On Sept. 10, 2014 I took a spill on my 36″ unicycle. It was freakish dumb luck (more on this later), and it did a real number on my knee–complete tear of ACL, sheared cartilage, and meniscus tear.
Whilst lying in bed doing some research and finally learning some knee anatomy, I learned that just last year a new ligament in the knee was discovered. Are you a little skeptical? I was. I couldn’t believe that as late as 2013, with all the diagnostic equipment we have–x-rays, MRIs, etc.–that there could still be something we did not know about the human knee. But, indeed two Belgian doctors confirmed what a French doctor had suspected some 130 years earlier.
The four main previously known ligaments of the knee are the lateral collateral ligament (LCL) on the outside of your knee, the medial collateral ligament (MCL) on the inside of our knee, the posterior cruciate ligament (PCL) in the center back, and the infamous anterior cruciate ligament (ACL) which crosses the PCL in the middle of the knee. And now there is a fifth: the antereolateral ligament (ALL) — it runs near the LCL and helps the ACL stabilize the knee. In fact, it is now suspected that those ACL repairs that don’t completely address knee stabilization may be a result of an undetected (and thus, unrepaired) torn ALL. (See article.)
So, the next question is: How has this discovery changed the treatment of knee injuries? At least, that was my next question given that I was reading about this while lying in bed with a painful unstable left knee. Well, an English doctor, Dr. Aidan Wilson, started working with the doctors that discovered the ALL and developed a surgery to fix both the ALL and the ACL at the same time. He even put a video of the surgery online (not for the squeamish).
At 1:47 in the video you will see where Dr. WIlson does a “pivot shift” test, and concludes based on how much the knee is giving way, that the ALL is torn. It made me wonder how precise is that test, and what other ways are there to detect a torn ALL.
So, when I met with my sports medicine doctor with my MRI results, I asked him if he can see the ALL. (Note my images were taken with a 1.5 tesla MRI). He said they could not–which didn’t surprise me, otherwise, the ALL would have been discovered long ago.
When I raised the issue of potential ALL damage, my doctor was polite, but still a bit dismissive. He said that first of all, doctors are always trying to make a name for themselves by coming up with a new procedure. And second, that it was a “ceiling function”, i.e., they have 98% success rate with ACL reconstruction, so going for 99% is not justified.
To the first point, I think that addressing the fact that there is a ligament in play that we did not previously know about, is not a difference in degree of some nuanced procedure, but rather a difference in kind. Even the most humble of doctors/humans don’t like to admit that they may be missing something in their daily practice.
As to the relative success rate of ACL surgeries, I don’t know what the numbers are. The surgery is not perfect; and at a minimum, I would want to know if my ALL is torn. (Given how unstable my knee is, the way in which the injury occurred, and my bad luck, I suspect that my ALL may be torn.)
Obviously, it was take some time for the discovery and new surgical methods to propagate out (and get treatment codes assigned to them). Even if the conclusion is that most torn ALLs should not be surgically repaired, the baseline question is: How can a torn ALL be detected?