ACL Basics

In the event that you are blissfully unaware of your ACL's or their purpose in your life, well then, congratulations and count your blessings. Over the course of my life, I've watched just enough professional sports to learn everything I thought I would ever need to know about the ACL - it's inside the knee, it appears to hurt like hell when you break it, and doing so can be the end of an otherwise promising career. That's why I never played any pro sports. Too dangerous. The fact that I've never been quite big enough, strong enough, or athletic enough is entirely beside the point. Of course as I recently discovered, you don't actually need to play with the pros to do pro-level damage. Turns out, if you hit it just right, you can ruin your knee right in the comfort of your own home.

But before I get to that story, let's get everyone up to speed on the tissue at issue.

The ACL (Anterior Cruciate Ligament) is a critical ligament in the knee that runs from the back of the femur, through the middle of the knee to the front of the tibia. Under normal operating conditions, it helps prevent the knee from bending backwards and provides rotational stability. Partial tears are possible but most reported ACL injuries are complete tears. In that case, the knee is allowed to move in directions that it was not intended to move. Short term instability and long term degenerative damage are the result. Even a partial tear in the ACL has difficulty healing in part because the blood that clots at the sight of the tear (in an attempt to create a bridge of sorts on which new cells can grow) is repeatedly washed away by the fluid in the knee. A complete tear will never heal on its own. In some cases, a fully torn ACL can be repaired but this is very rare, and typically requires that the tear is right at the bone. There are only a few surgeons in the world even attempting full tear repairs. In the vast majority of cases the ACL is instead "reconstructed", that is, the damaged ACL is cut out and new tissue is attached to the knee. This is obviously a pure “gut and replace” operation, but somehow that doesn’t sound quite as nice as a "reconstruction".

Although ACL reconstruction is a relatively common, highly successful operation, it does not make the knee like new again. The replacement is not routed the same as the native ACL but instead installed in such a direction that it can approximate the stabilizing forces of the original. The replacement graft will never provide quite the same degree of stability as the pre-injury ACL and although a successful graft will eventually revascularize and regenerate, it will not contain or regrow the nerves which help the brain identify and control the movement of the knee. The purpose of reconstruction is solely to regain some of the mechanical stability in the knee necessary for certain activities and to limit the unstable movement that contributes to further damage and long term degeneration issues. Even after the most successful of ACL reconstructions, the knee is never quite the same.

In short, it's not a good idea to tear the ACL.

The ultimate goal of course is to rebuild and strengthen the surgically altered knee in ways that will help make up for the shortcomings of the reconstructed ACL. The rest of the entries to follow herein will describe my own ACL injury, the ensuing surgery, and my viciously held aspirations for recovery.