Torn ACL Recovery Time?

How quickly can you get back to sports after a torn ACL? Can an ACL tear heal without surgery? If you have surgery, how long does it take to get back to sports? Let’s dig in to define torn ACL recovery time.

What is the ACL?

Medical illustration showing the anatomy of a normal knee versus a knee with a torn ACL


The ACL is a ligament that lives in the middle of the knee that keeps the tibia (leg bone) from sliding forward and rotating against the femur (thigh bone). It has two bands that cross over each other, which adds to its ability to stabilize leg rotation. It can be torn when pivoting or getting hit in the knee and treatments include physical therapy, biologic augmentation to prompt healing like the Perc-ACLR procedure, or surgical reconstruction (aka Surgical ACLR). In the surgical procedure, usually, a cadaver ligament or part of a tendon from the patient (autologous graft) is used to replace the native ligament.

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Can an ACL Tear Heal Without Surgery?

In looking into torn ACL recovery time, the first question is can the ACL tear heal on its own? What patients are often told is that a torn ACL will never repair itself. This concept that a torn anterior cruciate ligament couldn’t mend on its own began in the 1930’s (1). In the 1980’s, surgeons attempted to suture the two torn ends back together, but this procedure often ended in failure (2).

However, research was published in 2012, where researchers reviewed the MRIs of patients with complete ACL tears and who had surgery delayed for one reason or another. They showed that some of the complete ACL tears did successfully heal without surgery (3). It was about this same time that surgeons started poking holes in the bones where the ACL attached to release bone marrow stem cells to promote more ACL healing (4). This was called “marrow stimulation”. While this was surgery, it showed you could promote healing. However, could a torn ACL be stimulated to heal with only a precise image-guided injection of stem cells?

We first began treating partial ACL tears through injecting bone marrow stem cells in about 2012 with the goal of shortening torn ACL recovery time. We were surprised to see many ACL tears completely heal on MRI. Later we tackled selected completely torn ligaments and saw the same thing, that many of these tears were healing completely on follow-up MRIs without any surgery (5,6). These patients also went back to full sports activity at a very high rate and low re-tear rates. They also tended to be back to sports at 6 months or sooner whereas their peers that had surgery were often not back to play until a year after surgery. Other physicians have also shown that injecting platelet-rich plasma into partial ACL tears (in patients who are not surgical candidates) can produce good results (7). To see what a precise injection of the ACL looks like, see my video below:

Torn ACL Recovery Time?

ACL tears break into three major types:

  • Partial
  • Complete – non-retracted
  • Complete retracted

A partial tear is when only some of the ligament fibers are torn and the ligament is pretty much otherwise intact. These usually heal with time and physical therapy. Full healing can take 3-6 months, less time if you’re younger and more if you’re older. However, the patient may feel fine within the first 1-2 months. If the knee ligament is loose, an ACL brace is recommended for any running, cutting, or pivoting activities while the ligament is still healing.

Regrettably, ACL MRI reports often don’t distinguish between non-retracted and retracted tears. A retracted tear is one that pulls back like a rubber band. A non-retracted tear means that all of the fibers of the ACL are blown out, but the ligament is still intact. A retracted tear will require surgery, while a complete non-retracted tear can often be treated through a stem cell injection without surgery, as described above.

If you have surgery, what will your torn ACL recovery time be? In one recent study, it took NFL players 50 weeks to return to play after ACL surgery (12). Another study looked at an accelerated protocol trying to get athletes back to sports more quickly (at 6 months) and found that only 19% could get back that quickly (13). Hence, despite what some surgeons state, it’s very unlikely that you will back playing sports at 6 months if you need surgery!

Learn about Regenexx procedures for acl conditions.

How Many People Return to their Usual Sports with Surgery?

This is an interesting question with likely a few answers. For the average person, in one recent study, 61% had returned to their pre-injury activities at one year after surgery (8). So not fantastic. For NFL linemen it was 64% (10). Of 344 professional athletes in a different study, 87% returned to play (11). NHL players went back more often and sooner, while NFL athletes had shorter careers after surgery with only a 60% return to play rate. Both NBA and NFL players showed poorer performance after the first season, while NBA players recovered over time to their pre-surgery performance, NFL players did not. Finally, in one recent study, the authors believed they could improve the return to play rate by 10 return to sports centered physical therapy visits (9).

The upshot? Torn ACL recovery time all depends on what happened to your ligament and how it’s treated. If you have surgery, don’t expect to be back playing in much less than a year. If you have the type of ACL tear that can be treated through newer precise injection techniques using x-ray guidance, then return to sports should be much faster. And if you’re lucky enough to have a partial ACL tear, you can get back to sports even faster!



(1) Wittek A. Replacement of the cruciate ligament with patellar tendon. Schweiz Med Wochenschr. 1935;65:103–104. Link to discussion

(2) Sandberg R, Balkfors B, Nilsson B, Westlin N. Operative versus non-operative treatment of recent injuries to the ligaments of the knee. A prospective randomized study. J Bone Joint Surg Am. 1987;69:1120–1126.

(3) Costa-Paz M, Ayerza MA, Tanoira I, Astoul J, Muscolo DL. Spontaneous healing in complete ACL ruptures: a clinical and MRI study. Clin Orthop Relat Res. 2012;470(4):979–985.

(4) Vavken P, Murray MM. The potential for primary repair of the ACL. Sports Med Arthrosc. 2011;19:44–49.

(5) Centeno CJ, Pitts J, Al-Sayegh H, Freeman MD. Anterior cruciate ligament tears treated with percutaneous injection of autologous bone marrow nucleated cells: a case series. J Pain Res. 2015;8:437–447.

(6) Centeno C, Markle J, Dodson E, et al. Symptomatic anterior cruciate ligament tears treated with percutaneous injection of autologous bone marrow concentrate and platelet products: a non-controlled registry study. J Transl Med. 2018;16(1):246.

(7) Koch M, Mayr F, Achenbach L, et al. Partial Anterior Cruciate Ligament Ruptures: Advantages by Intraligament Autologous Conditioned Plasma Injection and Healing Response Technique-Midterm Outcome Evaluation. Biomed Res Int. 2018;2018:3204869.

(8) Webster KE, McPherson AL, Hewett TE, Feller JA. Factors Associated With a Return to Preinjury Level of Sport Performance After Anterior Cruciate Ligament Reconstruction Surgery. Am J Sports Med. 2019 Sep;47(11):2557-2562. doi: 10.1177/0363546519865537.

(9) Capin JJ, Failla M, Zarzycki R, et al. Superior 2-Year Functional Outcomes Among Young Female Athletes After ACL Reconstruction in 10 Return-to-Sport Training Sessions: Comparison of ACL-SPORTS Randomized Controlled Trial With Delaware-Oslo and MOON Cohorts. Orthop J Sports Med. 2019;7(8):2325967119861311. Published 2019 Aug 1. doi:10.1177/2325967119861311

(10) Cinque ME, Hannon CP, Bohl DD, et al. Return to Sport and Performance After Anterior Cruciate Ligament Reconstruction in National Football League Linemen. Orthop J Sports Med. 2017;5(6):2325967117711681. Published 2017 Jun 20. doi:10.1177/2325967117711681

(11) Mai HT, Chun DS, Schneider AD, Erickson BJ, Freshman RD, Kester B, Verma NN, Hsu WK. Performance-Based Outcomes After Anterior Cruciate Ligament Reconstruction in Professional Athletes Differ Between Sports. Am J Sports Med. 2017 Aug;45(10):2226-2232. doi: 10.1177/0363546517704834.

(12) Okoroha KR, Fidai MS, Tramer JS, Elmenini J, Makhni EC, Verma NN, Bach BR, Moutzouros V. Length of Time Between Anterior Cruciate Ligament Reconstruction and Return to Sport Does Not Predict Need for Revision Surgery in National Football League Players. Arthroscopy. 2019 Jan;35(1):158-162. doi: 10.1016/j.arthro.2018.08.007. DOI: 10.1016/j.arthro.2018.08.007

(13) Raoul T, Klouche S, Guerrier B, El-Hariri B, Herman S, Gerometta A, Lefevre N, Bohu Y. Are athletes able to resume sport at six-month mean follow-up after anterior cruciate ligament reconstruction? Prospective functional and psychological assessment from the French Anterior Cruciate Ligament Study (FAST) cohort. Knee. 2019 Jan;26(1):155-164. doi: 10.1016/j.knee.2018.11.006.

Chris Centeno, MD is a specialist in regenerative medicine and the new field of Interventional Orthopedics. Centeno pioneered orthopedic stem cell procedures in 2005 and is responsible for a large amount of the published research on stem cell use for orthopedic applications. View Profile

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NOTE: This blog post provides general information to help the reader better understand regenerative medicine, musculoskeletal health, and related subjects. All content provided in this blog, website, or any linked materials, including text, graphics, images, patient profiles, outcomes, and information, are not intended and should not be considered or used as a substitute for medical advice, diagnosis, or treatment. Please always consult with a professional and certified healthcare provider to discuss if a treatment is right for you.

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