It happened suddenly. There was abrupt pop followed by severe pain and swelling in the knee. Your doctor thinks you have injured your ACL. What is the Anterior Cruciate Ligament? What are the three major causes of ACL tears? What are the symptoms of an ACL tear? Are there different types of ACL tears? What is ACL surgery? What are the complications associated with ACL surgery? What are effective ACL tear treatments without Surgery? Meet KG a 14-year-old soccer enthusiast who healed her ACL with her own stem cells. Let’s dig in.
What Is the Anterior Cruciate Ligament? (ACL)
The knee has four major ligaments which are illustrated to the right. They include:
Anterior Cruciate Ligament (ACL)
Posterior Cruciate Ligament (PCL)
Medial Collateral Ligament (MCL)
Lateral Collateral Ligament (LCL)
The Anterior Cruciate Ligament (ACL) extends from the thigh bone (femur) to the shin bone (tibia) and limits forward and rotational movement of the knee. It is a key stabilizer in the knee. It is composed of two separate ligament bundles which include the anterior medial and the posterior lateral. The ACL prevents excessive forward and rotational movement.
What Causes an ACL to Tear? (Direct, Indirect, and Noncontact)
A person or object directly strikes the knee. This is common in many sports especially football and soccer.
A person or object strikes a part of the body other than the knee itself causing excessive forces to be transferred to the knee. Examples include basketball and martial arts.
Examples include hyperextension of the knee, incorrect landing, abrupt stop, and pivoting with the foot firmly planted. Noncontact mechanisms account for 60-70% of ACL injuries (2).
What Are the Symptoms of an ACL Tear?
How to tell if you tore your ACL? There are numerous signs and symptoms of an ACL tear. Symptoms may vary from patient to patient and upon the severity of the tear. The most common symptoms are:
- A loud pop
- Severe pain
- Rapid swelling
- Reduced range of motion
- Knee “gives away” when bearing weight
- Difficulty or inability to walk or stand
Are there Different Types of ACL Tears? (Yes)
Not all ACL tears are the same. It is important to know the specific type of tear. There are three principal types of ligament tears: partial thickness, complete thickness, and complete thickness with retractions
This is where a portion of the ligament is torn
Full Thickness, Non-Retracted Tear
This is a more severe injury. The tear extends across the entire surface of the ligament but the ligament is still held together by small remaining fibers.
Full-Thickness Retracted Tear
This is the worst-case scenario. The tear extends across the entire surface of the ligament and the ligament itself rips apart like a rubber band. The single ACL ligament is ripped apart with two ends that are no longer connected. A full-thickness, retracted ACL tear requires surgery.
What Is ACL Surgery?
ACL surgery is a major surgery that involves cutting out your torn ACL and replacing it with a GRAFT. What is a graft? It is a tissue taken from one site that is used in a different site in the body. The grafts themselves are not ligaments but rather are tendons taken from other areas of the body. There a 4 different types of grafts used in ACL surgery (3). They include:
Hamstring Tendon Graft
The hamstring is the large muscle in the back of the thigh
Patellar Tendon Graft:
The patellar tendon is the large tendon in the front of the knee that connects the knee cap to the shin
Quadriceps Tendon Graft
The quadricep is the large muscle in the front of the thigh.
Cadaveric Tendon Graft
A cadaver is an individual that has died but has given permission to use their body tissues for medical use. They may be young or old, female or male.
Note that all the grafts used in ACL surgery are tendons and NOT ligaments.
Complications Associated with ACL Surgery
ACL surgery is a major surgery that is performed at a hospital or ambulatory surgery center. A general anesthetic or spinal block is performed along with sedation. There are multiple possible complications associated with ACL surgery. The most common include.
Tearing of the Graft
The two bundles of the native ACL are replaced with a single tendon or cadaveric graft that is not as strong. The result is injury and retearing of the new graft. The statistics are alarming. The overall incident rate of a second ACL injury with 24 months after ACL reconstruction and return to sports was 6 times greater than in a healthy population (4). At 5 years follow up after ACL reconstruction 12% of patients sustained a second ACL injury (5). At 15 years followup after ACL surgery 29-34% of patients suffered a second ACL injury (6).
A person’s own native ACL has two bundles that are critical to the stability of the knee. Surgical reconstruction removes the two native bundles which are then replaced with a single bundle graft. This single graft can lead to knee instability which in turn can create excessive wear and tear on the cartilage, meniscus, tendons, and ligaments.
Muscle control and performance are compromised as the fibers in the knee that provide location information in the knee work poorly after surgery (7). Balance is also compromised in patients one year after ACL reconstruction (8). Many professional athletes fail to return to their pre-surgery level of performance.
Increased Risk of Knee Arthritis
A recent study that followed 164 patients at a mean of 14 years after ACL reconstruction demonstrated a 3 fold increase in osteoarthritis when compared to the opposite healthy knee (9). Why? The ACL graft is no match to your native two bundle ligament. Inserting the graft at the time of surgery can be challenging. In many cases, the implanted graft is too loose which allows for instability and places the cartilage and meniscus at risk for additional damage. Conversely, if the graft is too tight the excessive forces can lead to cartilage breakdown and onset of arthritis.
ACLGraft Does Not Grow
In young patients who have not finished growing, ACL surgery is particularly problematic. The tendon graft can not grow. As the child continues to grow, both the thigh bone and shin bone lengthen. The space between the two bones also increases. Unfortunately, the ACL graft does not lengthen. This can compromise proper growth of the knee joint and future knee function and performance. Additional surgeries are often required.
To learn more about ACL surgery and its risks please click on the video below.
Are there Alternatives to ACL Surgery?
The Regenexx Percutaneous ACL Repair (Perc-ACLR) procedure is an advanced x-ray guided procedure where a patient’s own stem cells are injected into the damaged/torn ACL. Stem cells are your body’s powerhouses of healing and can coordinate cells throughout the body to assist in the reorganization and healing of ligament injuries. We have published our results in two peer-reviewed journals (10)(11). MRI images of the ACL prior to and following stem cell treatment have demonstrated profound healing. To review pre and post-procedure MRI’s please click on the video below.
ACL Tear Treatment Without Surgery? Meet KG
I am so very excited to share with you our most recent success story at the Centeno-Schultz Clinic. Meet KG who is a 14-year-old avid soccer enthusiast who regrettably sustained a traumatic injury while skiing in December 2019. She tore her ACL in her right knee. It was a significant injury as it was a full-thickness tear. She and her family declined surgery and opted to use her own bone marrow-derived stem cells. In January 2020 KG underwent the Regenexx SD procedure where her own stem cells were carefully injected into the area of injury in her right ACL. The procedure was performed under x-ray guidance and requires a very high level of expertise.
Rehabilitation after stem cells required the use of a knee brace followed by specific, graduated physical therapy exercises and strengthening. At 9 months KG was noted to have notable clinical and radiographic improvement. Last week KG returned to the clinic for a follow-up. A new MRI 1year after the procedure demonstrated complete healing with no evidence of prior tear. Clinically she is pain-free with no physical restrictions and has started soccer practice. Below is her knee MRI before and after stem cell injection.
The MRI’s above are images of the knee from the side view. The thigh bone (femur) is on the top whereas the tibia is towards the bottom. The ACL is outlined with the blue dashed line. The purple arrow on the left identifies the tear in the ACL. The same ACL tear is healed on the right using her own stem cells!
The procedure is technically challenging and can not be performed by your PCP or orthopedic surgeon. A patient’s stem cells are harvested in the morning and then reinjected into the damaged ACL later that same day. All injections are performed under intermittent x-ray. Why? This ensures the proper placement of stem cells into the ACL tear. Again, this procedure requires advanced training and can not be performed by your PCP or orthopedic surgeon. Click below to see my Centeno-Schultz Clinic ACL injections.
The ACL is a key stabilizer in the knee. It is susceptible to injury due to direct contact, indirect contact, and other causes. How to tell if you tore your ACL? The signs and symptoms of an ACL tear include a loud pop, severe pain, rapid swelling, instability, and difficulty with walking or standing. MRI is the best study to diagnose an ACL injury. Surgery is not the best option as it has multiple complications which include re-tears, knee instability, diminished performance, and risk for arthritis. A novel non-surgical procedure called Perc-ACLR (percutaneous ACL reconstruction) uses a patient’s own bone marrow-derived stem cells to repair ACL injuries. Two peer-reviewed studies have demonstrated its success in allowing patients to avoid the risks of surgery and viral contamination. KG is a 14 y/o soccer enthusiast who torn her ACL and successfully used the own stem cells to heal the ACL tear. The Perc-ACLR allowed KG to avoid the risk and long-term complications associated with ACL surgery. She has returned to soccer practice eager to compete in the spring.
If you or a loved one has sustained an ACL injury know that there are effective ACL tear treatments without surgery. Your own stem cells, when precisely injected into the area of damage, can promote an increase in blood flow and healing. Surgery has significant risks and complications, particularly in young athletes.
Schedule telemedicine or in-office evaluation with a board-certified, fellowship-trained physician who can advise you on your best treatment option. If left untreated an ACL can progress leading to meniscus and cartilage damage. Act now so you or your aspiring national superstar can get back on the field.
Enjoy my Facebook LIVE on the subject, Below:
1.Spindler KP, Wright RW. Clinical practice. Anterior cruciate ligament tear. N Engl J Med. 2008;359(20):2135-2142. doi:10.1056/NEJMcp0804745
2.Cimino F, Volk BS, Setter D. Anterior Cruciate Ligament Injury: Diagnosis, Management, and Prevention. Am Fam Physician. 2010;82(8):917-922
3.Macaulay AA, Perfetti DC, Levine WN. Anterior cruciate ligament graft choices. Sports Health. 2012;4(1):63-68. doi:10.1177/1941738111409890
4.Paterno MV, Rauh MJ, Schmitt LC, Ford KR, Hewett TE. Incidence of Second ACL Injuries 2 Years After Primary ACL Reconstruction and Return to Sport. Am J Sports Med. 2014;42(7):1567-73.doi: 10.1177/0363546514530088.
5.Salmon L, Russell V, Musgrove T, Pinczewski L, Refshauge K. Incidence and risk factors for graft rupture and contralateral rupture after anterior cruciate ligament reconstruction. Arthroscopy. 2005;21(8):948-57.DOI: 10.1016/j.arthro.2005.04.110.
6.Leys T, Salmon L, Waller A, Linklater J, Pinczewski L. Clinical results and risk factors for reinjury 15 years after anterior cruciate ligament reconstruction: a prospective study of hamstring and patellar tendon grafts. Am J Sports Med. 2012;40(3):595-605.DOI: 10.1177/0363546511430375.
7. Patterson MR, Delahunt E. A diagonal landing task to assess dynamic postural stability in ACL reconstructed females. Knee. 2013;20(6):532-6. DOI: 10.1016/j.knee.2013.07.008.
8. Bączkowicz D, Skomudek A. Assessment of neuromuscular control in patients after anterior cruciate ligament reconstruction. Ortop Traumatol Rehabil. 2013;15(3):205-14.DOI: 10.5604/15093492.1058410.
9.Barenius B, Ponzer S, Shalabi A, Bujak R, Norlén L, Eriksson K. Increased risk of osteoarthritis after anterior cruciate ligament reconstruction: a 14-year follow-up study of a randomized controlled trial. Am J Sports Med. 2014;42(5):1049-57. DOI: 10.1177/0363546514526139.
10. 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. doi: 10.1186/s12967-018-1623-3.
11. 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;8:437-47. doi: 10.2147/JPR.S86244.