Can you repair an ACL without a surgery?

Marc Darrow MD

Marc Darrow, MD, explains alternative treatments for lumbar spinal stenosis including Stem Cell Therapy and Prolotherapy.

 “My ACL is hanging on by a thread – can I regrow the ligament”

“Tears of the anterior cruciate ligament (ACL) are very frequent injuries, particularly in young and active people. Arthroscopic reconstruction using tendon auto- or allograft represents the gold-standard for the management of ACL tears.

Interestingly, the ACL has the potential to heal upon intensive non-surgical rehabilitation procedures.

Several biological factors influence this healing process as local intraligamentous cytokines (healing growth factors within the ligament) and mainly cell repair mechanisms controlled by stem cells or progenitor cells (a cell that can morph itself into something else that aids in repair).

Understanding the mechanisms of this regeneration process and the cells involved may pave the way for novel, less invasive and biology-based strategies for ACL repair.” 1

Understanding how an ACL heals – even a complete rupture has lead doctors to continuously look at bio-materials – blood platelets and stem cells. One of the things they look at is “Scaffolding.” This is a surgical procedure where a cartilage patch is placed over a cartilage defect and them “pasted in with PRP or stem cell gel.” However in some instances the body may make its own scaffolding out of pooled blood and use this blood as the foundation to regenerate a ligament – even a complete ruptured ACL.

Below is a case I reported on earlier that appeared in the literature

A recent case study of a 12 year old boy who regrew a completely torn ACL

Doctors shared a case history of a 12 year old boy who grievously injured his knee after being hit by a car – the boy was also a high level hockey player. What makes this story so amazing is that the knee damage was so severe in regard to broken bones, that an ACL reconstruction surgery had to be postponed until the other damaged healed. When doctors went in 14 months later to start the processes of ACL reconstruction, they found a completely regenerated ACL.

The attending doctors point out that the body of evidence says that this should not have happened. The medical literature states a completely ruptured ACL does not heal because blood and healing cells cannot reach it.

Yet, their patient with traumatic knee injury with multiple ruptured ligaments healed over the course of 20 months.

It is likely that bracing associated with the patient’s second surgery and delayed union of his tibial fracture allowed healing tissue to be protected from excessive stress until it remodeled with sufficient strength. It is possible that intra-articular scar formation contributed to his healing capacity. (Possibly the blood scaffold.)

At age 14 the boy returned to playing competitive hockey – and two and a half years later – still playing with no adverse effects to his knee.2

In the above scenario and in the surgical procedure, the common factor in ACL healing is time. However many active people do not have the time to rehab. This lack of patience creates more patients. In Anterior cruciate ligament reconstruction the overall incidence rate of having to go through it again within 24 months is 6 times greater than someone who has never had an ACL tear.

That was research presented at the American Orthopaedic Society for Sports Medicine’s (AOSSM) Annual Meeting 2013.

  • The doctors found that female athletes after Anterior cruciate ligament reconstruction demonstrated more than four times greater rate of injury within 24 months than their healthy counterparts.

Researchers looked at  78 patients (59 female, 19 male) between 10 and 25 years old, who underwent Anterior cruciate ligament reconstruction and were ready to return to a pivoting/cutting sport and 47 healthy, control individuals. Each subject was followed for injury and athletic exposure for a 24-month period after returning to play.

  • Twenty-three of the Anterior cruciate ligament reconstruction individuals and 4 control subjects suffered an ACL injury. Within the Anterior cruciate ligament reconstruction group, there also appeared to be a trend for female subjects to be two times more likely to suffer an injury on the opposite knee than on the previously injured one.


ACL tears

Overall, 29.5% of athletes suffered a second ACL injury within 24 months of returning to activity with 20.5% sustaining an opposite leg injury and 9.0% incurring graft re-tear injury on the same leg. A higher proportion of females (23.7%) suffered an opposite leg injury compared to males (10.5%).1

Recently, doctors addressed the epidemic of anterior cruciate ligament injuries among young athletes, and the large number of patients who have surgery to reconstruct a torn ACL and undergo a second knee operation later on. (April 2015 findings)

“This is the first study to evaluate, on a population level, the percentage of patients under age 21 who had subsequent ACL or non-ACL knee surgery following a primary Anterior cruciate ligament reconstruction,” said Emily Dodwell, MD, MPH, lead investigator of the study by researchers at Hospital for Special Surgery (HSS) and a pediatric orthopedic surgeon at Hospital for Special Surgery in New York City.

Compiling statistics from a New York State database, researchers found that eight percent of patients with a primary ACL reconstruction had another ACL surgery, and 14 percent had non-ACL knee surgery at a later date.

Researchers noted that the study may underestimate the actual number of repeat ACL tears, as the database only included patients who underwent surgery, and did not include those who chose not to have additional surgery.

“The increasing rate of ACL injuries is concerning, although not surprising given greater participation in sports,” Dr. Dodwell said. The study noted that children are starting sports at a younger age, playing for longer durations with greater intensity, and often concentrating on a single sport year round, resulting in overuse and acute injuries.

“For young people who have primary surgery to reconstruct a torn ACL, it is troubling that they have relatively high rates of subsequent ACL reconstruction or surgery for another knee injury. Further research is needed to determine factors associated with subsequent injury and surgery so we can implement strategies to keep our youth safe while engaging in sports,” Dr. Dodwell said.

ACL Rupture Prevention

The internet is filled with articles on how to prevent ACL tears. They range from strength training, aerobic training, nutrition, coordination exercises, balance and posture, knee bracing, etc. But what about the high risk knee? The knee that has already been compromised by wear and tear and previous injury. How can ACL injury be prevented?

The Ligament

If you look at a picture of the human anatomy, you will see that muscles are big and red. They are red because of the abundant blood supply that runs through them that helps them grow and repair. Ligaments on the other hand are small and white and resemble thick rubber bands. They are small and white because they do not have an abundant blood supply run through them and because of this, usually do not heal well from injury and will in the case of tears – require surgery.

Over the course of an athlete’s season ligaments become weaker, they lose elasticity, and are prone to injury. This is when pain, soreness, and loss of strength appear in the knee.

The treatment causes the injury. It is about this time that icing, anti-inflammatory medications, and knee bracing or taping will be tried to get the player through the season. We have found in our practice that these remedies actually increased the risk of ACL tear rather than prevented it. This observation is supported in many medical papers citing the pros and cons of knee bracing and taping and circulatory and healing disruption by icing.

Further, the player will begin to over compensate for the injured knee and in doing so puts the “healthy knee” at greater risk for severe ACL damage. In addition chronic ankle sprains have been cited as a cause of higher risk to ACL tear. So not healing an injury completely puts the athlete at risk for ACL tear.

This is when a patient will come into the office and say their ACL is a ticking time bomb that is hanging on by a thread.

One thing that the treatments described above have in common is that they weaken ligaments. Icing, as stated disrupts circulation needed to bring the healing cells to damaged ligaments, anti-inflammatory medications have been shown to increase the risk of ligament damage by suppressing immune function. Knee braces – there is no conclusive evidence they work and may only trick the athlete into a comfort level that their knee is protected.

To prevent devastating ACL injuries, athletes need to look into a treatment that grows and strengthens their ligaments – Stem Cell, Platelet Rich Plasma therapy and Prolotherapy.

In 2009, Prolotherapy doctors published a case history of a patient with a complete ACL rupture. The patient was an 18 year old female who sustained a right knee injury during a downhill skiing accident. MRI revealed a high-grade partial versus a complete rupture. She deferred surgical treatment. At 21 weeks post-injury, with unstable gait and an inability to climb stairs, she consented to undergo Prolotherapy injections. She received 7 Prolotherapy sessions over a 15 week period. At-home exercises were initiated at the 3(rd) Prolotherapy session. The results were that the patient improved. Walking on flat ground improved 4 weeks after initiation of Prolotherapy; she could ride a stationary bicycle for 30 minutes by 12 weeks. By 15 weeks, the patient had no instability climbing and descending stairs, the anterior drawer test was negative and MRI showed an intact ACL with fibrosis. Subsequently, she returned to full sport activity.3

This was not the only documented research on ACL repair and Prolotherapy. Doctors found that in patients with symptomatic anterior cruciate ligament laxity and weakening, intermittent Prolotherapy injections resulted in clinically and statistically significant improvement in ACL laxity, pain, swelling, and knee range of motion4

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1. Hirzinger C, Tauber M, Korntner S, Quirchmayr M, Bauer HC, Traweger A, Tempfer H. ACL injuries and stem cell therapy. Arch Orthop Trauma Surg. 2014 Nov;134(11):1573-8. doi: 10.1007/s00402-014-2060-2. Epub 2014 Jul 30.

2. Reported by Deren Bagsby, MD, George Gantsoudes, MD, and Robert Klitzman, MD Am J Orthop. 2015;44(8):E294-E297.

3. Grote W, Delucia R, Waxman R, Zgierska A, Wilson J, Rabago D. Repair of a complete anterior cruciate tear using prolotherapy: a case report.Int Musculoskelet Med. 2009 Dec 1;31(4):159-165

4. Reeves KD, Hassanein KM. Long-term effects of dextrose prolotherapy for anterior cruciate ligament laxity. Altern Ther Health Med. 2003 May-Jun;9(3):58-62.

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About Marc Darrow MD, JD

Marc Darrow, MD, JD, is one of the leading physicians practicing Stem Cell Therapy, Platelet Rich Plasma Therapy, and Prolotherapy. Email with questions about this article to