What Causes This?

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.  The tearing of this ligament is common in dogs.  It most commonly happens in younger (1-3 years old), larger, active dogs.  There are many factors that contribute to the tearing of the ligament in dogs.  Unlike people, where athletic trauma is a major cause, dogs sometimes will tear their ligament seemingly with no reason.  What is happening is that over time, the ligament is breaking down and getting weaker.  Then, one day without warning, it partially or fully tears. 

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.

IsoLock CrCL:  Another variant of this surgery is known as the tightrope technique.  This technique has been around for about 5 years.  The idea behind this surgery is to recreate the torn ligament with an artificial one.  The material used is high-strength and is used extensively in human surgeries.  It is resistant to stretching or breaking.  The artificial ligament is passed from the femur to the tibia in a location that is isometric - meaning that it is under equal stress when the leg is flexed or extended.  The reported complication rates and clinical outcomes are similar to the TPLO surgery.  The benefit to this surgery is that no bones are cut, so the procedure is less invasive or painful.  Also, it tends to be less expensive.  The overall cost at our clinic is $2500. 


TPLO:  The tibial plateau leveling osteotomy surgery has been around for about 20 years.  The idea behind it is to change the angle of the tibia so that the femur above it no longer slips backwards.  The ACL is suppose to prevent this from happening but when it tears, the femur tends to slip backwards from the tibia and this causes pain and inflammation.  This surgery has a very high success rate.  The downside is cost.  At our clinic, the total cost tends to be about $4500.

TTA:  The tibial tuberosity advancement has been around for over 10 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.  The tendon is moved forward by cutting the place it connects to on the tibia and pushing it forward.  The cut is made in a non-weight bearing area of the bone, and so the recovery tends to be faster and less painful.  Because this surgery costs the same as the TPLO but has slightly worse results, we currently do not offer this option.

Extracapsular Technique:  Other words for this include lateral fabellar suture, lateral suture stabilization, and "fishing-line technique".  This surgery has been around for about 50 years.  This used to be one of the more common ways to repair an ACL tear because many general practitioners feel comfortable performing it and it tends to be less expensive overall.  However, recent studies have found that while the surgery does lead to better outcomes than doing nothing, it is inferior to the other surgeries listed here.  This is for a few reasons:  1)  The implanted wire runs around soft tissues that break down over a few weeks to months, causing the implant to become loose, 2) The nylon used tends to stretch over just a few days, and forever becomes loose and in-effective, 3) The positions on the knee where the wire is placed have different degrees of stress acting on it depending on flexion or extension of the knee - which is not ideal.  This surgery is best only performed in dogs under 40 lbs, as the nylon is more likely to break in larger animals.  The overall cost at our clinic for this procedure is $1,000.