In this blog, I am going speak about whether it is compulsory to have ACL surgery following a rupture and if it can self-heal. Also help you with the decision-making whether or not the surgery is for you. This is for education purposes only – please consult a clinician or physiotherapist to have your injury assessed first!

Short answer is no. Although surgery has contributed to many success stories, it is not the case for everyone. It is a very common knee injury that we hear about all of the time.

What does the research say?

A systematic review and meta-analysis by Ardern et al in 2014 concluded that 81% of people return to some form of sport after surgery, 65% returned to their previous level of sport, and 55% returned to competitive sport.

A different systematic review and meta-analysis by Wiggins et al in 2016 demonstrated that the rate of a second ACL injury after surgery was 15% for all patients and 21% if you were younger than 25. The group also showed if you are younger than 25 and returned to high-risk sport, there is a 23% chance of a second ACL injury. 

A study by Webster & Feller in 2016 found that the rate of second ACL injury in patients under 20 was 35%.

A more recent study by Falstrom et al in 2021 found that 42% of female soccer players who returned to soccer sustained a new ACL injury within 5 to 10 years.

Lastly, Webster et al in 2018 found that for individuals under the age of 25 who have already had a second ACL reconstruction, 27% of them will go on to have a third ACL injury.

Now these numbers will vary based on sports participation, functional readiness, and other factors, but these research papers highlight that not everyone returns to their pre-injured level. This is not meant to discourage you from having surgery if it’s the right option for you. This information should only be a point of discussion with the relevant people around you.

The intention is for it to obviously have a net benefit, but it does usually involve removing healthy tissue, such as your patellar tendon, hamstring tendon, or quadriceps tendon, to reconstruct your ACL. Now you might ask how we know that surgery works. We generally think very linearly – you get injured, you get surgery, and you feel better; therefore, surgery led to you feeling better. But that is unfortunately not always the case.

Do you need ACL reconstruction?

Researchers test for this by using something called a randomized controlled trial. An example would be to take 100 participants who got injured and randomly divide them into two groups: 50 people get surgery and 50 people get non-surgical management. Intuitively, we might think that surgery wins every time, especially for something like a torn ACL.

Out of the hundreds of randomized controlled trials in this area of research, only two have used a similar protocol. The KANON trial and the COMPARE trial randomized individuals who tore their ACL into two groups:

One group received early ACLR followed by rehabilitation, which is the usual standard of care.

The other group was assigned to rehabilitation with the option of later ACLR if needed.

What was the main relevant information we got from these 2 studies?

In the group that was assigned to rehabilitation first, 50% ended up choosing to get the surgery. The other 50% who did not get surgery had outcomes that were similar to those who had the early ACL reconstruction. This research informs us that for some individuals, non-operative management is a viable option after an ACL injury.

A study by Thorstensson et al in 2009 explored the preferences of patients in the KANON trial. One participant stated, “I wanted surgery from the beginning, but I felt persuaded to try training after randomization. I had surgery in the back of my head all the time, even when I did give training a decent go.” Another participant said, “I saw the study as a faster way to surgery, no matter what treatment arm I was randomized into.”

This shows that what you are thinking can also have a massive effect on the outcome. If you think surgery is needed and are fixed upon that decision, but have been told to exercise, you are going to unexpectedly hold yourself back because you believe that you need surgery.

Can the ACL repair itself?

Short answer is yes it can, depending on the location of tear. Studies by Fujimoto et al in 2002, Costa-Paz et al in 2012, and Ihara and Kawano in 2017 demonstrate that the ACL can spontaneously heal in some cases.

Filbay et al analysed the data from the KANON trial and concluded that “there was a high rate of ACL healing in patients managed with rehabilitation alone (58% after 5 years) and these individuals reported better patient-reported outcomes compared to the non-healed and reconstructed groups.”

How to make a decision?

Filbay and Grindem, two of the leading researchers in this field, recommend a period of rehabilitation prior to committing to surgery for most individuals with a torn ACL because pre-operative rehabilitation improves postsurgical outcomes in those who go on to have an ACL reconstruction anyway. The stronger you are going into the surgery, the better the outcome.

Based on papers by Grindem et al in 2018, Pedersen et al in 2021, and van der Graaff et al in 2022, you may be more inclined to choose non-operative management if:

You are older

Have good knee function without episodes of instability

Are feeling confident in your knee

Do not also have an injury of the medial meniscus

Have no intention of returning back to competitive sport

For example, if you’re a 38-year-old individual who wants to return to tennis and your knee has been feeling great after 3 months of rehab, you are probably better suited for non-operative management.

On the other hand, if you’re a 20-year-old college athlete who plays competitive football and your knee continues to feel unstable after 3 months of rehab, you are probably more suitable for the surgery.

As discussed earlier, your beliefs and preferences might also influence your decision. If you have your mind made up one way or the other despite this information, then that might be the appropriate choice for you.

Summary

Regardless of the decision you make, there is no right or wrong decision. An ACL tear could self-heal. Waiting a little time before the surgery is the preferred option. Make a decision with the close people around you. Do you fit the criteria – is your knee improving after initial rehab? Does it feel unstable? What are your desired goals?

Thank you for reading this. Please contact us with any questions that you may have or give us your feedback with your thoughts.