Techniques

The most common cause is progressive degeneration of the ligament, the reason for which is still elusive despite years of research. Abnormal conformation and gait, shape of the tibia (shin bone), obesity, and lack of fitness have been suggested as a cause but not proven.

For the majority of dogs, surgery is the only way to return them to good function, not braces or medications or herbs or physical therapy or wishing or hoping!

Lameness is the main symptom of cruciate rupture, and this can be sudden in onset or more gradual. The severity of lameness can also vary from mild to almost non-weight-bearing. This is often related to the type of cruciate ligament disease:

1 – Partial rupture:

Typically seen in young, large breed dogs. Lameness can be mild initially but becomes worse with progressive ligament degeneration. Usually, the ligament will go on to rupture completely.

2 – Complete rupture:

This is usually seen in middle-aged dogs, and the ligament may rupture during normal exercise. Lameness is usually marked, and this can improve initially but typically dogs remain with a limp.

3 – Traumatic rupture:

Sometimes there is a history of trauma such as a road traffic accident or getting a leg stuck when jumping over a fence. Lameness is usually sudden in onset and severe.

Before surgery, an x-ray of the stifle is taken to measure the angle at the top of the shin bone, called the tibial plateau angle. The goal of the surgery is to reduce this angle so that dynamic joint instability (cranial tibial thrust) is eliminated. This is usually accomplished by creating a post-surgical angle of between 4 and 10 degrees, an angle not much different than is found in the human knee. In most cases the surgical procedure starts with an exploration of the inside of the stifle joint. The purpose is to assess the meniscal cartilages for any possible damage. Damaged cartilage must be removed if the dog is to regain normal pain-free function.

The TPLO procedure itself involves the use of a curved saw blade to make a curved cut on the inside, or medial, surface of the top of the tibia. The cut top portion is then rotated to create the desired tibial plateau angle. A locking bone plate is then placed on the bone to hold the two pieces in their new alignment.

Aftercare following TPLO surgery is very important, and rehabilitation can take 2-3 months. Courses of pain medication and antibiotics are prescribed at discharge. If the dog tends to excessively lick the wound it may be necessary to use a plastic collar. Rechecks are necessary within the first two weeks to check the wound and remove any sutures.

Exercise must be very restricted for the first few weeks to allow healing, and is primarily for toileting purposes. The dog must be kept on a leash or harness to prevent strenuous activities such as running, jumping or playing. At other times confinement to a small crate or a small room is necessary to avoid jumping and climbing. After a few weeks, exercise may be gradually increased in a controlled manner (on a leash). Physical therapy may also be recommended.

A check-up will be carried out six to eight weeks after the operation, to monitor the function of the leg and knee. X-rays are obtained to evaluate healing of the bone cut (osteotomy). Depending on progress, advice will be given about increasing exercise. Further clinical and radiographic examination may be necessary on an individual case basis.