So imagine you have this tall, slender vertical structure. Except unlike most tall, slender vertical structures, this one can move. Towards the base of the vertical structure, where structural integrity is critical, you’ve got four cables holding a moving joint together, enabling that moving joint to articulate in one direction but not others. Each cable is carefully bolted into place.
Now imagine you have a somewhat more short, squat vertical structure than the “normal” example I just described. Except in this structure one of those four cables that is carefully bolted into place has been detached, frayed about halfway up, and then reattached with duct tape instead of a bolt.
The first example is a normal person’s knee. The second example is my knee. And that frayed cable is my posterior cruciate ligament. Allow my to illustrate:
This is a way dumbed-down rear diagram of a knee*. The white parts are the bones above and below the knee joint. The green parts on the sides are the medial collateral (MCL) and lateral collateral (LCL) ligaments. The light blue part is the anterior cruciate ligament (ACL), the one that gets all the press because it’s kind of important but relatively easy to damage. But it can also be fixed. The red part, behind the ACL but in front for us since this is a rear view, is the posterior cruciate ligament (PCL).
*If the intelligent design crowd is correct, I’m going to have lots of questions for the all-knowing designer about why he or she designed human knees like this.
In the space between the white parts is meniscus and cartilage and what not, but you can’t see that because this is the dumbed-down version, and I only have so much patience for making really lame graphics.
Like the ACL, the PCL is also kind of important, as it stabilizes the knee, keeping it from hyperextending. It’s a larger ligament and relatively hard to damage. Unfortunately, situated as it is behind the ACL, pretty much smack in the middle of the knee joint, most surgeons think it’s not worth repairing if injured because so much damage would need to be done just to get to it.
A few years ago while playing soccer, I stepped in a hole while trying to slow down from a full sprint. My knee hyperextended, tearing the PCL from it’s attachment point and splitting it down the middle for about half its length and tearing some of my meniscus in the process. My orthopaedist told me it was quite a split, as that stuff usually isn’t visible on a MRI, but mine was. (In fact, he asked if he could reuse the images for educational purposes because he’d never seen a visible split in a PCL like that. Lucky me.)
The PCL tear and hyperextension allowed the synovial tissue that surrounds the knee to get pinched in the joint. The pinched tissue began to scar and inflame in a vicious cycle of increased scarring, inflammation, and sensitivity. The torn meniscus also had a loose flap that would sometimes get folded back on itself and was also quite painful. I tried to live with it for a while, treating it with ice and cortizone shots, but after it flared up about 40 miles into my first Lotoja back in 2007, I had had enough.
In October 2007 I had surgery wherein the scarred synovial tissue was removed and the torn meniscus was trimmed back so it was smooth. Nothing was done for the PCL for aforementioned reasons.
Since then skiing and riding bikes has been no problem. Hiking uphill is no problem since the risk of hyperextension is negligible. I’m always a bit nervous going down, though. But if I ski down, keeping my knees bent, there’s almost nothing to worry about.
So why am I bringing this up now? Well I had plans to race tonight and tomorrow. And to Ride Around the White Rim in One Day on Saturday. But last night UtRider and I took one of our clients hiking in Corner Canyon after work, and while stepping downhill onto one of the footbridges, I hyperextended my knee. It didn’t hurt much when it happened, but by the time I went to bed it was swollen to the point that it looked like someone had sliced a lemon in half and shoved it under the skin on the outside of my knee.
We’ll see how soon the holy trinity of ice, Aleve, and compression can get me back on the bike.