.
Diagnosis may be possible at the initial consultation. However most awake patients are sore and nervous, and tense the muscles of the leg, making it impossible to feel the instability in the joint. This is particularly true for large dogs, well muscled dogs and dogs with partial CCL tears. Usually sedation or a general anaesthetic is needed to allow the veterinarian to check for this instability and radiographs are performed to assist in making this diagnosis.
Without surgical repair, dogs with CCL lameness rarely return to pre-injury activity levels without recurrent lameness, and over time will develop degeneration and arthritis within the joint. Surgery is therefore recommended for any dog with CCL damage. In saying that, some of our smaller patients, for example those <5kg, may not require surgery, 6-8 weeks rest, pain relief and weight management may suffice.
The surgical procedure used depends on the size of your pet and any conformational issues they may have:
For smaller dogs surgery may involve the following:
- Opening the joint to examine the menisci (cartilage cushions in the knee) for damage which can occur as a result of the CCL injury. Removing any damaged cartilage and the torn ligament. Tightening and suturing closed the joint capsule.
- Replacing the function of the ruptured CCL with a strong nonabsorbable suture material external to the joint
- Closing the skin incision, with or without skin sutures.
In our larger dogs:
- The stifle joint is also opened and the cruciate ligaments assessed, debrided if necessary and the menisci is released or debrided if needed.
- What is unique to our larger dogs is that due to their size a metal plate is needed to stabilize the joint. This metal plate is placed after cuts are made into the tibia to change the conformation of the joint and remove the need for a cruciate ligament.
Pain relief medication is given to assist recovery and to make the patient as comfortable as possible.
- A minimum of 3 months recovery time post operatively.
- Anti-inflammatories will be used in the initial stages of recovery and if necessary throughout the remainder of your pet’s recovery.
- We will also begin a course of Pentosan injections one (1) week after surgery. This involves giving an injection once a week for four (4) weeks and helps minimise the development of arthritis in the injured joint.
- It is extremely important that your pet’s exercise is strictly controlled during healing. We will discuss this further with you but basically it means no running off-lead or jumping for the next six (6) weeks.
- Skin sutures will be removed in two (2) weeks.
- At 6 weeks a follow up xray is performed to assess healing of the surgery site.
- Reintroduction to exercise should be slow, progressive and controlled.
- It is important that your pet maintains a healthy weight. Obesity greatly increases the risk and severity of degenerative joint disease and also the risk of a similar injury occurring in the other hind leg. Please feel free to discuss diet with us.
The long term outcome for most patients is good. This is influenced by the activity level of the dog, the dog’s size and whether the dog is overweight – large, active, overweight dogs have a poorer prognosis. A significant percentage of patients injure the CCL in the opposite knee within 3 years.