What Are the Symptoms of a Torn ACL?

If you have a torn anterior cruciate ligament, you may experience a sudden “popping sound” in the knee joint, followed by immediate severe pain and rapid swelling. Most individuals also experience difficulty bearing weight, reduced range of motion, and knee instability during movement.

At Total Orthopedics and Sports Medicine, Dr. Charles Ruotolo, our leading sports medicine physician in East Meadow, provides expert evaluation for anterior cruciate ligament injuries. Through a detailed physical examination, he assesses knee stability, swelling, functional movement, and the presence of an ACL tear. He may also order advanced magnetic resonance imaging (MRI) to determine the severity of damage to ligament fibers. For expert evaluation and treatment, call us at 855-321-6784.

What Does a Torn ACL Feel Like?

Most ACL tears cause a sudden popping sensation in the knee, which may lead to swelling from internal bleeding in the joint. This swelling may also lead to stiffness and reduced range of motion, followed by chronic knee instability during standing or movement.

In fact, a PMC study found that 70% of patients with a partial or complete tear experience hemarthrosis, often accompanied by pain and limited range of motion. In more complex knee ligament injuries, surrounding structures, such as the medial collateral ligament or the patellar tendon, can also be compromised, leading to severe pain and joint dysfunction. Over time, if left untreated, these common ACL tear symptoms may cause persistent instability during routine movements and weight-bearing activities. Without proper treatment, your knee may lose strength, leading to reduced mobility and long-term functional impairment.

Who Is Most at Risk for Developing ACL Injuries?

According to Dr. Charles Ruotolo, people between the ages of 15 and 45, particularly individuals involved in high-intensity sports, face a higher risk of ACL injuries. Among these individuals, female athletes are more prone to ACL injuries due to differences in anatomy (narrower intercondylar notch), hormonal influences, and movement biomechanics that cause knee injuries during rapid motion. A SpringerLink study also reported that female athletes who experienced 2.5× higher peak knee abduction force and about 20% greater ground reaction forces during landing later sustained ACL injury. In addition, the following risk factors further increase the risk of developing ACL injuries:

Previous ACL Injury or Reconstruction

If you previously experienced an ACL tear or had surgical ACL reconstruction, you may face a higher risk of sustaining major ligament injury in either the same or opposite knee. It occurs due to changes in muscle strength, joint position, and movement patterns at the time of injury. Even after pain resolves and daily function improves, the knee may not distribute forces as efficiently as before. As a result, surrounding muscles may react more slowly or provide less support during sudden movements.

Moreover, if rehabilitation is incomplete, activities such as cutting, pivoting, jumping, decelerating, or landing can place a greater load directly on the ligament rather than being absorbed by the muscles around the knee joint. In some cases, people may shift weight or alter their movements to protect the previously injured side, which adds extra stress to the knee and leads to a complete ACL tear.

Muscle Imbalances and Reduced Lower-Body Strength

Balanced muscular support plays an important role in protecting the knee function. An imbalance between strong quadriceps and weaker hamstrings can reduce the knee’s ability to control the forward movement of the shin bone during intense physical activity.

Similarly, weak hip muscles and reduced core strength can alter lower-limb alignment and increase mechanical stress on the injured ACL. Over time, these imbalances may reduce shock absorption and increase the risk of ACL rupture.

Impaired Neuromuscular Control and Fatigue

Neuromuscular control refers to the body’s ability to coordinate muscle activation and maintain joint positioning during movement. When this muscular system is compromised, your muscles may respond slowly to sudden changes in direction, speed, or landing forces. If you’re physically fatigued, it can further impair neuromuscular control, leading to reduced reaction time, poorer balance, and decreased muscular coordination. As your movement quality declines, the knee loses stability, placing greater stress on the ACL and increasing the risk of injury.

Pre-Existing Joint Degeneration

If you have knee arthritis or other forms of joint degeneration, it may increase the risk of anterior cruciate ligament (ACL) injury. In arthritic knees, the protective cartilage gradually degrades, leading to uneven joint surfaces. This surface disrupts normal movement patterns and alters load distribution within the knee joint.

As a result, the anterior cruciate ligament may be subjected to increased stress during everyday activities and during athletic movements involving pivoting and sudden changes in direction. In addition, inflammation, joint stiffness, and reduced range of motion can further impair muscle activation. Over time, these combined factors can weaken knee function and increase the risk of ACL sprains or tears.

What Should You Do Immediately After a Possible ACL Injury?

After an ACL injury, you should discontinue physical activity, rest the knee, and apply ice for 15–20 minutes several times a day. You should also use compression with an elastic bandage and elevate your leg above your heart to control swelling and reduce further ligament strain. However, to prevent further ligament damage, consult our sports medicine specialists, Dr. Charles Ruotolo.

He evaluates your knee injuries using clinical tests along with imaging, such as MRI scans, to ensure an accurate diagnosis. Based on severity, Dr. Charles Ruotolo develops an appropriate treatment plan that may include exercises, bracing, or minimally invasive reconstruction. This approach will help you restore knee strength, stability, and mobility while reducing the risk of re-injury and long-term complications. If you are experiencing knee pain, instability, or symptoms of an ACL injury, schedule your consultation today.

Which Activities Most Commonly Cause ACL Injuries?

ACL injuries commonly occur during activities that involve sudden stopping, rapid changes in direction, pivoting, awkward landings, or direct impact to the knee. These high-risk movements are common in sports such as soccer, basketball, football, skiing, and volleyball, because your knee may experience intense rotational and forward forces.

Besides that, a SpringerLink systematic review of over 5,000 ACL injury cases found that four movement categories are primarily responsible for ACL injuries. These movements include change of direction, landing, direct contact, and gear-related mechanisms. Here’s how these activities cause ACL tears or associated injuries:

Sudden Stopping and Deceleration

During sudden deceleration, the ACL experiences excessive stress as the body continues to move forward while the foot remains fixed on the ground. This creates a strong shear force within the knee joint as the quadriceps contract to stop movement. According to the NIH review, large quadriceps forces, combined with a planted foot and a low knee flexion angle, significantly increase ACL loading during deceleration tasks. If the surrounding muscles are unable to absorb this load efficiently, the ligament gets overstrained. As a result, it increases the chance of a complete or partial tear.

Rapid Direction Changes and Pivoting

Cutting or pivoting movements generate high rotational forces between the femur and tibia. When an overhead athlete changes direction quickly while the foot is fixed, the knee is forced to rotate beyond its normal range of stability. This twisting mechanism is one of the most common non-contact causes of anterior cruciate ligament rupture.

Jumping and Awkward Landings

When you land with a straight knee, inward knee collapse (valgus alignment) can lead to uneven weight distribution. These forces are not properly absorbed by the muscles, which puts pressure on the ACL and other key ligaments, such as the Posterior Cruciate Ligament (PCL). As a result, it may lead to overstretching or sudden rupture, particularly during high-intensity sports or repeated jumping.

Direct Impact on the Knee

Contact-related ACL injuries typically occur during collisions, tackles, or falls that force the knee into an abnormal alignment. A direct blow to the outer or front aspect of the knee can push it inward or backward beyond its physiological limits. This sudden displacement causes traumatic stress on the knee, which may tear your ACL.

How Is an ACL Tear Different From a PCL Tear?

An ACL tear affects the ligament in the front of the knee that stabilizes forward movement and rotation. In contrast, a PCL tear involves the ligament at the back of the knee that controls backward movement of the shinbone. ACL injuries usually occur during sudden stops, whereas PCL injuries result from direct impact or trauma.

In addition, ACL and PCL injuries differ in symptoms and recovery patterns. For instance, a completely torn ACL often causes a “popping” sound, immediate swelling, and instability during cutting or twisting motions. In contrast, PCL tears may cause milder knee swelling when walking downhill or descending stairs. Depending on the severity of your tear, treatment approaches also vary. In some cases, ACL tears may even require surgical reconstruction. On the other hand, many PCL injuries can be managed conservatively with a proper recovery plan and bracing.

Which Tests Are Used to Diagnose an ACL Tear? 

To diagnose an ACL tear, Dr. Charles Ruotolo carefully evaluates your injury history and performs a detailed physical examination. He also uses the Lachman test to detect ACL instability or minor sprains. After that, he may order Magnetic Resonance Imaging (MRI) to differentiate between an ACL vs meniscus tear or other cartilage injuries.

Here are some other tests he may perform before recommending ACL surgery to assess knee stability and joint flexibility:

• Pivot Shift Test: The doctor applies a controlled twisting and inward force while bending your knee. This will help detect sudden movement, which may indicate ACL instability.
• Anterior Drawer Test: With the knee bent at 90 degrees, the doctor attempts to pull the tibia forward. If there is greater movement on the injured leg than on the uninjured leg, it indicates a torn ACL.
• Lever Test: During this clinical test, the doctor places a fist under your calf and presses down on your thigh. It helps to determine a torn ligament.

In addition to these tests, Dr. Charles Ruotolo uses X-rays to detect fractures in the thigh bone. In cases of severe ACL injury, he may use devices such as a KT-1000 arthrometer to measure forward movement or knee instability.

What Treatments Does Dr. Charles Ruotolo Offer for a Torn ACL?

Our knee specialist, Dr. Charles Ruotolo, offers advanced targeted exercises, customized bracing, and minimally invasive ACL reconstruction techniques to restore knee stability and help patients safely return to daily activities. His personalized treatment approach is based on the severity of the injury, knee stability, activity level, and long-term recovery goals.

Before starting treatment, he performs a detailed evaluation that includes a physical examination and stability testing to determine the extent of the severe tear. For mild injuries or patients with lower physical demands, he offers conservative treatment focusing on reducing inflammation and restoring range of motion.

However, when the ACL is completely torn or the knee remains unstable during movement, Dr. Charles Ruotolo combines traditional ACL reconstruction with a LET procedure. During this technique, he uses a portion of the iliotibial band to stabilize the outside of the knee joint, significantly reducing the risk of further injury. Reach out today to rebuild knee strength and improve neuromuscular control.

When Is It Safe to Return to Sports After an ACL Injury?

You can resume sports after an ACL injury when your knee has regained full strength, stability, and functional performance without pain or swelling. Depending on injury severity and treatment, recovery may take at least 9 months, or even 12 months. However, before you resume athletic activity, Dr. Charles Ruotolo evaluates the following factors to ensure your knees are stable:

Knee Strength and Muscle Recovery

Our orthopedic surgeon, Dr. Charles Ruotolo, evaluates whether you have regained near-equal strength in your injured knee. For this purpose, he may analyze the strength of the quadriceps, hamstrings, and hip muscles, which support and stabilize your knee. If these muscles are weak, your knee is exposed to increased stress during sudden direction changes, increasing the risk of serious injury.

Restored Stability and Movement Control

Our surgeon may analyze whether your knee feels stable and controlled during dynamic movements. Proper neuromuscular control ensures your muscles respond quickly and efficiently to protect your joint. If your knee still feels unstable or causes significant pain during movement, it indicates that your recovery is incomplete.

Successful Functional Testing

Before you return to sports, our knee surgeon, Dr. Charles Ruotolo, performs functional tests that mimic real athletic activities. It may include hopping drills, balance exercises, agility tasks, and sport-specific movements. These tests help assess whether both legs perform equally and your knee can withstand high-impact stress.

Absence of Pain, Swelling, or Instability

He also evaluates whether you can move and perform daily activities without pain, swelling, or stiffness in your knee. If any of these symptoms persist, it usually indicates that your knee has not fully healed. In such cases, you may need additional rehabilitation.

How Can You Reduce the Risk of an ACL Tear?

You should strengthen your leg muscles, improve your balance, and use proper sports techniques to reduce the risk of an ACL tear. You should also perform a warm-up session before activity, avoid sudden direction changes without control, and wear appropriate footwear.

Additionally, to reduce the risk of future ACL injury, focus on neuromuscular training programs that enhance coordination between the brain and muscles. In fact, the PMC study shows that neuromuscular training focused on plyometrics and strengthening exercises is highly effective at preventing ACL injury.

Similarly, you can perform exercises like squats, lunges, plyometrics, and agility drills to help stabilize the knee joint. Moreover, you can practice jumping and landing softly on the balls of your feet, rolling back onto your heels. Besides this, practice single-leg balances, single-leg squats, and Bosu ball exercises. You can also train your core with planks and side planks to rebuild full-body control.

Visit Total Orthopedics & Sports Medicine for ACL Tear Diagnosis & Treatment in East Meadow!

After an ACL tear, you may struggle to perform simple activities such as walking, climbing stairs, turning quickly, or standing for long periods due to knee instability. In severe cases, the injury can also affect your ability to participate in sports, maintain an active lifestyle, or perform physically demanding tasks.

At Total Orthopedics and Sports Medicine, Dr. Charles Ruotolo, our trusted orthopedic specialist, combines advanced diagnostic tools and surgical techniques to accurately identify and treat ACL injuries. Additionally, we provide online patient convenience tools and clear surgical instructions to ensure a smooth recovery. Visit us at 2339 Hempstead Turnpike, East Meadow, NY 11554, or call 855-321-6784 to get an expert diagnosis of your ACL tear.

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