Long Term Effects of ACL Reconstruction Surgery: The Procedure Destroys the Normal Wiring of the Knee

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We tend to take for granted that our bodies are finely tuned machines and complex neural circuitry allows them to do the amazing things we’re designed to do. A 2011 study shows that these essential circuits are first messed up by an ACL injury, and then by the long-term effects of ACL reconstruction surgery.
long term effects of ACL reconstruction

What We Know About the Long Term Effects of ACL Reconstruction Surgery to Date

Before I get into the ACL surgery side effects, let’s review what the ACL is. The anterior cruciate ligament (ACL) is one of four main ligaments that provide stability and precise motion to the knee. The ACL runs through the middle of the knee and attaches the bottom of the femur (the long upper-leg bone) to the top of the tibia (the larger lower-leg bone). The ACL is responsible for controlling front-back motion and rotation in the tibia, which stabilizes the knee.

The ACL can become torn or damaged, and these injuries are quite common in athletes, such as soccer and football players, and other active people who place intense forces on their knees. When the ACL is injured, this causes excess rotation and motion in the tibia and makes the knee unstable as shown in this brief video.

The conventional go-to treatment for a torn ACL is surgery to reconstruct the ligament. If you’ve followed this blog for any length of time, you know that ACL surgery side effects are numerous. We know, for example, the reconstructed knee never functions like it did originally because the mechanics of the knee are permanently altered following ACL surgery. Why? The ACL graft, the new ligament, is attached at a steeper angle, which can not only cause rotational instability in the knee but can also disrupt the normal sense of proper position.

Additional long-term effects of ACL reconstruction surgery include the fact that despite popular belief, knee arthritis is not prevented by undergoing ACL surgery, and, in fact, the operation may cause arthritis to set in sooner. Also either knee, the knee operated on or the opposite knee, has a six times greater chance of tearing following ACL surgery in active patients who return to sports after the surgery.

And just when we think we’ve encountered it all, another study showing still more long-term effects of ACL reconstruction surgery side pops onto our radar screen, like the one below.

Learn more about the treatment of ACL without surgery.

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How Does the Wiring of the Body Interact with a Ligament like the ACL?

The severe failings of modern orthopedic surgery are twofold: focusing on one body part and only considering its mechanics. I’ve blogged extensively on the fact that there is no such thing as a “knee.” There is a machine called the “spine-leg” that has a part that’s specialized that we could call “the knee.” So by making everyone think that the knee acts in isolation of its other parts, we’re doing a huge disservice to reality as the knee works in concert with the spine, hip, and ankle parts of that machine. The second major issue is that modern orthopedic surgery completely forgets about the wiring of the body. What do I mean?

We see all about us these days ever-sophisticated electromechanical devices. One that you may have seen is the complex of gears, joints, and levers that make up the machinery for stabilizing a camera. You can find these devices to stabilize your phone or a GoPro or on every mid-priced drone being sold with a camera. This serves to make the picture ultra-steady despite movement. These devices have been around for a long time, but they cost tens of thousands of dollars and are used only by professional movie photographers and your local news station filming from its chopper cam. Now they’re miniaturized and mass produced.

Let’s say this apparatus gets broken in some way so that it no longer works correctly to stabilize the camera. We know that there are two major categories that we need to consider to see why it’s not working: mechanical and electrical. The mechanical part is easy enough, as all we need to do is to inspect the gears, joints, and levers. However, if there’s nothing wrong there, we also know that there could be problems in the wiring or complicated circuitry that tells the device which position the camera is in relative to the ground and how to move to counteract that movement. However, for modern orthopedic surgery, it’s all about inspecting the gears, joints, and levers of the body, and there is no focus on the wiring and circuitry.

The paper I’m reviewing this morning concerns the wires and circuitry of the ACL. While the ligament has mechanical functions, like stabilizing two bones that make up the knee, it also has a large number of position sensors that provide information to the muscles of the leg on how to fire through a bit of wiring call the “gamma loop.” Think of this as like the sensors in the joints of the camera stabilization system that then tell the motors to adjust the position of the camera. Said another way, the sensors in the ACL tell the quadriceps muscle (the big one in the thigh) how much to fire and when. So a busted gamma loop means that the ACL isn’t coordinating muscle firing that in turn protects the knee by adjusting the overall joint position.

The Research on the ACL and the Gamma Loop

This 2011 study used a number of different modalities to measure the activity of the gamma loop in patients without an ACL tear, with an ACL tear, and with an ACL reconstruction. The researchers found that, not surprisingly, just tearing your ACL impacts this significant bit of neural wiring. This makes sense as the ACL has tiny position sensors that could be injured in the same trauma that tore the ligament. Also, loose ACL fibers won’t pull on the intact sensors the same way. Also, not surprisingly, they found even worse function of the gamma loop when the ACL was surgically reconstructed. Why? There is no way to hook up the thousands of microscopic position sensors in the tendon graft that serves as the new ACL so that the body can react to pulling on the artificial ligament.

No matter how you cut it, ACL surgery is not a replacement of the original equipment but a 1980s attempt at replacing what was lost. What you get doesn’t function like what was there, which is one of the big reasons we push suitable ACL tear candidates toward ligament healing using our proprietary same-day stem cell injection. The goal is to keep the mechanical function and wiring as intact as possible.

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17 thoughts on “Long Term Effects of ACL Reconstruction Surgery: The Procedure Destroys the Normal Wiring of the Knee

  1. R. Bradley Reeves, M.D.

    Are there any level 1 or 2 studies comparing outcomes of ACLR vs stem cell treatments? could you supply those to me please.

    1. Chris Centeno Post author

      Brad, there are no such studies yet. However, we also have limited level 1 evidence for ACLR. We have a larger imaging case series that’s be submitted now and an ongoing RCT.

  2. Dom Costabile DO MS FAAFP RMSK

    Thanks for sharing, I love your blogs as they improve my thinking and understanding of the many vignettes you share. I recently became aware that the origin of the word diagnosis stems from the root ” a way of seeing”. Far too often in the vast expanse of expanding medical information we stop at the term or ICD code, and stop thinking about antecedent factors, triggering events and modifying factors. Especially after a procedure or remedy. Our ability to repair and regenerate is a miracle all living organisms possess. We know so little of this marvel or nutrition which fuels the fundamental of this life process. Our name ,blame and attempt to tame ( pharmacutically or procedurally) tool box and mind set is so mideval in the context of 2016 bio molecular and biophysical knowledge. Thanks for helping me and you readers see anew and further upstream. Dom Costabile

  3. Natalie

    I was wondering what age this typically happens to, also if you could treat this without surgery.

    1. Regenexx Team

      Hi Natalie,
      It’s not something that happens at a particular age, it’s more about the individual surgery. Please see: https://regenexx.com/blog/acl-surgery-failure/ and https://regenexx.com/blog/new-acl-stem-cell-infographic/ Please let us know if you would like to set up an exam.

  4. Linda Reynolds

    I had major reconstructive surgery on my left knee in 1975 when I was 20. I am a female. A straight horizontal cut across my entire knee. I had torn the ligaments and collapsed playing basketball and was told I had subluxating patella in both knees. I did not let them operate the other knee as they wanted to because the left one has never been the same. 45 years later the knee is a mess and I have also re-injured it. Two ortho doctors said I needed a knee replacement. A third said I am not a candidate due to the damage the reconstructive surgery did. I am deeply discouraged; now the pain is not only in my knee but at times involves my shin, calf, ankle, etc. Would this stem cell therapy help an injury/damage like mine?

    1. Regenexx Team

      Hi Linda,
      We won’t know until we can do both a Candidacy Review and an exam. Do you have a recent MRI?

  5. Tommy

    If only the Stem Cell therapy is available worldwide =( I have a high Grade Partial tear and my surgeons wants to reconstruct my entire ACL 😢

    1. Regenexx Team

      Hi Tommy,
      We have a Regenexx provider in Taiwan, Province of China: https://regenexx.com/providers/chun-chuan-clinic/

  6. Kate McDonald

    Does your treatment need to be done within a specific time frame of the initial injury? Also what is the cost?
    I am trying to avoid surgery.

    1. Chris Centeno, MD Post author

      Not necessarily, meaning we have treated patients up to 1-2 years after ACL tear, but usually the earlier the better. The cost depends on what needs to be done, so I would need to look at your MRI.

  7. Wendy March

    I had ACL replacement surgery in 2000. They used my hamstring as the replacement. I am extremely active and have been pleased with the results. Recently I have been experiencing discomfort/pain in my lower back and hamstring area. I feel like my hamstring is extremely tight and inflexible. I can’t seem to be able to relieve the tension. It feels like my hamstring is going to pop like a rubber band. Would you have any feedback on if there is any relation to my surgery?

    1. Chris Centeno, MD Post author

      Yes, this sounds like the hamstring graft site may be unable to handle the normal wear and tear, which is not uncommon. The best way we usually treat this is with PRP injection. There are also other causes of this type of pain.

  8. Arun Kumar Konala

    Hi I had an ACL near complete tear(based on the MRI) every ortho I see suggests to get it re constructed by surgery. I would like to know if there is anyway I can avoid this and live a normal life. I am not a sports person. I hardly walk a kilometre a day. I am 30 years old.

    1. Chris Centeno, MD Post author

      Likely, most patients like you can be helped with the ACL-repair procedure, see https://regenexx.com/blog/interventional-vs-surgical-orthopedics-stem-cell-knee-acl-repair/

  9. George M

    If the ACL is completely torn will this procedure still work or is surgery required?

    1. Regenexx Team

      Hi George,
      We treat partial, and complete, non retracted ACL tears. We’d need to see the imaging to see if you would be a Candidate: To do that, please use the Candidate here: https://regenexx.com/conditions-treated/knee/acl/ or give us a call at 855 622 7838 if you need assistance with that process.

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