The cranial cruciate ligament sits in the knee to help stabilise the main leg bones. It can become damaged and rupture completely or partially, causing inflammation, pain and arthritis. Unlike humans where the cruciate ruptures from one traumatic event, dogs tend to rupture their cruciate ligament following weakening over time.
Clinical signs of a cruciate ligament rupture include lameness with very little weight bearing. An injured dog usually holds the limb up. This type of injury typically requires surgery.
Occasionally, the cartilage within the knee joint called menisci can become damaged. These menisci act as a shock absorber between the leg bones and can cause discomfort when damaged.
Common signs of a cruciate ligament rupture:
- Sudden, severe limping on one rear leg
- No or little weight bearing on the leg after an injury
- Mild or intermittent limping in the case of a partial tear
- Swelling of the knee may occur
- Difficulty rising or jumping
Predisposition to cruciate ligament rupture:
- Large and giant breeds are at a higher risk than small breeds
- Young, active dogs are at higher risk
- Overweight dogs suffer higher levels of stress on their joints
- Dogs that have been hit by cars, attacked by other dogs or suffered other forms of trauma
- Dogs that have previously injured a cruciate ligament in one knee are at an increased risk of injuring the ligament in the other knee at a later date
- Dogs with relatively long legs
- Dogs that are spayed or neutered at a very young age may be at a relatively higher risk
Cranial cruciate ligament rupture can be diagnosed from a thorough history, physical examination, x-rays or an arthrotomy (surgical investigation of the joint). Your veterinarian may perform stifle manipulations such as the drawer or tibial thrust test to determine the degree of joint laxity.
Treatment of a cruciate ligament rupture may consist of:
- Exercise restriction and cage rest for several weeks (8+ weeks). This may be sufficient in small dogs and cats.
- Weight loss
- Surgical stabilisation
- Medical management of osteoarthritis
There are a number of surgical techniques used to repair the cruciate ligament and/or menisci. We will determine the appropriate surgical technique based on the size of dog and degree of damage.
Your pet will remain in hospital until it is fully recovered from the anaesthetic and when its pain is under control.
Homecare following the procedure is extremely important to achieve the best outcomes. Excessive activity can result in poor healing or complications. It is important to follow the strict confinement regime to avoid surgical complications.
Prognosis for dogs that undergo surgical repair is good with improvement seen in 85-90% of cases. Surgery complications are uncommon but may include meniscal injury, infection, implant failure and soft tissue swelling.
Although surgery can slow the progression of arthritis, it is still common for dogs to develop arthritis later in life.
Studies also show that approximately 50% of dogs will rupture the other cruciate ligament within 2 years of each other.
Once the ligament is torn or ruptures, the knee becomes unstable and inflamed, leading to pain and osteoarthritis. Surgical stabilization is required in a large proportion of cases to avoid debilitating osteoarthritis and chronic pain.
At Highton Veterinary Clinic we do several surgical procedures including the TPLO (Tibial Plateau Leveling Osteotomy), and DeAngelis (Lateral Suture) techniques.