Lateral Fabellar Suture in Dogs

Rupture of the cranial cruciate ligament within the stifle (knee) is a common source of lameness in the dog. The cranial cruciate ligament (CCL) stabilizes the stifle and stops the femur (thigh bone) sliding forward over the tibia (shin bone). This causes severe lameness and potential damage to the menisci (cartilage pads) within the stifle, which is painful and predisposed to arthritis. 

A lateral fabellar suture is a surgical method of stabilizing the stifle. It is what's called an 'extracapsular' technique, because the suture is external to the knee joint itself. As such this means it's not as invasive as other techniques. However, the lateral fabellar suture repair is best suited to small-sized dogs since the suture itself can stretch or break if a large or heavy dog puts too much weight on it. 

Lateral fabellar sutures can be placed by a skilled surgeon in first opinion practice or at an orthopedic referral center. 

First, CCL rupture must be diagnosed using a combination of radiographs and dynamic testing of the stability of the stifle joint. The patient is then assessed for suitability for a lateral fabellar suture repair by considering their body weight, activity level (very active dogs are less suitable) and the anatomy of the stifle joint. 

The patient is given a general anesthetic and the affected leg clipped up and aseptically prepared for surgery. The surgeon makes a curved incision over the stifle to expose the joint. A small incision is made in the joint capsule in order to visually inspect the menisci and check for damage. If the meniscus is torn then it is trimmed back to alleviate further discomfort. 

A small tunnel is drilled through the tibial plateau. Then a loop of strong nylon suture is passed behind the lateral fabella which sit behind the stifle joint. The suture is then passed through the tunnel and tied so it forms a figure-of-8. The skin incision is sutured and the patient woken. 

In the right patients, this technique provides support until scar tissue forms which creates permanent stabilisation of the joint. It is highly successful in smaller dogs (typically less than 10 kg or about 22 lbs) or less active medium-sized dogs. 

It is essential the dog is rested postoperatively, because too much activity could lead to failure of the implant. Likewise if the patient is too large or heavy then the suture may slacken or snap, and lameness recur. 

Another potential complication is failing to identify a torn meniscus. If this is not trimmed back the flap of cartilage can cause pain and discomfort so the dog remains lame despite a successful stabilization of the joint. 

There are many different procedures which stabilize a CCL rupture, but these are all more invasive and/or involve metal implants or remodelling the bone. Accordingly, these are more complex and almost certainly referral to a specialist surgeon is required. 

Joint surgery is painful so pre and postoperative pain relief is essential, for as long as the dog shows signs of discomfort. For a couple of days after surgery, holding an ice pack on the stifle for five to ten minutes can alleviate swelling. By day three, the owner can gently bend and flex the stifle to maintain muscular condition in the limb. 

For two months, only gentle lead walks are permitted. Running, jumping, or twisting activity is strictly forbidden. The surgeon may also suggest various physiotherapy exercises to maintain muscle mass and speed rehabilitation. 

A gradual return to normal function takes approximately six months. 

Surgery in first opinion practice for this condition varies in price, but expect to pay $800 to $1,500. At a referral center with 24 hour nursing care and a board certified specialist surgeon and anesthetist, expect a cost of $2,300 to $2,500.

Successful surgery leads to scar tissue formation which permanently stabilizes the joint. However, the rubbing of the femur against the tibia may have already caused damage (prior to surgery) which results in the development of early arthritis. 

Implant failure is a possibility in heavy dogs or if too much stress is placed on the stifle, such as occurs when the dog runs or jumps. 

However, lateral fabellar sutures remain an excellent option to stabilize the stifle joint in smaller dogs, and the surgery is less invasive and painful than other options. 

CCL rupture is a common problem. It is thought there is some genetic tendency to rupture as the condition is more likely in certain breeds such as Labradors and Rottweilers. 

To reduce the risk of CCL rupture it helps to keep the dog a healthy weight. Also, it's advisable to warm the dog up with a lead walk, prior to strenuous off-leash exercise that involves twisting, turning, and running.