Healing of acute ACL tear on MRI following non-surgical bracing protocol [pdf] | Hacker News Reader

Healing of acute ACL tear on MRI following non-surgical bracing protocol [pdf]

bjsm.bmj.com

105 pointstrogdor56 comments

The highlights, as I understand them:

-In November 2022, the principal investigator on this study published the results of a different study which found MRI evidence of ACL healing in 30% of patients who were randomized to physical therapy with optional delayed ACL reconstruction. [0]

-When an ACL is fully torn, the gap between the ruptured ends inhibits healing. Since the ruptured ends are in closest proximity at 90°-135° of knee flexion, this study investigated whether bracing the knee at 90° would facilitate ACL healing.

-This study lasted five years and involved 80 patients. All participants had full-thickness ACL tears (complete discontinuity of the ACL on MRI). The protocol involved four weeks of bracing the knee at 90°, followed by progressive brace adjustments that slowly increased knee range of motion. The brace was removed at 12 weeks.

-At three months, 90% of patients showed evidence of ACL healing on MRI. Moreover, MRI evidence of ACL healing was associated with better outcomes.

This is monumental.

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9872245/

So 90% of patients who wore the knee brace instead of getting a surgery healed properly?

There is no definition of “healed properly” in relation to ACLs, in part because it is (hopefully soon was) commonly believed that a ruptured ACL has limited healing capacity.

Patients were eligible for this study if they presented within one month of acute ACL rupture confirmed on MRI. The MRI had to show full discontinuity of ACL fibers.

“After management with the Cross Bracing Protocol, 72 out of 80 (90%) participants with complete discontinuity of the ACL at baseline had signs of ACL healing (ACL continuity) on 3-month MRI.”

The paper explains the rating scale they used to evaluate ACL healing on MRI.

Thanks for the closer reading!

They didn't heal, a full rupture is a full rupture.

They showed that for younger patients they can, through physical therapy, replace the ACL stability function with overcompensated proprioception and musculature.

I wonder what the outcome of this would be as patients get older and start to lose muscle mass.

I had a tear sometime in the 90s, and then not surgery until the 2000s, the good old cut your kneecap in half kind.

The doctor I saw once a year prior seemed to imply this. He implored me to do specific weight exercises, and claimed if I did it right 'you wont even need that surgery.' So it must have been at least a working theory for a while?

They did heal.

> After management with the Cross Bracing Protocol (CBP), 72 out of 80 (90%) participants with complete discontinuity of the ACL at baseline had signs of ACL healing (ACL continuity) on 3-month MRI.

Seems pretty definitive as healing to me.

Huge for reducing unnecessary surgical procedures. In what situations would surgery still be required?

Edit: would imaging be able to delineate?

Having 10% not heal isn’t great… Since surgery is much more reliable I see it still being standard of care.

How reliable is surgery?

Surgery is invasive and recovery is rough. Not sure what the data says but I would’ve liked this option

Standard of care could be bracing followed by surgery if it's not taking.

No, 90% is massive if true. Speaking from experience the surgery is an absolutely brutal experience. Even though my graft was successful, if I had my time over I'm very much not sure I would make the same choice. I would at least explore other avenues. Many people do fine without an ACL. In my case my cartilage went from, in my surgeons words, pristine (post injury and before surgery), to tricompartmental osteoarthritis 18 months after the operation.

Surgery involves taking strength from another ligament (and attached muscle group) and a long and painful recovery process.

Not to mention costs tens of thousands of dollars.

Surgery is expensive and ACL tears are not "critical." Showstopper for basketball, soccer, etc, but not for walking, squatting, running, etc

(I've had a re-torn ACL for ~8 months now. I'll get surgery eventually.)

You have to remember that surgery comes with very significant secondary risks (MRSA infection, etc, etc).

Last I heard, Dr. Filbay is working on a decision aid for patients.

Here’s my guess as to what it’ll suggest:

First, do the bracing protocol. Then do intensive physical therapy. If, after both of the above, you have functional instability that is adversely impacting your quality of life, consider surgery. Otherwise, don’t.

>Would imaging be able to delineate?

Seems like a strong maybe. Check out “Implications of findings” on page 7 of the paper.

The only thing that's tough about this approach is you work hard at physical therapy but still you end up being the percentage that still needs surgery. Then once you get surgery you have to start all over again. I delayed ACLR personally because of a multi ligament tear and the toughest part was the burnout of starting back up again after surgery.

I had a so-called terrible triad (MCL/ACL/meniscus) so in addition to ACL reconstruction, my surgery included meniscus debridement. I unequivocally needed surgery (it was a contact injury playing sports), and thanks to surgery made a 100% recovery (albeit with a ton of PT!). That said, if surgery can be avoided in less traumatic tears (e.g., "stop-and-pop" ACL tears) so much the better!

Just had my ACL reconstructed out of my quad a few weeks ago, and the thought of just being in a brace rather than harvesting my quad tendon sounds lovely!

The patients were 26+-10 years, so possibly less applicable later in life, but still fantastic

Monumental especially for football players who are usually never the same after an ACL surgery which often leads to the shortening of the tendon, limiting its efficacy and putting it at a greater strain which leads to an inevitable relapse.

I’d think for athletes a 10% chance of failure would make it a total non starter.

This is an odd take. From what I understand from the article it’s a 90% chance of healing, after which you can still get surgery — which doesn’t heal but restores some functionality by grafting from another tendon. I’d imagine athletes would be particularly interested in trying this new treatment prior to considering surgery.

My assumption was that the original comment was about professional athletes. For them any delay to returning is generally considered disastrous, and reconstruction success rates for them are near 100%, their recovery timelines are extremely quick, and doing PT all day isn’t really that different from what they normally do. Recovered performance is also incredibly good these days in most cases.

This conservative approach could become the default for most everyone else, but for professional athletes 90% success is not going to fly.

If the original comment was about casual athletes then none of this applies.

Sort of related, I suffered a tib-fib fracture in April 2006. It was splinted at E.R. and I received crutches. I visited PCP to follow up and he questioned whether it was displaced. At the time, I did not think much of his theory and said no more about it. When I finally got to an orthopedic clinic, they put a whole-leg cast on, with significant struggle, and the first thing I noticed was that my foot was sticking out at a very noticeable angle. I am fairly confident that this is the displacement my PCP mentioned.

9 months later I had been through several casts and an utter quack treatment of "electronic pulse bone stimulator" just to squeeze as much insurance money as possible out of Medicaid. My surgeon announced an atrophic non-union and said that surgical fixation was the only way forward, which I accepted and everything turned out fine.

Of course nobody will listen or talk about the displacement which caused the non-union in the first place, because that would be tantamount to orthopedic malpractice, and I am still embittered when I think back on what could have been different, but at least it had no lasting detrimental effect on my mobility.

More people need to understand that in most cases, ACL surgeries are unnecessary. The most common experience people have with them is during high school athletics, and yes - returning to sport is indeed an influencing factor in the decision to perform surgery. But how many of these students would go on to be pros?

There's a vast difference between "pro" and "beer league" when it comes to being an athlete, and an ACL repair is only needed for the former.

People sometimes refer to ACL reconstruction surgery as “ACL repair.” Unfortunately, we can’t surgically repair a torn ACL.

ACL reconstruction surgery involves drilling bone tunnels into the tibia and femur, removing the torn ACL fibers, harvesting a tendon from your body (or from a cadaver), and affixing that tendon to your tibia and femur in place of what was previously your ACL.

Yes, thanks for the detail, if we're being technical.

You seem to be knowledgeable in the field, I'm curious if you have any broader disagreement with the point of my original comment?

If you ever want to ski or play soccer again, even just casually, you need an ACL.

I had ACLR and despite a horrific recovery process from the surgery I'm still glad I got it, in my mid-30s, as a software engineer.

As I understand it the tendon forms a matrix that allows a ligament to regrow along it. At around 3 months the tendon graft dies off and the ligament tissue continues to grow.

90° bracing means a kneeling skate or rest.

Non use of the leg will mean significant loss of muscle tone. I had a meniscus tear and it was 8+ months of continual physio and exercise to get back to usably "normal" and I continue to do targeted exercises. My physio can still see clear differences in the leg sizes.

Probably unavoidable with ACL tear anyway.

Electrical stimulation might help prevent atrophy while waiting to see if the bracing works.

Or after some window, maybe exercise of the muscles within the allowed loading and movement range.

That’s probably going to differ between individuals quite a bit. I had a pretty bad broken leg, and could barely use it at all for nearly 4 months. There was a noticeable size difference after the bone had healed, but normal function wasn’t really impaired, and it was only a couple months more until I was training like normal again.

ACL surgery is much worse

For muscle loss? Doubt it. SIL was doing exercises the day after her surgery. With a 90 degree cast, no exercise can be done on the many of the muscles.

I lost my medialis quad activation completely for 6 weeks after ACLR surgery. It took 6 months of PT to get my patella to track straight afterwards, and it still isn't quite right.

After being in a cast when I was 13 for 6 months, I lost quad size that I never regained, even after 40 years of trying. You can easily see the difference with the eye.

This study details the protocol used, which has patients brace-free and fully weight-bearing at 15 weeks. There are exercises to minimize muscle wasting but yeah, some is unavoidable.

I read these articles and all I can think is...

If some surgeons hadn't insisted healing was impossible and surgery the only option when would we have realised healing is possible? How many would have skipped the graft and simply switched sports?

Oof, bracing your leg that long… i hyperextended a knee and ‘miraculously’ didn’t tear anything… but then my knee didn’t fit together anymore tightly like it should. It was a painful recovery with months in various braces and a lot of pt. Over a decade later I’m barely on par with muscle mass between the two legs.

I wonder if history is any guide here. With how prone knees are to injury, I wonder what the historical outcome for those injured by ACL tears was. The gut reaction is “death,” and I’m sure that happened a lot, but I’m sure there were some who survived. How did they fare long-term?

They'd fare just fine. You don't need your ACL. It helps to keep your knee from giving out during certain sudden movements, but a lifetime of conditioning would prevent against that. High level football players have played seasons without an ACL, for example.

They do so wearing a brace and trading chances for massive damage to the knee for finish-out out the season and getting paid. We had someone in college football do that because it was the last 2 weeks of his senior season. He suffered cartilage damage from it and wouldn't do it again.

I was thinking about players like Hines Ward, who played his entire career without an ACL.

Most players will get it repaired because at that level any small percentage performance improvement (or risk reduction) is worth it. But the body can compensate for the lack of an ACL through strengthening the surrounding musculature.

Interesting, didn't know about that. However it sounds like maybe he never had one or it snapped early on and he grew up without one, which is different than being at the height of your game and losing it. My friends who snapped ACLs in college or highschool never felt safe on those knees again and it limited what they were willing to do move wise.

There is significant evidence that Neanderthals lived in communities which supported each other, even when they were wounded. Most notably, Shanidar 1 [1] was found with hearing loss, a severed (yet healed!) arm, and broken legs, indicating that someone else must have cared for him for some time.

[1]: https://en.wikipedia.org/wiki/Shanidar_Cave#Shanidar_1

>...The sharp point caused by a distal fracture of the individual's right humerus points towards this theory of amputation. If the arm was amputated, this demonstrates one of the earliest signs of surgery on a living individual.

Deliberate amputation at 45,000 to 60,000 BCE! I suppose they could have immediately cauterized the wound, but it is incredible that someone would survive the procedure without succumbing to sepsis or blood loss. Would they have even considered a tourniquet?

People without an ACL would develop a "trick knee" and get arthritis faster, that's it. It increases your chance of screwing up your miniscus more, but it's not at all a death sentence.

This entire thread makes me very glad I lost interest in sports pretty early in my teens.

I'm glad they have treatments, but I'd rather prevent it in the first place.

This is good for Radiologists and not so good for orthopedic surgeons.

How does this help a radiologist? They would be taking pictures of the recovery either way no?

Could make an argument that there would be significantly more follow-up scans to see if healing is progressing on schedule or if surgery is appropriate.

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