ACL Injury: To Undergo Reconstruction or Not? What Research Says

ACL injury has been a highly researched and discussed topic for years in the rehab world. Studies have looked at predisposing factors, rehabilitation protocols, length of time before return to sport, and much more. As a female who spent countless hours on the soccer field, I have a special interest in this topic. Most people know that ACL injuries affect more female athletes than males, and sports involving cutting and pivoting have the highest injury rates to the ACL. This post is most relevant to those individuals who have already sustained an ACL injury. I will outline the current evidence and my arguments for making a very individual decision on whether to undergo ACL reconstruction after injury. 

Before I dive in, I will preface all this information with saying that if I had torn my ACL as a youth athlete, in the midst of my soccer career, my decision regarding surgery would likely be very different from my present life as a 30-something year old female. At that point, I would not have wanted to waste any time, would need a high level of knee stability to continue in the demands of my sport, and would not have the knowledge and patience that I have now to try another route. In my current life, continuing to be active in straighter plane activities, potentially bracing the knee for lateral activities, and building up strength around the knee would likely suffice for my lifestyle.

The first topic that I discuss with a client who has undergone ACL rupture is that she should be in physiotherapy regardless of her upcoming decision regarding surgery. For clients considering surgery, the literature shows better post-operative outcomes when rehabilitation is done before surgery as well as after (8). The stronger your leg is before surgery, the stronger it will be afterward. Pre-operative goals include swelling control, restoring normal knee range of motion and gait pattern, and improving strength and coordination. These are ALSO the goals for someone who opts to try conservative rehabilitation. Best plan of action is starting early, and maximizing your potential with any route of action. 

Once the individual understands that a rehabilitation program is essential to restoring knee function, we discuss their sport and goals for future activity level. A recent study (4) classifies sport and work requirements into Activity Levels 1-4. There is no clear answer as to which Levels require surgery, however we know that individuals performing Level I activities have the most need for an ACL, followed by Level II. Level III & IV activities place little to no stress on rotary/lateral movements of the knee. It is important to consider the future demands on the knee. If rotational and pivoting movements are not a goal, this warrants discussion about whether surgery is truly necessary. 

Many people have already made up their mind that having surgery will be the easiest  fix for this injury. The facts regarding ACL surgery should cause reconsideration in many cases. Clients will continue to have issues with knee stability and function if rehabilitation is not given 100% effort and if it is not continued for at least 9 months (at a minimum). If someone cannot commit to a program of that length, there should be serious consideration if this is the right time to do surgery.  Surgical success is never guaranteed. While ACL reconstruction has high success rates, the following should be considered: two years after ACLR, 22% of patients report poorer knee function than the general population and 24% of patients will have sustained knee reinjuries (3).

Individuals who opt to try conservative rehabilitation often do not take rehab as seriously as they would if they had a surgery. There is something about “surgery” that kicks people into gear and prompts them to make sure the surgery goes well. Therefore, we might not know the true potential of conservative rehabilitation in the appropriate population. 

A 2018 multi-continent cohort study looked at 300 individuals with ACL rupture. They identified variables that increase confidence in conservative rehabilitation: female gender, older in age, good knee function (as measured by single-leg hip tests and patient-reported outcome measures). This study followed up with individuals 2 years after the initial injury (3). A 2016 Cochrane systematic review compared conservative management after ACL tear to ACL reconstruction. The review concluded that ACLR did not show superior outcomes compared to conservative management up to five years after the initial injury. The review included active individuals, but the rehabilitation protocols varied amongst studies (7). 

Another major consideration for conservative rehabilitation vs. surgery is rates of osteoarthritis (OA). ACL reconstruction is often recommended to reduce future rates of OA by means of improving rotational stability, thereby reducing injury to the menisci. However, studies have not shown a difference in OA rates between the two groups, and some studies suggest OA rates may be lower in conservative treatment groups. A Swiss Study compared knee osteoarthritis at a mean of 11.4 years post-intervention. The study included two groups, one reconstruction and one conservative treatment, each having 47 individuals. They used the IKDC (International Knee Documentation Committee) Score to measure level of perceived function, and there were significantly higher postoperative scores for the resconstructive group. However, 42% of patients in reconstructive group developed osteoarthritis vs. 25% in the conservative treatment group. All knees included in the group had no other ligament or meniscus damage at the time of ACL injury (5). 

As the medical world advances rapidly, I would also consider how advice regarding knee surgery may change in the next few years. There are currently stem cell procedures being performed in which the client’s actual ACL tissue is regenerating, completely avoiding the negative results of surgery. We may see the above argument change entirely, if procedures like this are validated in the literature and make their way up to Canada. 

Take Home Points:

  • If you are not an individual who plans to immediately return to cutting and pivoting sports, why not give conservative rehabilitation your 100% best effort to see how functional and strong you can get your knee? You will not lose anything by delaying a potential future surgery (2), you will be improving your post-surgical outcomes if you do have surgery, and finally if you avoid surgery you may be protecting yourself against higher rates of knee osteoarthritis down the line. 
  • Start rehabilitation as soon as possible with a professional who understands the demands of your lifestyle and/or sport, and who works at a facility that can administer an exercise-based physiotherapy program to ensure you are pushed to your absolute highest potential.


  1. Can you walk is ACL is torn? It depends but yes you can in most cases. As long you move in straight lines and only the ACL is affected, you can walk, go up and down stairs and possibly jog.
  2. How long does it take to recover from an ACL tear? Recovery will take 6-12 months depending on your goals post ACL teal Returning to sports after an ACL tear can take up to 12 months.
  3. Can you live without an ACL? Many people live active lifestyles without an ACL. With proper rehabilitation and strengthening, you can return to every day activities, running, hiking, biking and many other activities.


  1. Eitzen I, Moksnes H, Snyder-Mackler L, Risberg MA. A progressive 5-week exercise therapy program leads to significant improvement in knee function early after anterior cruciate ligament injury. J Orthop Sports Phys Ther. 2010 Nov; 40(11):705-21.
  1. Frobell, Richard B., et al. “Treatment for acute anterior cruciate ligament tear: five year outcome of randomised trial.” Bmj 346 (2013): f232.
  1. Grindem H, Wellsandt E, Failla M, Snyder-Mackler L, Risberg MA. Anterior Cruciate Ligament Injury-Who Succeeds Without Reconstructive Surgery? The Delaware-Oslo ACL Cohort Study.  Orthop J Sports Med. 2018 May 23;6(5):2325967118774255. 
  1. Hefti F, Muller W, Jakob RP, Staubli HU. Evaluation of knee ligament injuries with the IKDC form. Knee Surg Sports Traumatol Arthrosc. 1993;1:226–234.
  1. Kessler MA, Behrend H, Rukavina A, et al. Function and osteoarthritis after ACL rupture: 12-year follow-up results after nonoperative vs. operative treatment. #SS-08. Presented at the Arthroscopy Association of North America 25th Annual Meeting. May 18-21, 2006. Hollywood, Florida, U.S.A.
  1. Moksnes, Håvard, Lynn Snyder-Mackler, and May Arna Risberg. “Individuals with an anterior cruciate ligament-deficient knee classified as noncopers may be candidates for nonsurgical rehabilitation.” journal of orthopaedic & sports physical therapy 38.10 (2008): 586-595.
  1. Monk APaul, Davies LJ, Hopewell S, Harris K, Beard DJ, Price AJ. Surgical versus conservative interventions for treating anterior cruciate ligament injuries. Cochrane Database of Systematic Reviews 2016, Issue 4. Art. No.: CD011166. DOI: 10.1002/14651858.CD011166.
  1. Shaarani SR, O’Hare C, Quinn A, Moyna N, Moran R, O’Byrne JM. Effect of prehabilitation on the outcome of anterior cruciate ligament reconstruction.  Am J Sports Med. 2013 Sep;41(9):2117-27.
  1. van Yperen DT, Reijman M, van Es EM, Bierma-Zeinstra SMA, Meuffels DE. Twenty-Year Follow-up Study Comparing Operative Versus Nonoperative Treatment of Anterior Cruciate Ligament Ruptures in High-Level Athletes. Am J Sports Med. 2018 Apr;46(5):1129-1136. doi: 10.1177/0363546517751683. Epub 2018 Feb 13.

Have questions about a particular injury or topic? Fill out our contact form or chat with us using the chat box in the bottom right hand corner of your screen.

Share this: