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4 Common Causes of ACL Tears

6th Jun 2023 | 0 comments

Anterior Cruciate Ligament (ACL) tear is a common knee injury that is often debilitating and can significantly impact a person’s quality of life. Both men and women can experience ACL tears, and they can occur in various situations. 

Understanding the causes of ACL tears can help you take preventive measures and reduce your risk of injury. In this article, we’ll explore four common causes of ACL tears and their associated risk factors, before exploring  surgical options available in Singapore.

What is ACL?

The ACL is a strong band of connective tissue in the knee that connects the thigh bone (femur) to the shin bone (tibia). It runs diagonally across the middle of the knee, working with other ligaments and structures to ensure proper joint movement and prevent excessive motion.

The primary function of the ACL is to control the forward movement of the tibia to the femur and limit rotational movements of the knee joint.

4 Common Causes of ACL Tears

Sudden Stops or Changes in Direction

One of the primary causes of ACL tears is sudden deceleration or change in direction during physical activities. Sudden movements frequently happen in sports involving pivoting, cutting, and rapid changes in motion. 

Basketball, football, rugby and tennis are some examples of sports where these movements are common. When the foot is firmly planted and the body suddenly shifts direction, the ACL can experience excessive stress, leading to tears.


Hyperextension of the knee happens when the knee joint is forced out of its natural range of motion, stretching or tearing the ACL. Hyperextension can happen during various activities, such as landing from a jump with improper technique, especially if the landing is on a straightened or locked-out knee. 

In jumping and landing activities, gymnasts, dancers, and athletes are particularly susceptible to hyperextension-related ACL tears.

 Direct Impact

A direct impact on the knee, such as knocking into a hard surface or a collision between players, can result in an ACL tear. It can occur in contact sports like football, rugby, and ice hockey. 

The impact force can cause the knee joint to buckle or twist unnaturally, damaging the ligament. Wearing appropriate protective gear and adhering to proper playing techniques can help reduce the risk of ACL tears caused by direct impact.

Landing Incorrectly

Improper landing technique after a jump is another common cause of ACL tears. When landing from a jump, especially from a significant height, it’s crucial to maintain proper knee alignment and absorb the impact using the hips and core muscles. Allowing the knees to collapse inward upon landing can strain the ACL and other supporting structures. 

Athletes, particularly those involved in sports like volleyball and parkour, should focus on learning and practising correct landing techniques to lower their risk of injury.

Factors That Increase the Risk of ACL Tears


Women are at a higher risk of ACL tears compared to men. In a study, the ACL injury occurrence of women to men is 3.5 times higher in basketball and 2.8 times higher in soccer. This difference is attributed to hormonal variations, anatomical differences, and biomechanics.

Muscle Imbalance

The risk of ACL tears is higher when there is an imbalance or weakness of the muscles around the knee, reducing support and stability.

Previous Injury

A history of ACL tears or other knee injuries can weaken the ligaments and structures around the knee, making it more prone to future injuries.

Poor Technique

Incorrect body mechanics and movement patterns during sports or physical activities can put undue stress on the ACL and increase the risk of tears.

Lack of Conditioning

Inadequate conditioning and insufficient warm-up can contribute to muscle fatigue, reducing the ability of the muscles to support the knee joint effectively.

When to See a Doctor

You must seek medical attention promptly if you experience symptoms like:

  • a popping sound at the time of injury
  • immediate swelling
  • severe pain 
  • instability in the knee 

Ignoring these symptoms or attempting to push through the pain can exacerbate the ACL injury and lead to further complications.

Treatment Options for ACL Tear

The treatment approach for an ACL tear depends on several factors, including the severity of the tear, the individual’s activity level, overall health, and personal preferences. Here are the primary treatment options available for ACL tears.

1. Conservative Treatment

Conservative treatment is often considered for individuals with partial ACL tears or those not highly active. This approach aims to manage symptoms, improve knee stability, and restore function without surgical intervention. Conservative treatment options include.

  • Physical therapy
  • Bracing
  • Activity modification

2. ACL Reconstruction Surgery

ACL reconstruction surgery might be recommended for more severe ACL tears, especially those that result in knee instability and impact an individual’s desired activity level. 

Unlike a total knee replacement procedure, where artificial implants are used, this surgery replaces the torn ligament with a graft from another part of the body or a donor. It allows the knee to regain stability and strength.

3. Rehabilitation

Rehabilitation exercises are often recommended for individuals after undergoing ACL surgery and may be included in other treatment methods. This is because rehabilitation exercises are critical to ACL tear management. It aims to restore strength, flexibility, and range of motion to the knee and improve overall functional abilities.

ACL Treatment and Reconstruction Surgery in Singapore

You should consult a reputable doctor in Singapore to diagnose and treat your condition. If ACL reconstruction surgery becomes necessary, a doctor who can take care of your long-term rehabilitation is crucial. 

Spire Orthopaedic Centre specialises in sports injuries, arthritis, trauma, joint replacements, and soft tissue repair. Our skilled team of surgeons, experts, and therapists is dedicated to understanding your needs.

Contact us for a physical assessment.