What Causes a Torn Cruciate Ligament in a Dog?
The cruciate ligament is a band of connective tissue connected from the thigh bone to the shin bone, acting to stabilize the knee joint. The most common ligamentous tear in dogs is the Cranial Cruciate ligament (CCL), which is equivalent to the Anterior Cruciate Ligament (ACL) in people.
Injury to the Cranial Cruciate ligament is most common in middle-aged (4-8 years old), overweight, larger breed dogs. There are many factors that contribute to the tearing of the ligament, but unlike people, where a traumatic event is a major cause, most times, a dog's ACL tears due to aging of the ligament and small repetitive injuries, unexpectedly tearing without an obvious cause.
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How Can Cruciate Injuries Be Treated?
There are a few common surgical procedures that we use to stabilize the knee after the cruciate ligament has been torn. We've listed them below, as well as some pros and cons of each.
Tibial Plateau Leveling Osteotomy (TPLO): The TPLO surgery is currently considered the gold-standard procedure for large and giant breed dogs. Since dogs walk on their toes, their tibia plateau is at a downward slope that causes the tibia (shin bone) to shift forward (tibial thrust) relative to the femur (thigh bone) when the cruciate ligament is torn, causing pain and inflammation. By cutting the tibia and reducing the downward slope of the tibia joint angle, the procedure halts the forward movement of the tibia. The TPLO surgery has a very high success rate, with around 95% of dogs having a full recovery. This is our preferred procedure for most adult dogs over 40 lbs.
Lateral Suture (Extra-capsular Technique): This procedure has also been referred to as lateral fabellar suture, lateral suture stabilization, and "fishing-line technique." This surgical procedure has been around for a long time and still remains one of the common ways to stabilize knees with cruciate injuries. The surgery is best suited for smaller patients, such as dogs 30 lbs and under. It is less invasive and tends to be a little quicker to perform. Results can be mixed in larger active pets, but most dogs under 30 lbs do very well.
Tibial Tuberosity Advancement (TTA): The TTA surgical procedure advances to the patellar tendon insertion on the tibia, causing increased pull on the tendon and quadriceps to counteract the tibial thrust created by the downward slope of the tibial plateau. Recovery tends not to be as good as with TPLO surgery.
Tight Rope Technique: The Tight Rope technique is a variant of the lateral suture technique where a braided polyester material is approximate the torn cruciate ligament and acts as an artificial ligament. It has some advantages over the lateral suture in that its anchor points are isometric bone tunnels; as such, the technique can be used in large and giant breed dogs with similar success at TPLO surgery. The benefit to this procedure is that no bones are cut, so it's less invasive or painful. The downside is a higher infection risk compared with the TPLO. We use this procedure in cases where clients prefer a less invasive repair that has similar outcomes to TPLO surgery in large and giant breed dogs.