ACL Tear Symptoms, Causes + 7 Ways to Recover - Dr. Axe

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6 Ways to Boost ACL Tear Recovery


ACL tear - Dr. Axe

ACL tears and sprains are some of the most common injuries among athletes who play “high-risk sports,” including basketball, soccer and football, as well as skiing. But believe it or not, the majority of ACL injuries occur through non-contact mechanisms, according to the American Academy of Orthopaedic Surgeons. (1) And while male athletes may get the most publicity when it comes to career-stalling ACL tears, female athletes actually have a higher incidence of ACL injury than male athletes in certain sports.

How do you know if you have a torn ACL? Is it painful to tear your ACL? Usually, yes, and sometimes it’s very painful, although some people don’t experience much pain initially. Can you still walk if you have a torn ACL? Most people who just experienced an ACL tear will feel unstable in their knees and have noticeable knee pain, throbbing and/or swelling, plus limited range of motion in their lower body that gets worse with time. (2)

All of these symptoms make it difficult to bear weight, walk and even balance. Every year about 200,000 Americans undergo ACL reconstructive surgery, but is this always necessary? Depending on the individual, other treatment options like physical therapy, strength-building exercises and knee bracing may be enough to support ACL recovery. (3)

What Is the ACL?

“ACL” stands for the anterior cruciate ligament. Where is your ACL located? The ACL is one of the four main ligaments within the knees; the other three are the medial collateral (MCL), lateral collateral (LCL) and posterior cruciate (PCL) ligaments. The anterior cruciate ligament is a thick cord of tissue that runs diagonally down the middle of the knees. It’s about as thick as your index finger and made up of woven strands of connective tissue that help it withstand force.

The knees are major hinge joints that are formed from bones, cartilage, ligaments and tendons. The ACL is responsible for connecting two of the major bones of the legs, the femur (thigh bone) and the tibia (shin bone). Some of the roles that the ACL has include providing the knee with stability and preventing the tibia from sliding out in front of the femur.

What Is an ACL Tear?

An ACL tear is an injury to the anterior cruciate ligament, which can range from a mild strain to a complete tear. It’s estimated that about half of all ACL injuries also occur with damage to other ligaments, bones and cartilage in the knee, including the meniscus and articular cartilage.

ACL Tear Symptoms:

The most common torn ACL symptoms include:

  • Pain and swelling in the affected knee (swelling usually worsens considerably within hours of the injury taking place)
  • Feeling unstable in the knee
  • Reduced range of motion and stiffness
  • Tenderness and discomfort along the joint line when standing or walking
  • In some cases a pop or snap may be heard

Rather than having a torn anterior cruciate ligament, you might actually be suffering from torn meniscus symptoms if you’re feeling pain in your knee. It’s also common to experience both an ACL tear and damage to the shock-absorbing cartilage in the knee (meniscus) at the same time.

A torn meniscus is another common knee injury caused by twisting/rotating of the knee that damages tissue. The meniscus is a piece of cartilage that cushions the space between the shinbone and thighbone. A meniscus tear can be very painful, sometimes even debilitating.

Torn meniscus symptoms usually include lots of swelling and stiffness, trouble extending/straightening the knee, pain when putting weight on the knee or walking, and feeling like the knee is locked in place. Sometimes a “popping sensation” will be felt when the injury happens, even causing a popping noise in some cases. (5)

ACL Causes:

A torn ligament in the knee can be caused by:

  • Non-contact mechanisms, meaning everyday activities like car accidents or work-related injuries (not contact sports). For example, the injury may be due to a fall, accident or crash, which causes direct contact with another surface or object.
  • An ACL tear or injury might also happen due to overextension of the knee joint, or due to quickly stopping when moving and changing directions.
  • Direct contact with another player while playing sports. An ACL tear is most likely to occur when a player is decelerating/stopping suddenly, pivoting or sidestepping, jumping and landing awkwardly, or playing aggressively and acting “out of control.”
  • Female athletes are at an increased risk for experiencing an ACL tear due to differences in muscular strength, neuromuscular control and conditioning, alignment of the legs and pelvis, and ligament laxity (their ligaments/joints tend to be looser). (6)
  • Those with other knee injuries or inflammation of the knee, such as iliotibial band syndrome, might be at an increased risk for injuries such as ACL tears.

ACL Tear Diagnosis:

Doctors will usually take X-rays of a patient’s knee if they suspect a torn anterior cruciate ligament has occurred. An ACL tear can also usually be seen on a magnetic resonance imaging (MRI) scan. An MRI is useful for identifying if other parts of the knee (like the other ligaments, meniscus cartilage, or articular cartilage) have also been damaged.

Additionally, a physical exam is usually done to check for increased forward movement of the tibia in relation to the femur, which indicates that the ACL has torn.

ACL Tear vs. ACL Sprain

Another way to describe an injured ligament is a “sprain.” The anterior cruciate ligament does not always need to fully tear; sometimes it is just over-stretched or partially torn. (7)

ACL injuries (tears and sprains) are classified by grades 1, 2 and 3, with a grade 3 ACL tear being the most severe.

  • Grade 1 ACL injuries include those that are “mild” but don’t cause a lot of instability or reduced range of motion.
  • Grade 2 ACL injuries are diagnosed when the ACL is stretched and partially torn. Grade 2 ACL injuries are actually rare, since the ACL usually tears completely or almost completely.
  • Grade 3 ACL tears are diagnosed when the ACL is torn completely, resulting in lots of instability.

ACL Tear Surgery

ACL surgery is performed to repair a tear by replacing damaged tissue with a substitute graft made of tendon, which can come from another part of the patient’s body (such as their hamstring or quadricep).

Can an ACL tear heal without surgery? Yes, it’s possible — however, doctors still recommend ACL surgery in many cases, depending on factors like how severe the ACL tear was (the degree of injury), the patient’s symptoms and the patient’s lifestyle (including how active they are and how eager they are to heal quickly).

  • When someone has a complete ACL tear, surgery is almost always recommended, but in the case of a partial ACL tear, it may or may not be necessary.
  • Surgery is also more common if multiple injuries occur at the same time, such as an ACL tear plus damage to the bones or cartilage of the knees.
  • ACL tear recovery time without surgery varies from person to person, depending on their age, general health, rehabilitation program, etc.
  • After an ACL tear occurs, recovery and rehabilitation usually lasts for at least three months, and sometimes longer if a grade 3 ACL tear (or complete ACL tear) occurred. It’s not uncommon for some ACL tear symptoms to linger for much longer, including instability and reduced athletic performance.
  • People who tend to heal more completely and quickly include those with: partial ACL tears and no instability symptoms, complete ACL tears with no knee instability during low-demand sports, those who are willing to give up high-demand sports and not lead very active lives, and children or young people who tend to have “open growth plates.”

6 Ways to Boost ACL Tear Recovery

1. Help Reduce Pain and Swelling

Immediately after an ACL tear occurs, put ice on your knee and elevate/raise your affected leg so that it’s held above the level of your heart. This will help to control swelling and hopefully pain. You can apply ice to the painful area for 15 minutes every two to three hours. Do not apply ice directly to your skin.

If pain becomes intense, you might choose to temporarily take an over-the-counter pain reliever, such as a nonsteroidal anti-inflammatory drug (NSAID) like ibuprofen. You should also follow up with your doctor right away, who might recommend you stay off your feet or use crutches to walk.

2. Physical Therapy

Physical therapy is almost always recommended in order to decrease ACL tear recovery time, especially if someone experiences a complete ACL tear and requires surgery. The American Academy of Orthopedic Surgeons states that “Physical therapy is a crucial part of successful ACL surgery, with exercises beginning immediately after the surgery.”

The goal of physical therapy is to help improve range of motion in the knee, as well as to improve leg strength and stability. One of the first milestones after a serious injury to the ACL is being able to fully straighten the knee and restore quadriceps control.

3. Leg-Strengthening Exercises

If you feel like your knee is unstable and “gives out” easily when you stand or walk, then this is a sign that visiting a physical therapist to learn certain strengthening exercises is probably necessary. A physical therapist can show you exercises and stretches that will improve functional use of the legs, balance, flexibility, stability and may help reduce your risk for future injuries.

For example, he or she might recommend that you foam roll your hamstrings and IT band and do stretches to release tight muscles, including the psoas muscles, that may lead to poor posture/instability in the lower body.

Following an ACL tear, you should focus on performing exercises to strengthen the stabilizing muscles around your knee, hips and glutes. Strengthening the quadriceps and hamstring muscles is important to restore full range of motion and to help build the ACL’s ability to bear weight. Core strength can also help to prevent future injuries because it allows you to land and pivot better. (8)

Keep in mind that it’s important to be patient during ACL recovery, since it can take 4–6 months to restore functionality of the legs. After getting clearance from your doctor, perform these exercises 1–3 times per day, for about four weeks until range of motion is restored. Then you can move onto more challenging exercises for the legs once you’re ready, such as stationary bicycling, squats and lightly weighted leg presses: (9, 10)

  • Sitting or laying calf and hamstring stretches (you can use a towel wrapped around your feet)
  • Quad sets, in which you tighten the muscles at the front of your leg and hold 3–5 seconds
  • Toe raises and ankle pumps
  • Heel props and slides, to work on lengthening the knee
  • Straight leg lifts while laying on your back
  • Hip extensions while laying on your stomach
  • Hamstring curls
  • Wall sits and wall slides
  • Calm shells
  • Side steps

4. Wearing a Knee Brace

Bracing the affected knee is often recommended if a torn ligament in the knee is causing instability. However, you don’t want to brace your knee without checking with your doctor, since in some cases bracing won’t help and might even make stiffness worse. Bracing might also be combined with crutches or use of another assistive device if you’re having trouble walking or getting around.

You should also, of course, be sure to wear footwear hat is appropriate for your level of activity or sport to help prevent injury, plus potentially orthotics if needed depending on your posture and symptoms.

5. Prolotherapy

Prolotherapy is a type of regenerative medicine that is used to treat both acute and chronic injuries, including a torn ligament, tendonitis, bulging disc, etc. Prolotherapy uses your body’s own platelets (called PRP, or platelet-rich plasma) and growth factors to heal damaged tissues naturally.

When you remove your body’s own stem cells from one location and re-inject them into another damaged area, the stem cells automatically know how to transform into the type of cells your body needs. In the case of a torn ACL, your stem cells adapt by turning into cells that form a strengthened, repaired ACL ligament. Platelets contain a number of proteins, cytokines and other bioactive factors that initiate and regulate basic aspects of natural wound healing.

One study conducted by the Department of Biometry at the University of Kansas Medical Center found that in patients with symptomatic anterior cruciate ligament laxity, prolotherapy treatment (intermittent dextrose injections) resulted in clinically and statistically significant improvement in ACL laxity, pain, swelling and knee range of motion. Prolotherapy is now considered an effective non-surgical treatment option for sport-related injuries, so if you’re a good candidate if you wish to avoid ACL surgery but want to return to your sport. (11)

6. Anti-Inflammatory Diet and Supplements

A healthy diet and supplements will help give your body the fuel it needs to heal. Plus, anti-inflammatory foods can help to reduce your risk for future injuries by helping you to maintain a healthy weight (which decreases strain on your joints) and improving recovery from exercise.

  • Consume plenty of fruits and vegetables, especially those high in vitamin C, sulfur and antioxidants like leafy greens, carrots, peppers, berries, onions, broccoli, garlic, asparagus and cabbage.
  • Get omega-3 fatty acids from wild-caught fish, especially benefit-packed salmon.
  • Focus on quality proteins like grass-fed meat, pasture-raised poultry, fish like sardines or mackerel, fermented dairy products, and eggs.
  • Add healthy fats to meals, such as coconut oil, olive oil, ghee, grass-fed butter, avocado, nuts and seeds.
  • Drink bone broth or use protein powder from bone broth.
  • Add antioxidant-packed herbs and spices to your meals. Collagen protein is another great option for supporting your body’s ability to repair connective tissue.
  • Limit or avoid excess sugar, hydrogenated oils (soybean oil, cottonseed oil, even canola oil), processed/refined grains, flour products, synthetic additives, processed meats and fast food.
  • Consider taking anti-inflammatory supplements such as turmeric, bromelain, glucosamine, chondroitin and omega-3 fatty acids.


Always visit your doctor or the emergency room if you experience any significant injury to your knee. This is especially important if your knee is very swollen, hot or if the foot is cool and blue after a knee injury.

You can help reduce your risk for an ACL tear by working on conditioning and stretching if you play contact sports. Before exercising, warm up stretches and movements that engage the muscles in the legs, hips and core are also helpful. Rolfing is known for its ability to improve athletic ability and may help protect athletes against injury by improving posture, lengthening constricted muscle fibers, relaxing areas of tension and improving ease of motion.

Final Thoughts

  • “ACL” stands for the anterior cruciate ligament, which is one of the four main ligaments within the knees.
  • A torn ACL occurs when the ACL is either partially damaged/strained or completely torn. Pain and symptoms vary depending on the grade of the ACL tear, with a grade 3 ligament tear being the most severe.
  • ACL tear symptoms include: pain and swelling in the knee, stiffness and throbbing, reduced range of motion of the knee, instability, and trouble walking and bearing weight.
  • When someone experiences a significant injury and is very unstable as a result, ACL tear surgery is usually recommended. However, it’s not always necessary for grade 1 or 2 tears, or in children/young adults who tend to heal more easily.
  • Aside from ACL tear surgery, other ACL tear treatment options include: icing and elevating right away, physical therapy, bracing, supplements.

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