Does a Torn ACL Require Surgery?
Deciding whether to have surgery after an ACL injury? Expert physical therapists discuss.
When considering ACL surgery after an ACL injury, there are many factors to consider. Below, we discuss those factors, and more.
First, are you a Coper?
We need to determine whether you’re a “coper” to decide if you’re a good candidate for non-surgical rehab. This is done through a screening exam performed by a physical therapist.
Copers vs Noncopers Classification
Early after ACL injury, knee function is typically classified based on a screening examination. But first, there are prerequisites to even qualify for the screening exam.
Prerequisites for the screening examination:
Resolution of physical and functional impairments
Joint effusion (knee swelling)
Gait abnormalities (i.e. walking with a limp)
Range of motion (ROM) deficits (stiffness)
Ability to hop on the involved leg without pain
The screening examination:
Hop test index of 80% or more for the timed 6-meter hop test
Knee Outcome Survey Activities of Daily Living Scale (KOS-ADLS) score of 80% or greater
Global rating of knee function of 60 or greater
No more than 1 episode of giving way since the injury
Individuals passing the screening examination are classified as potential copers and those who don’t pass the screening criteria are classified as potential noncopers.
Potential copers are considered rehab candidates with the potential to return to preinjury activity levels without ACL reconstruction surgery.
Potential noncopers are usually recommended ACL reconstruction surgery, based on the assumption that they won’t successfully return to preinjury activity levels through nonoperative treatment.
One study suggests that even potential noncopers can have success with nonoperative rehab.
In this study, 70% of subjects with an ACL injury classified as potential noncopers upon initial screening exam became true copers after 1 year following nonoperative rehab. In other words, 70% of the potential noncopers actually regained dynamic knee stability and returned to preinjury activity levels without surgery!
Is the risk of knee osteoarthritis (OA) later in life higher after an ACL injury?
A 2020 cohort study found that there was a significantly increased risk of developing knee osteoarthritis (OA) later in life after knee injury in adolescence. This included injuries such as ACL tears, meniscus tears, and tibial fractures. But this study didn’t address whether or not ACL surgery versus no surgery impacted the rate of knee OA.
Another 2019 systematic review discovered that patients with ACL injury were 4x more likely to develop knee OA than somebody who did not have an ACL injury. When the knee injury involved the ACL and the meniscus, the risk increased to 6x greater compared to an uninjured knee.
Lastly, a 2020 systematic review found that the risk of knee OA was higher, but that the risk of meniscus injury was lower after surgical treatment of an ACL rupture (compared to non-surgical). The risk for a re-tear or additional ACL surgery was unrelated to treatment type (surgery versus no surgery). It was found that the surgical groups had less knee laxity compared to nonsurgical groups (that’s a good thing, as we don’t want joints that are too lax after injury). For this particular systematic review, the studies reviewed were 10 year follow ups.
What is the Cross Bracing Protocol?
There is new and promising evidence that a nonsurgical, Cross Bracing Protocol (CBP) can promote healing of the ACL within 3 months as evidenced by MRI.
The Cross Bracing Protocol
The knee is immobilized at 90° of flexion for 4 weeks after acute ACL rupture. After 4 weeks, knee flexion range of motion is increased at weekly increments until week 10 when unrestricted range of motion is allowed. At week 12, the brace is removed. Weight-bearing is always encouraged within the available range. Throughout the CBP, the patient also participates in exercise-based rehabilitation supervised by a physical therapist until the point of return-to-sport.
In this study, 90% of patients treated with the CBP had evidence of ACL healing on 3-month MRI. More ACL healing was associated with better patient-reported knee function and quality of life, less knee laxity, and higher return-to-sport rates.
So yes, the ACL can heal spontaneously without surgery for some individuals.
How long should I wait before having ACL surgery?
If you do decide to have surgery, it is recommended to wait at least 3 weeks post injury. This is in order to avoid something called arthrofibrosis (basically we want to avoid excessive scar tissue formation and adhesions). If that occurs, you will have a very stiff knee joint, causing complications post-operatively.
Besides time, it is also recommended that you wait for swelling to decrease, for knee range of motion to be restored, and for your quadriceps muscles to have sufficient strength (80% of the the uninvolved side). One study showed that having ACL reconstruction surgery before sufficient quad strength was restored resulted in significantly greater strength deficits two years following surgery.
ACL Reconstruction Surgery vs Non-op Rehab
A 2021 meta analysis found no differences in the prevention of knee OA or patient-reported outcomes and activity level at 5 and 10 years follow-up.
However, the same study found that the surgical treatment group had better objective knee function and a lower rate of secondary meniscectomies when compared to the non-surgical rehab group.
Time Considerations
While conservative rehab alone may work for some athletes, are you willing to invest the time (6 months to a year) for rehab before deciding on surgical treatment?
Not competing? You can try the cross bracing protocol, wait 3 months, and the ACL may or may not heal spontaneously. The option for surgery is still going to be there and you can decide on it after giving yourself the chance to heal spontaneously.
Closing Remarks
Making a decision on whether or not to have ACL surgery can be difficult. We always recommend discussing with an orthopedic surgeon, and getting multiple opinions if you don’t feel comfortable making a decision right away. With that being said, if you are an athlete and trying to get back to competition level, it is still typically recommended for you to have surgery. The risk of additional knee injury (like meniscus tears) can be high, especially for somebody in a cutting sport.
If you are an athlete dealing with an ACL injury, and would like to work with us, contact us below to speak with a physical therapist.
Disclaimer: This is not intended to be formal medical advice. Your individual needs should be met by the appropriate health care practitioners. Please consult with a trusted provider.
Dr. Vincent Liu PT, DPT
Dr. Paul Nasri PT, DPT, OCS, COMT
Doctor of Physical Therapy
The Game Plan Physical Therapy