Torn cruciate ligaments are the most common cause of back leg lameness in dogs. We see the injury in dogs of all breeds, sizes and ages. The torn ligament can be a ‘partial’ tear, often producing a mild recurring lameness, or it can be a complete tear that usually results in a severe lameness. It can occur while the dog is running or jumping (high impact activity) or can happen during something as simple as a walk. When the ligament tears it can also result in damage to other important parts of the knee (the menisci) which also results in ongoing pain.
Unfortunately once the ligament is torn it cannot repair itself, and partial tears will always progress over time to become a complete tear. Without intervention the knee joint remains unstable, develops arthritis and becomes thickened due to scar tissue. Long term this leads to degenerative arthritis and pain for the dog which cannot be reversed.
There are 3 options for management of cruciate ligament injury, although not all are appropriate to every size dog.
1. Conservative management
Conservative management is really only an option for dogs less than 15kg with partial tears and no menisci damage.
- Strict rest for 6 weeks – this involves keeping the dog confined to a small area (2m x 2m) and only taken out (on a lead) to go to the toilet.
- Pain relief – tablets are usually given for 2-4 weeks to keep the dog comfortable.
- Relies on the dog’s body to stabilise the knee joint through the formation of scar tissue around the joint. Thus if the dog is too active in the early stages the scar tissue formation is too ‘loose’ to provide the required stability. Also if the dog is too large the scar tissue will not be strong enough.
- Requires no surgical intervention
- Can perform surgery afterwards if not successful
- Does not allow assessment of other damage inside the joint
- Requires strict rest which can be difficult for some pets and owners
- High failure rate due to inability to confine adequately
2. Lateral Suture Technique
This method has been around for many years and has been very successful. It can be performed in dogs of any size and was previously the only surgical option available. Post-operatively there is still a need for strict confinement to allow the joint to heal.
- This technique involves placement of a thick nylon material (similar to fishing line) under the skin on the outside of the joint. The material is placed through holes drilled in the bone, pulled tight and secured by tying a knot or placing special metal crimps.
- This technique stabilises the joint because the nylon mimics the torn ligament.
- Allows inspection of the joint for other damage
- Less expensive surgical option
- If the dog is too active or does something too boisterous during the healing stages then it can stretch or break the nylon resulting in the surgery failing
- Slower return to walking than other surgical options
3. Tibial Wedge Technique
This is one of the newer methods of cruciate ligament repair developed over the past 15 years, and currently regarded as the ‘gold standard’ for cruciate ligament repair. This is our preferred procedure.
- A tibial wedge involves removing a measured triangle shaped piece of bone from just below the knee joint. The left over defect is then reduced and the bone secured with a metal plate and screws.
- This technique alters the forces in the joint when the dog puts the foot to the ground. As a result there is no longer any forward and backward instability in the knee joint. The surgery does not repair the torn ligament, but instead eliminates the need for it altogether.
- Allows inspection of the joint
- Earlier return to function post-operatively
- Most advanced techniques to date
- Dog can’t ‘redo’ the injury as we eliminate the need for the ligament (compared with the lateral suture technique which can be broken or stretched post-operatively)
- More expensive
- Still requires confinement for a period of time to prevent to dog doing anything ‘silly’ that might result in failure of the implant
- Regardless of the surgical technique performed it takes 4-5 months before the dog is running without any sign of lameness or injury, although most dogs can resume normal off-leash activity after 8-10 weeks.
If you have any questions about cruciate ligament injuries, please don't hesitate to give us a call at the clinic.