Cranial Cruciate Ligament Rupture / TPLO

Prognosis for dogs that undergo surgical repair is good with improvement seen in 85-95% of cases.

Overview

The knee of a dog is built much as our own knee. Like people, dogs can injure any of the ligaments in their knee. The most common injury is a tear on the anterior cruciate ligament (ACL)

The cranial cruciate ligament sits in the knee to help stabilize 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.

Signs

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

Predispositions

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

Diagnosis

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.

Management

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 stabilization
• Medical management of osteoarthritis

Surgery

There are a number of surgical techniques used to repair the cruciate ligament and/or menisci. Long term studies have shown that a TPLO (Tibial Plateau Leveling Osteotomy) surgical repair is considered the gold standard for treatment of cruciate ligament injuries with the lowest rates of complications and superior long-term function.  The TPLO procedure is suitable for most dogs.

Tibial plateau leveling osteotomy (TPLO)

The TPLO is an orthopaedic surgery performed following the rupture of a cranial cruciate ligament within the knee.

The surgery helps to stabilize a knee, not by replacing the ligament but by replacing its function. The surgery changes the angle of the top of the tibia, so it has a level tibial plateau, which decreases the sliding motion of the joint. It allows the other muscles to support the knee without a cranial cruciate ligament.

While under general anaesthesia, the knee joint is exposed, opened and the joint examined. Any damaged menisci or other injuries are assessed and addressed where relevant.

A specially designed bone plate and screws are attached to the tibia to stabilize the bone and promote healing.

What to expect after surgery

• A mild amount of swelling for the first week
• Mild bruising around the surgical site
• Preventing licking at the surgery site
• Restricted exercise plan
• Leash walking only for two months
• Follow up radiographs 6-8weeks if required

Initially, your pet may require you to use a sling to assist them walking over surfaces to the toilet within the first 2 weeks to prevent them from falling on their leg.

Rehabilitation

Studies show that physical therapy can improve the recovery process following this procedure. Your veterinarian may prescribe an exercise program specifically for your pet and advise you when to start.

Physical therapy examples:

• Passive motion
• Swimming
• Balance exercises
• Leash walking

Benefits of rehabilitation exercise:

• Help maintain good body condition
• Speeds recovery
• Prevents further injury
• Improves fitness and health
• Potentially decreases the onset of osteoarthritis
• Improve mood
• Decrease pain
• Increase flexibility
• Improve blood flow

Prognosis

Dogs that undergo surgical repair have a good to excellent prognosis in greater than 90% of cases.

Pets that sustain a cruciate ligament injury and undergo surgery, are still prone to arthritis and other joint problems. But surgery allows them to continue to a healthy and active lifestyle. Studies suggest 93% of pets can return to full normal function within a year after surgery.

Studies also show that approximately 50-60% of dogs will rupture the other cruciate ligament within 2 years of each other.

Although surgery is performed to minimize complications, they can still happen from time to time, which may require further surgical intervention.

• Infection rates occur in 3-5% of patients
• Implant failures occur in 2% of patients
• The meniscal injury occurs in 5-15% of patients

Long-term management

The long-term recovery success relies on other forms of management:

Prevention

Tips to help prevent a cruciate ligament rupture:

• Prevent obesity as this can lead to strained joints
• Provide regular exercise such as swimming to strengthen the muscles around the knee
• Stick to exercise that does not require a lot of twisting action or sudden stopping
• Always warm-up before strenuous exercise such as long hikes and running

A pet that is suspected of a cruciate ligament rupture should seek veterinary attention immediate