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ACL Injury: Do I Need Surgery?

Following an ACL injury, a decent amount of people have asked “is surgery after an ACL tear necessary”? Have you ever wondered that to yourself and seek some answers?

It is a very loaded question because there are a lot of factors that go into the answer. To keep it very simplified, sometimes you may not need surgery for your ACL tear! Before we go into why, let’s go over the ACL and its function.

What is the ACL?

ACL is the anterior cruciate ligament (ACL) that helps provide stability in the knee. Moreover, it protects that knee from going into excessive hyperextension and secondarily from caving in (valgus stress). It is torn through 2 primary mechanisms: contact and non-contact. In non-contact injuries, the ACL is usually the most vulnerable when the foot is planted, slight knee flexion, and pivot or rotational force placed inward on the knee. Check out this video in which we talk more about how ACL injuries occur

What Happens After You Tear Your ACL?

When you tear your ACL, there is usually an audible “pop”; however, sometimes it may not be heard because it happens so fast or game/audience noises muffles it. Furthermore, you may not experience any pain because when full tears happen, there are no nerve endings and nociceptors to send signals to your brain. When there is pain with a full ACL rupture, there are other structures involved with the injury that will send pain signals to your brain, such as a torn meniscus, over stretched muscles or surrounding ligaments, impact on bones, cartilage damage, etc.. 

In the first two days immediately after injury, the goal is to decrease your swelling and pain as much as possible. After the initial inflammatory stage, then you need to start rehabbing your knee and determine if you need surgery or not.

The most important step, regardless of whether you will have surgery or not, is to start rehabbing your knee. We have seen it countless times in the clinic, where athletes go into surgery not using their knee for up to 8 weeks! We tell people the less swelling, the more ROM, better muscle control, and the stronger you are prior to surgery, the better the outcomes you’ll have.

How Do I Know If I Need Surgery?

One of the main ways to figure out if you truly need surgery is to determine if you have any signs of instability. 

What are signs of instability you may ask? When we talk about having true instability, it means that your knee gives away when you are doing certain activities. These activities include walking, sitting-to-standing, going up and down stairs, running, and eventually higher level activities. The reason your knee gives way or feels unstable is that the ACL provides stability in the knee, and without it you may experience these moments of instability. 

Here’s where it can get a little confusing and kind of a gray area. Early in your rehab following the ACL tear, your leg muscles, specifically your quadriceps, aren’t going to be firing well because of trauma of the injury and swelling. As a result, you may experience these symptoms of instability and think you need to have surgery ASAP. 

Therefore, we encourage people to perform p/rehab right after ACL tear. During this p/rehab phase, you will not only improve your post-surgical outcomes, you can determine if you are a “coper” or “non-coper”.


  • Your Knee Gave Out Only 1 time or less
  • >80% on Single Leg Hop Test: 6-Meter Timed Hop Test
  • >80% on a Subjective Questionnaire: KOOS-ADL 
  • >60% of Global Knee Rating Scale


  • Knee Has Given Out Multiple Times
  • Poor Knee Range of Motion
  • Persistent Pain & Swelling
  • Poor Tolerance to Daily Activities
  • Low Quality of Overall Function

With the knowledge of “copers” vs. “non-copers”, we have to educate you on what research states about categorizing individuals in one or the other. Research has shown that you can move from one category to another and vice versa. For example, after your initial injury you can be a non-coper, but after doing some p/rehab you’ve been categorized as a coper now. However, going from a coper to a non-coper is also a possibility. For example, early on in her p/rehab you are feeling stable and your function vastly improved. However, when you try higher level activities, such as running, hopping or cutting, you may notice a regression in your stability. Therefore, we recommend you work with a physical therapist to help guide you through your journey!

Another key factor in determining whether or not you should have ACL surgery is your activity level goals. If you do have signs of instability, but do not plan on going back to high level competitive sport then surgery may not be recommended.

What Are My Risk of Developing Knee Arthritis?

That is a great question because there is research that has shown interesting results on knee arthritic development. We do know that risk factors of developing arthritis include having a significant knee injury, such as a torn ACL, and a history of playing cutting/pivoting sports. For example, research has shown that regardless if you have surgery or not, your arthritis develops the same because of the trauma and instability the injury causes. You are only at more risk in comparison to an individual that didn’t have a significant knee injury. With that being said research does demonstrate that with every surgical procedure you have, the risk for arthritis increases. 

However, increased risk for arthritis does not necessarily correlate with having knee replacement surgery or having painful symptoms. As we all know, as anyone gets older, the more likely you are to develop arthritis because that is a normal part of aging and bodily changes. Furthermore, most of the time arthritis does not equate to symptoms; therefore we encourage athletes to not heavily factor in risk of early arthritis. The key factors in reducing your risk of developing arthritis are keeping your BMI/weight at a normal level, improving muscle flexibility, and maintaining/gaining as much strength and stability.


In conclusion, the point of this blog article is to gain a different perspective and make the most informed decision for yourself. If you tore your ACL, having surgery may not be the best choice for you. You must take into account your symptoms, your activity level goals, and the development of your stability over time. If you try p/rehab and you have signs of instability and meet the categorization of a “non-coper, then ACL surgery is likely recommended. However, if you don’t have any signs of instability and the goal isn’t to return to high level, competitive sports then surgery may not be the answer for you.


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. Monk, A. Paul, et al. “Surgical versus conservative interventions for treating anterior cruciate ligament injuries.” The Cochrane Library (2016). Thoma LM, Grindem H, Logerstedt D, Axe M, Engebretsen L, Risberg MA, Snyder-Mackler L. Coper Classification Early After Anterior Cruciate Ligament Rupture Changes With Progressive Neuromuscular and Strength Training and Is Associated With 2-Year Success: The Delaware-Oslo ACL Cohort Study. Am J Sports Med. 2019 Mar;47(4):807-814. doi: 10.1177/0363546519825500. Epub 2019 Feb 21. PMID: 30790527; PMCID: PMC6546284.

The Basketball Doctors - Gabriel Ignacio Physical Therapist

Dr. Gabriel Ignacio PT, DPT, OCS, TPI

The Basketball Doctors - Marco Lopez Physical Therapist

Dr. Marco Lopez PT, DPT, CSCS

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