What Causes a torn ACL ligament in a dog?

The anterior cruciate ligament (ACL) - otherwise known as the cranial cruciate ligament - is a fibrous band of tissue that helps to connect the thigh bone to the lower leg bone. 
Injury to the ACL is pretty common in younger (1-3 years old), larger, active dogs.  There are many factors that contribute to the tearing of the ligament.  Unlike people, where a traumatic event is a major cause, most times a dog's ACL will tear unexpectedly and without an obvious cause.

How Can We Fix It?

There are a few different, common procedures that are done to fix the ACL tear.  We've listed them below, as well as some pros/cons of each, and their relative prices.

TPLO:  The tibial plateau leveling osteotomy surgery has been around for over 25 years and is considered to be the gold-standard surgery.  The idea behind it is to change the angle of the top of the tibia so that the femur - sitting above it - no longer slips backwards.  In a healthy leg, the ACL is suppose to prevent this slippage but when it tears, the movement causes pain and inflammation.  The TPLO surgery has a very high success rate (~95%) and is our favored procedure. At our clinic, the total cost is $4,400. For more information on this procedure, click here.

CBLO:  The cora based leveling osteotomy surgery is the newest way of repairing a torn ACL in the dog, and so there is not as much information out there for the public.  It has the advantages of both the TPLO, by leveling the tibial plateau, and the TTA, by moving the patellar tendon forward.  This surgery is well suited for dogs that are still growing or dogs with an excessive tibial slope.  For most other patients, we still recommend the TPLO as we have a much longer track record of that surgery. At our clinic, the overall cost of the CBLO procedure is $5,000.

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Lateral Suture (Extracapsular Technique):  Other words for this include lateral fabellar suture, lateral suture stabilization, and "fishing-line technique".  This surgery has been around for about 40 years.  This tends to be one of the more common ways to repair an ACL tear because some general practitioners feel comfortable performing it and it's quicker and less invasive to perform.  Surgical results have been mixed, however. This surgery is best suited to smaller patients - perhaps dogs under 30 lbs - but we still do recommend the TPLO as the preferred surgery in patients of all sizes. The total cost at our clinic of the extracapsular technique is $2,500.

TTA:  The tibial tuberosity advancement has been around for over 15 years.  The idea behind this surgery is to move the patellar tendon forward so that the forces acting on the knee cancel out - the backwards slope of the tibia pushing the femur backwards is counteracted by the patellar tendon pulling the femur forwards. This surgery has a somewhat quicker recovery but slightly worse long-term results compared with the TPLO. We no longer offer this surgery.

Tightrope (IsoLock CrCL):  Another variant of this surgery is known as the “Tightrope technique”.  This surgery has been around for at least 10 years.  The idea behind it is to recreate the torn ligament with an artificial one. We use a very high strength filament, designed for use in human joint 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. Due to the higher infection risk but similar outcome with the TPLO, we no longer offer this surgery.