Gone Again. Living ACL Deficient.

It tore. Again. I took a 7-8ft straight drop at the gym, landed on both legs, fell to my butt, and heard that pop. Two people said it looked like a perfect landing. I had nearly no pain, got up, walked out, and went home, had some swelling, but could walk, go up and down stairs, hop on the leg, and do one leg squats. But, MRI shows another clean ACL tear with no other damage.

It's been a hard week. I've run though everything that could've gone wrong and have spent hours researching more on ACLs. I trained and followed therapy to a T, gained at least 5lb of muscle in my legs, was 9 months out of surgery, and had been building up falling over the last 6 weeks. My orthopedic surgeon thinks it's likely either just a fluke, like I hit my knee just right, or it's my body not taking over the allograft (cadaver) tissue quickly.

My plan is to strengthen my legs even more over the next couple months, get a custom knee brace, and still take off on our climbing road trip. I'll consider surgery again down the road, likely using my own autograft tissue from my patellar or hamstring tendon (shudder). Luckily, this time around is completely different than the first time--at least all that training and PT paid off! I had only a single incident of instability. Seriously, I walked out of the gym and drove home.

A little on the anatomy of the knee: there's 4 main ligaments. The ACL and PCL run crossed thru the center of the knee and help with rotational stability. The LCL runs on the outside and MCL on the inside.

knee ligaments

Typically ACLs are injured with MCLs like in soccer and football, when forces come from the outside in. That's what happened in my first accident--I landed on my knee at an angle and it crunched inward. This time my knees didn't buckle at all.

There's no blood thru the knee itself so the ACL doesn't heal like the MCL or LCL. Surgery takes a tendon graft, either cadaver or your own, and drills it through your femur and tibia. My second MRI looked like this one where you can still see the bone screws:

ACL MRI

There's a lot of research and theories, but surprisingly little conclusive evidence, about the success rate for ACL surgeries. Even top players can land just right and tear their ACL:

  • ACL reconstruction is at best 95% successful and there's 200k surgeries done a year in the US. The success rate is confounded by the fact that most ACL injuries happen in athletes, who are at a much higher risk anyways for injury.
  • The precise rate of revascularization (your body taking over the tendon graft tissue and making it a ligament) is unknown, but likely around 6months for your own graft and maybe more for allograft. The graft is weaker than your own ACL until this revascularization phase is complete.
  • Normal ACLs can take ~2000N of force (~= 450lbs) to tear. It's unclear how non-contact movement like jumping or planting a foot in soccer to kick can tear the ACL without outside factors.
  • Women are at higher risk for ACL tears than men. A survey of NCAA athletes showed 2-3x more ACL injuries for women than men.
  • Theories for why women are at higher risk include hormonal changes (ligament laxity increases with estrogen), anatomy (wider hips increase the angle of the femur to knee), biomechanic (women tend to be stiffer when moving rather than absorbing impact), a smaller femoral notch (where the ACL goes through the femur), and relatively stronger quads than hamstrings (hamstrings help compensate for ACL function the most).

No use thinking about what's done. I'm concentrating on what I can do now. In the grand scheme of things, this isn't all that bad. I just want a healthy road trip and year. It still sucks being in the middle of it after a year of no climbing and hard training.

[The surgeon used the term "ACL deficient" which I actually found humorous at the time--but it's the last time I'm thinking about a deficient or "bad" knee. Both legs are great and will get stronger.]

Photo sources: 1, 2